Dissertations / Theses on the topic 'Energy expenditure'

This thesis aims to determine energy compensation following exercise induced energy expenditure (ExEE). The specific objectives were: I) to determine the impact of the time spent performing physical activity (PA) of varying intensities on body weight and composition (Study 1); II) to determine the overall energy compensation and the major predictors of energy compensation through the systematic review approach (Study 2); III) to develop new methods to measure energy intake (EI) (Study 3) and time spent performing different activities (Study 4); IV) to determine the effects of a lower (LI) and higher intensity (HI) ExEE intervention on energy compensation (Study 5); and V) to investigate the inter-individual variability regarding exercise induced energy compensation (Study 6). In Study 1, women spending more time performing light-intensity PA were shown to have lower adiposity compared to women spending more time performing moderate- and high-intensity PA. Results from Study 2 (systematic review) show an overall energy compensation of 25% following exercise interventions and that fat mass (FM), exercise intensity and duration of the intervention are the main predictors of energy compensation. To better capture energy compensation (i.e., EI and EE), new methods to measure EI and time spent performing activities were developed (Studies 3 and 4) and used in the following studies. In Study 5, overweight/obese women training at HI displayed higher energy compensation when compared to women training at LI, which was accompanied by a reduction of NSPA (non-structured physical activity) and a greater amount of time spent lying down. Results from Study 6 showed that complete compensators (CC) had higher EI, fat and carbohydrate intake at the onset of the ExEE intervention when compared to incomplete compensators (IC). However, the results also showed that dietary disinhibition was increased, whereas NSPA was decreased at the end of the intervention in IC. Taken together, these studies emphasize that weight loss following exercise is impeded by energy compensation. In addition to the impact of FM, exercise intensity and duration of the intervention on energy compensation, NSPA and cognitive factors also seem to modify energy compensation that occurs as a result of exercise.

This thesis is concerned primarily with the measurement of total energy expenditure in infancy. Until the advent and subsequent development of the doubly labelled water technique for the assessment of carbon dioxide production rate in "free-living" individuals measurements of total energy expenditure in infants and children were virtually impossible. Thus measurements of total energy expenditure using this relatively new technique are of burgeoning interest to nutritionists, clinicians and human biologists.

The increased participation in elite wheelchair sport has provided the need to investigate the physiological requirements of wheelchair sporting competition and daily wheelchair propulsion. However, from a nutritional perspective, guidelines that have been established from the able-bodied population tend to be used by the practitioners working in disability sport and it is not known whether this information is directly transferable to the wheelchair athlete. Wheelchair sport is complex and athletes differ with respect to their sports classification based on factors relating to disability and functional capacity. Therefore, if nutritional guidance is required to optimise performance then information regarding energy expenditure (EE) in the wheelchair sports population becomes important for specific feedback. The aim of this thesis was to investigate EE in wheelchair athletes. The results from Chapter 3 found resting energy expenditure (REE) in tetraplegic athletes to be lower than that calculated using predictive equations derived from an ablebodied cohort. However, paraplegic athletes showed comparable values to those which were predicted, suggesting these equations may be of use in paraplegic athletes. Chapter 4 extended this work and found similarities in the REE of the two aforementioned cohorts. This could have been due to the similarities that were found in their total-body fat free mass (FFM). The results from Chapter 5 showed EE reduced after both a short 36 minute exposure of wheelchair propulsion and after 3 weeks of wheelchair propulsion practice in novice wheelchair users. Temporal parameters improved after the practice period, suggesting there is an association between EE and propulsion technique. Chapter 6 extended these findings with results confirming that experienced wheelchair users expended significantly less energy during wheelchair propulsion than novice individuals who had up to 3 weeks practice. It is clear that EE of daily wheelchair ambulation should not be a generic value and different levels of experience must be considered so that the nutritional needs can be tailored accordingly. Chapters 7 and 8 examined the physiological demands of elite competitive wheelchair basketball players in relation to the International Wheelchair Basketball Federation (IWBF) classification categories and identified differences in the physiological demands and physiological fitness of wheelchair basketball and tennis players. These results found that IWBF Class 3 - 4.5 (high point) players expended more energy per hour during competition than those with a lower classification (IWBF Class 1 - 2.5). However, when actual playing time was considered the low classification group showed a similar EE to the higher classification group. Furthermore, wheelchair basketball players had a higher EE per hour than wheelchair tennis players during elite competition. However, the wheelchair tennis players spent a significantly longer duration on court resulting in similar EE during a typical competition within each sport. This suggests nutritional advice should be tailored both to the duration of competitive play (where EE may be similar between sports (basketball vs. tennis)); and to training (where athletes with a higher functional capacity may have higher EE). This thesis revealed several important physiological considerations to appreciate when investigating the EE of wheelchair sportsmen and women. Findings would suggest that type of disability, wheelchair propulsion experience and sport classification are all important considerations for the accurate assessment of EE in this cohort of athletes.

Adolescence is a life history transition of individual and evolutionary importance: the body begins to allocate energy available above maintenance costs away from somatic growth and towards reproductive function. This study investigates how both distal, intergenerational effects and proximal, seasonal changes in energy availability impact the way adolescent female bodies allocate energy among linear growth, fat and lean mass, activity, and metabolic function. The research follows up on a prenatal supplementation study conducted by the British Medical Research Council in rural Gambia between 1989 and 1994. Pregnant women were randomized to receive daily supplements of 1015 kcal either from week 20 of pregnancy until delivery or during the first 20 weeks of lactation. The 67 adolescent daughters included in the follow up study were born to women in both groups during the rainy agricultural season, the period of the year associated with weight loss, poor perinatal outcomes, and high impact of the pregnancy supplement on birth weight. Anthropometry, body composition, daily saliva, weekly serum, and weekly fasting urine samples for C-peptide of insulin were collected during one month each in the 2009 rainy agricultural season, the 2010 dry harvest season, and the 2010 rainy agricultural season. Participant heart rates were calibrated to oxygen consumption each season, and 24-hr accelerometer and heart rate data were recorded to estimate free-living energy expenditure. It was found that pregnancy supplementation status did not predict infant or adolescent phenotype in the study sample. Maternal postpartum weight, however, was a powerful positive distal predictor of adolescent size. The daughters of heavier mothers produced less leptin per unit fat mass. Under conditions of high energy expenditure and low intake, adolescent women who were growing in height mobilized adipose stores and acquired lean mass, while developmentally older women maintained fat stores at the expense of lean mass. Married adolescents in the sample were older, had lower fasting C-peptide of insulin, had higher absolute energy expenditure, and spent more of their total energy budgets in activity than did unmarried peers.
Human Evolutionary Biology

The purpose of this investigation is to examine the energy demand of heavy metal drummers during rehearsal in order to understand the physiological responses. This information may lead to a better understanding of energy expenditure and add to the compendium of physical activity. The investigation consisted of eight apparently healthy 20 to 37-year-old males were recruited for this investigation. Information gathered during the drum test was average VO2, VO2peak, HR in beats per minute (bpm), metabolic equivalents (METs), and energy expenditure (EE) expressed in calories (kcals) per minute and per hour. Rating of perceived exertion (RPE) was used in addition to VO2 and HR values to assess physical demand. The Bruce Protocol maximal treadmill test was administered to compare the participants VO2max to their VO2peak while drumming. The EE during the 40-minute drum test was 387.05 + 83 kcals with an estimated hourly EE of 567.33 + 111.7 kcals. VO2, VO2peak, VE, and HR was 21.4 + 4.1 ml/kg/min, 33.9 + 8.1 ml/kg/min, 63.5 + 19 L/min, and 150.4 + 13.6 bpm respectively. The average MET level reached was six. RPE was 13.8 + 1.2 and is expressed as “somewhat hard” in difficulty according to the ACSM. Those categorized as having an average level of fitness reached 50-59% of their VO2max while the two individuals categorized as having an excellent level of fitness reached 42-45% of their VO2max. In conclusion, heavy metal drumming is a form of physical activity that is of moderate intensity and can be compared to other forms of recreational and work related physical activity.

I investigated the effects of continuous administration of fluoxetine, a serotonin reuptake inhibitor, on energy expenditure, body temperature, and thyroid and catecholamine metabolism during weight reduction using a very low calorie diet (VLCD, Optifast, 1757 kJ/day) followed by a balanced deficit diet (BDD, 5016 kJ/day). Fluoxetine (60 mg/day by mouth, n = 10) or placebo (n = 10) were administered during 3 weeks of inpatient VLCD followed by 8 weeks of outpatient BDD in a double-blind, randomized design. A similar amount of weight was lost in both groups during the VLCD, but by the end of the BDD total weight loss in the fluoxetine group was significantly greater (11.0 $ pm$ 1.1 kg vs. 7.0 $ pm$ 1.0 kg, mean $ pm$ SEM, p $<$ 0.015). Resting metabolic rate (RMR) increased by 4.4 $ pm$ 1.8% (p $<$ 0.01) in the fluoxetine group but did not change in the placebo group during the first week of the VLCD, but subsequently decreased significantly in both groups as dieting continued. However, RMR remained consistently higher in the fluoxetine group for the duration of the VLCD period. No further change in RMR occurred in either group during the BDD period. The thermic effect of food did not change after VLC dieting plus fluoxetine or placebo treatment. Body temperature increased within 2 days of fluoxetine treatment by a mean of 0.3$ sp circ$C, p $<$ 0.025 and remained elevated throughout the VLCD but was unchanged in the placebo group. VLCD therapy reduced serum levels of T$ sb3$, free T$ sb3$ Index and 24-hour urinary excretion of dopamine, norepinephrine, metanephrine and normetanephrine equivalently in both groups. A thermogenic effect of fluoxetine is demonstrated in humans for the first time. The anorectic effect of fluoxetine may be related to its temperature elevating effect.

The purpose of this study was to assess the performance, ratings of perceived exertion, metabolic responses, and energy expenditure as individuals participated in interactive video game play. There were 14 participants that participated in the study, whose age was 20.1 ± 1.64 years of age. Participants completed a maximal aerobic test to exhaustion (VO2max test), and then 30 minute testing session on both the Kinect Adventures (K) and Wii Fit Plus game. Data were analyzed using a dependent t-test and one-way ANOVA. Significance was accepted at P ≤ 0.05. Energy expenditure and RPE were significant in both exergames interactive game play P=0.044 and P < 0.05, respectively. In addition, heart rate (P=0.001) and performance during exergame play P=0.00015 were of significance in the Xbox Kinect and Wii Fit Plus. In conclusion, we found that individuals participating on the exergame Xbox Kinect expends more calories and work at a higher intensity than the Wii Fit Plus, thus justifying an alternative way to participate in physical activity via exergames. As an alternative way to exercise, individuals can meet the daily requirements of energy expenditure of moderate intensity, which is 150-400 kcals.

Renal replacement therapy, in the form of dialysis or transplantation, is the cornerstone of management for end-stage renal disease. UK renal registry shows nearly half of those needing renal replacement therapy are treated by dialysis – predominantly by haemodialysis. Patients on renal replacement therapy have increased mortality risk compared to age matched general population. Moreover, some specific subgroups of patients on haemodialysis have increased risk of mortality than expected. The survival benefit seen in women in the general population is attenuated resulting in similar survival for men and women on haemodialysis therapy. In addition, obese individuals and those of non-Caucasian origin have better survival outcome. Though the underlying reason for these findings is not clear and is likely to be multi-factorial, it has been hypothesised that this paradox could be due to the current practice of normalising dialysis dose to total body water. A number of metabolic factors – body surface area, resting energy expenditure and total energy expenditure – have been proposed as alternative to total body water for scaling dialysis dose. There were two overarching aims of this work – one was to study the effect of declining renal function on resting and total energy expenditure and to study the influence of various energy expenditure measures on uraemic toxin generation. The second was to study the impact on survival outcome of using these alternate parameters for normalising dialysis dose and to derive dialysis dose adjustments based on these metabolic parameters. In order to study these aims, studies were designed to explore different aspects of energy expenditure measures along with a longitudinal study to examine the impact of these parameters on survival outcome. The relationship between energy metabolism, body composition and uraemic toxin generation was studied with a retrospective analysis of 166 haemodialysis patients in whom urea generation rate was used as surrogate marker of uraemic toxin generation. It was found that total energy expenditure and fat-free mass predicted uraemic toxin generation after adjustment for other relevant variables. This study provided the preliminary data which was useful in designing further studies for this work. The effect of renal function on resting and total energy expenditure was studied in 80 patients with varying stages of chronic kidney disease who were not on renal replacement therapy. Resting and total energy expenditures were measured directly using gold-standard methods. It was found that declining renal function did not have a significant influence on either of these measures. This supports the hypothesis that metabolic rate is the driving force for glomerular filtration rate and not vice-versa. The directly measured energy expenditure measures were also found to have a moderately strong relationship with urea generation rate in these patients not on renal replacement therapy. The impact of physical activity on uraemic toxin generation, and thereby dialysis requirement, was studied in a prospective cross-sectional study of 120 haemodialysis patients in whom the physical activity was measured by an accelerometer device. Results from the study showed physical activity level to be a significant predictor of uraemic toxin generation after adjustment for gender and body size differences. This study results stressed the importance of adjusting dialysis dose based on individual’s physical activity level. To study the impact of using metabolic factors as normalising parameter for scaling dialysis dose on survival outcome, a large-scale longitudinal study was conducted with 1500 maintenance haemodialysis patients recruited for the study. Dialysis dose-related parameters and survival outcomes were collected at baseline and at various time points during the follow-up period of 18 months. Study results were analysed in two parts - the theoretical basis for using these metabolic factors as scaling parameters was explored which showed that current minimum target dialysis dose risks under-dialysis in certain subgroups of patients and using these alternative parameters may provide a more equivalent dialysis dose across individuals of different body sizes and gender. With these results arguing for potential use of the alternative parameters, the impact on survival of using them were examined. It was found that all three parameters performed better than the current parameter (total body water) with regards to predicting mortality. Total energy expenditure was found to be the best parameter with the lowest hazard ratio for risk of death. The study data was also analysed to derive an algorithm for adjustment of minimum target dialysis dose based on body size and physical activity level. This newly derived minimum dose target was also shown to impact on survival with those underdialysed based on this criteria having poorer survival outcomes. To understand the impact of whole body protein turnover on resting energy expenditure and uraemic toxin generation, a cross-sectional study was conducted on 12 patients with advanced CKD – 6 each in pre-dialysis CKD and haemodialysis group. It was found that haemodialysis patients had higher rate of protein turnover compared to pre-dialysis patients. Whole body protein turnover was found to contribute significantly to resting energy expenditure and had a moderately strong relationship with urea generation rate. In the course of these studies, two questionnaire tools have been validated for use for clinical and research purposes – one is a self-report comorbidity questionnaire and the other, the Recent Physical Activity Questionnaire. The comorbidity questionnaire was developed as part of this work and was validated against Charlson Comorbidity Index. The Recent Physical Activity Questionnaire was validated for physical activity data collection and energy expenditure calculation against the gold-standard doubly labelled water method. In conclusion, it has been demonstrated that metabolic factors such as body surface area, resting energy expenditure and total energy expenditure are more closely related to uraemic toxin generation compared to total body water. It has also been demonstrated that physical activity contributes to metabolic waste production and may necessitate changes in dialysis requirement. It has been shown that these metabolic factors, when used as scaling parameter for dialysis dosing, may predict survival better than the current parameter in use. The algorithm for dialysis dose adjustment and the questionnaires validated in this work have provided novel tools for further research studies and clinical practice. The central hypothesis of this work is that some metabolic factors may be better markers of uraemic toxin generation compared to total body water. It is hypothesised that modifications in dialysis practice based on these factors may improve the quality of haemodialysis and favourably impact on survival outcome for patients with end-stage renal disease. The work presented here largely supports this hypothesis.

The accurate measurement of total energy expenditure is a cornerstone of metabolic research. However, there is a lack of measurement methods that are valid, objective, inexpensive, and easy to use. Accelerometry, along with validated prediction equations for resting energy requirements, may provide an opportunity to fill this void. Twenty weight stable adults (12 female, 8 male) who recently participated in a controlled feeding study comprised the study sample. Total energy requirements were assessed from the controlled feeding period in which weight stability was achieved using the intake-balance method. Resting energy expenditure was assessed using the Mifflin-St. Jeor equation. Participants wore accelerometers to objectively assess habitual physical activity. The accelerometer data obtained along with subjects' demographic and biometric data were used to predict non-resting energy expenditure (NREE) using step-wise linear regression in JMP. Bland-Altman plots and Spearman's Rho correlations were used to determine the validity of the total energy requirements obtained from the sum of the predicted non-resting energy expenditure. Estimated resting energy expenditure was compared with the total energy requirements assessed using the intake-balance method from the controlled feeding period. The resulting prediction equation is as follows: 480.93 – 180.69(sex) + 0.21(Accelerometer kcals) + 617.98(BF%) = AEE. The sex was coded as 1 for females and 0 for males. This prediction model has a coefficient of determination of 0.74 (0.70 adjusted). On average, the model overestimates AEE by 76 kcals. This new model could be the key to accurately, inexpensively and objectively measuring total energy requirements.
Master of Science
Accurate measurement of the total amount of energy (i.e. calories) utilized by the body throughout the day, also known as total energy expenditure, is a vital component of metabolic research. However, there is a lack of measurement methods that are valid, objective, inexpensive, and easy to use. Accelerometers combined with equations designed to predict total energy expenditure may be able to fill this gap. Accelerometers are devices worn on the body that measure accelerative forces from physical activity. Twenty weight stable adults (12 female, 8 male), who recently participated in a study in which all dietary intake and exercise were closely monitored (controlled feeding study), comprised the study sample. The amount of energy needed to maintain weight (total energy requirements) was assessed from the controlled feeding period in which weight stability was achieved. Resting energy expenditure, the energy burned while the body is at rest, was assessed using an equation often used to estimate energy expenditure, the Mifflin-St. Jeor equation. Participants wore accelerometers to objectively assess habitual physical activity. The accelerometer data obtained along with subjects’ demographic (age, sex) and biometric (height, weight, BMI, etc.) data were used to predict non-resting energy expenditure (resting energy expenditure subtracted from total energy expenditure). Multiple statistical tests were used to determine the validity of the total energy requirements obtained from the sum of the predicted non-resting energy expenditure (NREE) and resting energy expenditure. Estimated resting energy expenditure was compared with the total energy requirements assessed using the intake-balance method from the controlled feeding period. The resulting prediction equation is as follows: 480.93 – 180.69(sex) + 0.21(Accelerometer kcals) + 617.98(BF%) = NREE. The sex was coded as 1 for females and 0 for males. This prediction model has a coefficient of determination of 0.74 (0.70 adjusted), which means 70% of the variation in non-resting energy expenditure was explained by changes in the variables in the equation. On average, the model overestimates NREE by 76 Calories per day. This new model could be the key to accurately, inexpensively and objectively measuring total energy requirements.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (page 24).
With the current rate at which technology is advancing, MIT has to update and replace out-of-date facilities as well as add new ones to stay at the forefront of university research. As MIT continues to expand its facilities, the amount of energy required to run those facilities will also increase. An analysis of future energy usage allows for energy saving systems to be planned before the facilities are complete, and implementation can be started before the energy has been spent. This thesis will be such an analysis on the energy usage of MIT's current capital projects, as well as the historical trends of MIT's energy usage. Conclusions will be drawn on how much these facilities or renovations will increase the university's energy expenditure by comparing facilities that currently exist to ones that are still in planning. By comparing the EUI of planned capital projects to that of existing facilities, a range was found for each facility's energy usage. Using this data, it was found that MIT will see a change in purchased energy between -16.5% and 4.28% by 2030. The low energy estimate matches with MIT's claimed -15% by 2030. The high energy estimate does not match, and shows that the rate at which MIT is currently expanding is not sustainable until 2030.
by Michael Hartman.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering

An exercise-induced energy deficit may affect post-exercise energy intake, physical activity energy expenditure (PAEE) and energy balance hormones. Therefore, the objective of this thesis was to investigate the impact of a single bout of exercise either of moderate (40% O2max) or high (70% O2max) intensity on post-exercise energy intake, physical activity energy expenditure and energy balance hormones in both sedentary and active males. Physical activity energy expenditure increased between 38 and 62 hours following moderate intensity exercise in sedentary males (Chapters 3 and 4). This was due to increased light intensity energy expenditure (2.4-4.79 METs) such as standing and walking activities (Chapter 4). The Change in PAEE was not associated with circulating leptin and adiponectin concentrations. There was no impact of a single bout of exercise on post-exercise energy intake in sedentary males during a buffet meal (Chapter 4). Chapter 5 aimed to determine whether changes in PAEE, energy intake, and energy balance hormones were related to physical activity status. Interestingly, plasma acylated ghrelin concentration was suppressed while total peptide YY (PYY) concentration tended to be elevated after high intensity exercise in active males (Chapter 5). However, there was no impact of either moderate or high intensity exercise on PAEE and post-exercise energy intake in active males. The final study (Chapter 6) determined whether high intensity exercise in the fed state after a few days of food restriction had an impact on circulating energy balance hormones. Circulating postprandial total PYY and pancreatic polypeptide (PP) were increased for one hour after high intensity exercise in active men. There was no change in PAEE and post-exercise energy intake after exercise.

Humans can only survive the low barometric pressure of altitudes above 6000m by making a complex series of adaptations. The energetics of human survival at such extreme altitudes have not been widely studied. Objectives were to compare the doubly labelled water (DLW) and intake-balance (IB) methods to estimate daily energy expenditure while climbing between 6000 and 8046m and to investigate the putative metabolic cost involved with the process of acclimatization to extreme altitude. Reliability of the DLW method to provide an accurate and portable means to measure human energy expenditure depends upon a series of assumptions regarding the flux of tracer and tracee across the physiological compartments of measurement. Additional objectives were to review and examine the proficiency of these assumptions to account for perturbations experienced while using DLW while climbing at extreme altitude. Findings suggest that the use of DLW at extreme altitudes requires special consideration towards elevated rates of fractional isotope loss, inter-subject isotope transfer, alterations in total body water, changes in background isotopic abundance, and choice of sampling technique. Revised strategies directed at achieving these aims are calculated. Results from extreme altitude indicate that IB and DLW techniques each provide similar estimates of group mean energy expenditure despite substantial changes in body weight and composition and that the metabolic cost for the process of acclimatization accounts for roughly 12% of total daily energy expenditure. Problems associated with maintaining energy balance while climbing at extreme altitude are related to low energy intakes, approximately only 70% of energy demands, and energy expenditure values that are comparable to those of highly trained endurance athletes at sea-level.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第20433号
農博第2218号
新制||農||1048(附属図書館)
学位論文||H29||N5054(農学部図書室)
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 廣岡 博之, 教授 久米 新一, 教授 今井 裕
学位規則第4条第1項該当

Revised; Originally published: 10/2008
3 pp.
Recently, a number of global positioning system (GPS) devices have been introduced commercially which exploit GPS, transforming frequent measurements of time and location, into an estimate of energy expenditure. This fact sheet reviews how GPS watches (GPS fitness units) measure energy expenditure of individual during physical activity. We list popular GPS watches that are on the market and show pros and cons of these watches. After our field testing, we decided that the Garmin Forerunner 305 is our best pick for the GPS watch. We included information on geocaching, which is one of several popular outdoor activities using a GPS receiver or other navigational techniques.

4 pp.
Recently, a number of global positioning system (GPS) devices have been introduced commercially which exploit GPS, transforming frequent measurements of time and location, into an estimate of energy expenditure. This fact sheet reviews how GPS watches (GPS fitness units) measure energy expenditure of individual during physical activity. We list popular GPS watches that are on the market and showed pros and cons of these watches. After our field testing, we decided that Garmin Forenunner 305 is our best pick for the GPS watch. We included information on Geocashing, which is one of popular outdoor activities using GPS receiver or other navigational techniques.

There is an increase in the prevalence of obesity among people with schizophrenia thought to be due in part to the weight enhancing side-effects of medications commonly used to treat the symptoms of schizophrenia. Despite the deleterious health effects associated with obesity and its impact on quality of life and medication compliance, little is known about body composition and energy expenditure in this clinical group. The primary purpose of this thesis was to enhance understanding of body composition and energy expenditure, particularly resting energy expenditure in men with schizophrenia who take atypical antipsychotic medications. Unique to this investigation is the evaluation of clinical tools used to predict body composition and energy expenditure against reference methodologies in men with schizophrenia. Further, given the known links between obesity and physical activity, an additional but less comprehensive component of the thesis was a consideration of total and activity energy expenditure in addition to the interaction between psychiatric symptoms, side-effects of antipsychotic medications and physical activity also occurred as part of this thesis. Collectively, the goals of this thesis were addressed through a series of studies – the first two studies were related to the measurement and characteristics of body composition in men with schizophrenia, while the third and fourth studies were related to the measurement and characteristics of resting energy expenditure in men with schizophrenia. The fifth and sixth studies the utilised doubly labelled water technique to quantify activity and total energy expenditure in a small group of men with schizophrenia and explored the use of accelerometry in this cohort. The final study briefly considered the impact of psychiatric symptoms and self-reported medication side-effects on objectively measured physical activity. In the first study, thirty-one male adults previously diagnosed with schizophrenia and sixteen healthy male controls were recruited. Estimates of body composition derived from an anthropometry-based equation and from bioelectric impedance analysis (BIA) using deuterium dilution as the reference methodology to determine total body water were compared. The study also determined the validity of equations commonly used to predict body composition from BIA in the men with schizophrenia. A further aim was to determine the superiority of either BIA or body mass index (BMI) as an indicator of obesity in this cohort. The inclusion of the control group, closely matched for age, body size and body composition demonstrated that there was no difference in the ability of body composition prediction methods to distinguish between fat and fat-free mass (FFM) in controls and men with schizophrenia when both groups had similar body composition. However this study indicated that an anthropometry-based equation previously used in people with schizophrenia was a poor predictor of body composition in this cohort, as evidenced by wide limits of agreement (25%) and systematic variation of the bias. In comparison, the best predictor of percentage body fat (%BF) in this group was gained when impedance values were used to predict percentage body fat via the equation published by Lukaski et al (1986). Although percentage body fat was underpredicted using the Lukaski et al. (1986) equation, the mean magnitude was relatively small (1.3%), with the limits of agreement approximately 13%. Linear regression analysis revealed that %BF predicted using the Lukaski et al. (1986) equation explained 25% more of the variance in percentage body fat than BMI. Further, this study also indicated that BIA was more sensitive than BMI in distinguishing between overweight and obesity in this cohort of men with schizophrenia. Because of the almost exclusive use of BMI as an indicator of obesity in people with schizophrenia, the level of excess body fat may be in excess of that previously indicated. The second study extended the examination of body composition in men with schizophrenia. In this study, the thirty-one participants with schizophrenia (age, 34.2 ± 5.7 years; BMI, 30.2 ± 5.7 kg/m2) were individually matched with sedentary controls by age, weight and BMI. Deuterium dilution was used to distinguish between FFM and fat mass. The previous study had indicated that while BIA was a suitable group measure for obesity, on an individual level the technique lacked the precision required for investigating body composition in men with schizophrenia. Waist circumference was used as an indicator of body fat distribution. The findings of this study indicated that in comparison with healthy sedentary controls of similar body size and age, men with schizophrenia had higher levels of body fat which was more centrally distributed. Percentage body fat was on average 4% higher and waist circumference, on average 5 cm greater in men with schizophrenia than the sedentary controls of the same age and BMI. Further, this study indicates that the use of BMI to predict body fat in men with schizophrenia will result in greater bias than when it is used to predict body fat in other sedentary men. Commonly used regression equations to predict energy requirements at rest are based on the relationships between weight and resting energy expenditure (REE) and in such equations, weight acts as a surrogate measure of FFM. The objectives of study three were to measure REE in a small group of men with schizophrenia who were taking the antipsychotic medication clozapine and to determine whether REE can be predicted with sufficient accuracy to substitute for the measurement of REE in the clinical and/or research settings. Body composition was determined using deuterium dilution and REE was measured using a Deltatrac Metabolic Cart via a ventilated hood. The male participants, (aged 28.0 ± 6.7 yrs, BMI 29.8 ± 6.8 kg/m2) were weight stable at the time of the study and had been taking clozapine for 20.5 ± 12.8 months, with doses of 450 ± 140 mg/day. Of the six prediction equations evaluated, the equation of Mifflin et al. (1990) with no systematic bias, the lowest bias and the lowest limits of agreement proved to be the most suitable equation to predict REE in this cohort. The overestimation of REE can be corrected for by deducting 160 kcal/day from the predicted REE value when using the Mifflin et al. (1990) equations. However, the magnitude of the error associated with the prediction of REE for an individual is 370 kcal/day. The findings of this study indicate that REE cannot be predicted with sufficient individual accuracy in men with schizophrenia, therefore it was necessary to measure rather than predict REE in subsequent studies. In the fourth study, indirect calorimetry (Deltatrac Metabolic Cart via ventilated hood) and deuterium dilution were used to accurately determine REE, respiratory quotient (RQ) and FFM in 31 men with schizophrenia and healthy sedentary controls individually matched for age and BMI. Data from this study indicated that gross REE was lower in men with schizophrenia than in healthy sedentary controls of a similar age and body size. However, there was no difference between the groups in REE when REE was adjusted for FFM using the mathematically correct method (analysis of covariance with FFM as the covariate). There was however a statistically and clinically significant difference in resting, fasted RQ between men with schizophrenia and controls, suggesting that RQ rather than REE may be an important correlate worthy of further investigation in men with schizophrenia who take antipsychotic medications. Studies five and six involved the application of the doubly labelled water (DLW) technique to accurately determine total energy expenditure (TEE) and activity energy expenditure (AEE) in a small group of men with schizophrenia who had been taking the atypical antipsychotic medication clozapine. The participants were those who took part in study three. The purpose of these studies was to assess the validity of a commercially available tri-axial accelerometer (RT3) for predicting free-living AEE and to investigate TEE and AEE in men with schizophrenia. There was poor agreement between AEE measured using DLW and AEE predicted using the RT3. However, using the RT3 to measure inactivity explained over two-thirds of the variance in AEE. This study found that the relationship between current AEE per kilogram of body weight and change from baseline weight in men taking clozapine was strong although not significant. The sedentary nature of the group of participants in this study was reflected in physical activity levels, (PAL, 1.39 ± 0.27), AEE (435 ±352 kcal/day) and TEE (2511 ± 606 kcal/day) that fell well short of values recommended by WHO (2000) for optimal health and to prevent weight gain. Given the increasing recognition of the importance of sedentary behaviour to weight gain in the general community, further examination of the unique contributing factors such as medication side effects and symptoms of mental illness to activity levels in this clinical group is warranted. The final study used accelerometry (RT3) to objectively measure activity in a group of 31 men with schizophrenia who had been taking atypical antipsychotic medications for more than four months. The purpose of this study was to explore the relationships between psychiatric symptomatology, side-effects of medication and physical activity. Accelerometry output was analysed to provide a measure of inactivity and moderate intensity activity (MIA). The well-validated and reliable standardised clinical interview, the Positive and Negative Syndrome Scale (PANSS) was used as a measure of psychiatric symptoms. Perceived side-effects of medication were assessed using the Liverpool University Neuroleptic Rating Side-Effects Scale (LUNSER). Surprisingly, there was no relationship reported between any measures of negative symptoms and physical inactivity. However, self-reported measures of medication side-effects relating to fatigue, sleepiness during the day and extrapyramidal symptoms explained 40% of the variance in inactivity. This study found significant relationships between some negative symptoms and moderate intensity activity. Despite the expectation that as symptoms of mental illness reduce, inactivity may diminish and moderate intensity activity will increase, it may not be surprising that in practice this is an overly simplistic view. It may be that measures of social functioning and possibly therefore cognition may be better predictors of physical activity than psychiatric symptomatology per se.

There is an increase in the prevalence of obesity among people with schizophrenia thought to be due in part to the weight enhancing side-effects of medications commonly used to treat the symptoms of schizophrenia. Despite the deleterious health effects associated with obesity and its impact on quality of life and medication compliance, little is known about body composition and energy expenditure in this clinical group. The primary purpose of this thesis was to enhance understanding of body composition and energy expenditure, particularly resting energy expenditure in men with schizophrenia who take atypical antipsychotic medications. Unique to this investigation is the evaluation of clinical tools used to predict body composition and energy expenditure against reference methodologies in men with schizophrenia. Further, given the known links between obesity and physical activity, an additional but less comprehensive component of the thesis was a consideration of total and activity energy expenditure in addition to the interaction between psychiatric symptoms, side-effects of antipsychotic medications and physical activity also occurred as part of this thesis. Collectively, the goals of this thesis were addressed through a series of studies – the first two studies were related to the measurement and characteristics of body composition in men with schizophrenia, while the third and fourth studies were related to the measurement and characteristics of resting energy expenditure in men with schizophrenia. The fifth and sixth studies the utilised doubly labelled water technique to quantify activity and total energy expenditure in a small group of men with schizophrenia and explored the use of accelerometry in this cohort. The final study briefly considered the impact of psychiatric symptoms and self-reported medication side-effects on objectively measured physical activity. In the first study, thirty-one male adults previously diagnosed with schizophrenia and sixteen healthy male controls were recruited. Estimates of body composition derived from an anthropometry-based equation and from bioelectric impedance analysis (BIA) using deuterium dilution as the reference methodology to determine total body water were compared. The study also determined the validity of equations commonly used to predict body composition from BIA in the men with schizophrenia. A further aim was to determine the superiority of either BIA or body mass index (BMI) as an indicator of obesity in this cohort. The inclusion of the control group, closely matched for age, body size and body composition demonstrated that there was no difference in the ability of body composition prediction methods to distinguish between fat and fat-free mass (FFM) in controls and men with schizophrenia when both groups had similar body composition. However this study indicated that an anthropometry-based equation previously used in people with schizophrenia was a poor predictor of body composition in this cohort, as evidenced by wide limits of agreement (25%) and systematic variation of the bias. In comparison, the best predictor of percentage body fat (%BF) in this group was gained when impedance values were used to predict percentage body fat via the equation published by Lukaski et al (1986). Although percentage body fat was underpredicted using the Lukaski et al. (1986) equation, the mean magnitude was relatively small (1.3%), with the limits of agreement approximately 13%. Linear regression analysis revealed that %BF predicted using the Lukaski et al. (1986) equation explained 25% more of the variance in percentage body fat than BMI. Further, this study also indicated that BIA was more sensitive than BMI in distinguishing between overweight and obesity in this cohort of men with schizophrenia. Because of the almost exclusive use of BMI as an indicator of obesity in people with schizophrenia, the level of excess body fat may be in excess of that previously indicated. The second study extended the examination of body composition in men with schizophrenia. In this study, the thirty-one participants with schizophrenia (age, 34.2 ± 5.7 years; BMI, 30.2 ± 5.7 kg/m2) were individually matched with sedentary controls by age, weight and BMI. Deuterium dilution was used to distinguish between FFM and fat mass. The previous study had indicated that while BIA was a suitable group measure for obesity, on an individual level the technique lacked the precision required for investigating body composition in men with schizophrenia. Waist circumference was used as an indicator of body fat distribution. The findings of this study indicated that in comparison with healthy sedentary controls of similar body size and age, men with schizophrenia had higher levels of body fat which was more centrally distributed. Percentage body fat was on average 4% higher and waist circumference, on average 5 cm greater in men with schizophrenia than the sedentary controls of the same age and BMI. Further, this study indicates that the use of BMI to predict body fat in men with schizophrenia will result in greater bias than when it is used to predict body fat in other sedentary men. Commonly used regression equations to predict energy requirements at rest are based on the relationships between weight and resting energy expenditure (REE) and in such equations, weight acts as a surrogate measure of FFM. The objectives of study three were to measure REE in a small group of men with schizophrenia who were taking the antipsychotic medication clozapine and to determine whether REE can be predicted with sufficient accuracy to substitute for the measurement of REE in the clinical and/or research settings. Body composition was determined using deuterium dilution and REE was measured using a Deltatrac Metabolic Cart via a ventilated hood. The male participants, (aged 28.0 ± 6.7 yrs, BMI 29.8 ± 6.8 kg/m2) were weight stable at the time of the study and had been taking clozapine for 20.5 ± 12.8 months, with doses of 450 ± 140 mg/day. Of the six prediction equations evaluated, the equation of Mifflin et al. (1990) with no systematic bias, the lowest bias and the lowest limits of agreement proved to be the most suitable equation to predict REE in this cohort. The overestimation of REE can be corrected for by deducting 160 kcal/day from the predicted REE value when using the Mifflin et al. (1990) equations. However, the magnitude of the error associated with the prediction of REE for an individual is 370 kcal/day. The findings of this study indicate that REE cannot be predicted with sufficient individual accuracy in men with schizophrenia, therefore it was necessary to measure rather than predict REE in subsequent studies. In the fourth study, indirect calorimetry (Deltatrac Metabolic Cart via ventilated hood) and deuterium dilution were used to accurately determine REE, respiratory quotient (RQ) and FFM in 31 men with schizophrenia and healthy sedentary controls individually matched for age and BMI. Data from this study indicated that gross REE was lower in men with schizophrenia than in healthy sedentary controls of a similar age and body size. However, there was no difference between the groups in REE when REE was adjusted for FFM using the mathematically correct method (analysis of covariance with FFM as the covariate). There was however a statistically and clinically significant difference in resting, fasted RQ between men with schizophrenia and controls, suggesting that RQ rather than REE may be an important correlate worthy of further investigation in men with schizophrenia who take antipsychotic medications. Studies five and six involved the application of the doubly labelled water (DLW) technique to accurately determine total energy expenditure (TEE) and activity energy expenditure (AEE) in a small group of men with schizophrenia who had been taking the atypical antipsychotic medication clozapine. The participants were those who took part in study three. The purpose of these studies was to assess the validity of a commercially available tri-axial accelerometer (RT3) for predicting free-living AEE and to investigate TEE and AEE in men with schizophrenia. There was poor agreement between AEE measured using DLW and AEE predicted using the RT3. However, using the RT3 to measure inactivity explained over two-thirds of the variance in AEE. This study found that the relationship between current AEE per kilogram of body weight and change from baseline weight in men taking clozapine was strong although not significant. The sedentary nature of the group of participants in this study was reflected in physical activity levels, (PAL, 1.39 ± 0.27), AEE (435 ±352 kcal/day) and TEE (2511 ± 606 kcal/day) that fell well short of values recommended by WHO (2000) for optimal health and to prevent weight gain. Given the increasing recognition of the importance of sedentary behaviour to weight gain in the general community, further examination of the unique contributing factors such as medication side effects and symptoms of mental illness to activity levels in this clinical group is warranted. The final study used accelerometry (RT3) to objectively measure activity in a group of 31 men with schizophrenia who had been taking atypical antipsychotic medications for more than four months. The purpose of this study was to explore the relationships between psychiatric symptomatology, side-effects of medication and physical activity. Accelerometry output was analysed to provide a measure of inactivity and moderate intensity activity (MIA). The well-validated and reliable standardised clinical interview, the Positive and Negative Syndrome Scale (PANSS) was used as a measure of psychiatric symptoms. Perceived side-effects of medication were assessed using the Liverpool University Neuroleptic Rating Side-Effects Scale (LUNSER). Surprisingly, there was no relationship reported between any measures of negative symptoms and physical inactivity. However, self-reported measures of medication side-effects relating to fatigue, sleepiness during the day and extrapyramidal symptoms explained 40% of the variance in inactivity. This study found significant relationships between some negative symptoms and moderate intensity activity. Despite the expectation that as symptoms of mental illness reduce, inactivity may diminish and moderate intensity activity will increase, it may not be surprising that in practice this is an overly simplistic view. It may be that measures of social functioning and possibly therefore cognition may be better predictors of physical activity than psychiatric symptomatology per se.

Abstract Aim The aim of the study was to examine the capability of accelerometers to estimate energy expenditure during high-intensity complex physical activity patterns. Also, to investigate whether placing the monitor on the hip or wrist influenced its prediction ability. Furthermore, the purpose was also to evaluate if there was a significant difference in the aforementioned estimations using data from one axis compared to all three axis combined.     Method A total of 14 subjects, eight men and six women, mean (SD) age of 26, 4 (5,5) years were recruited for the study. The participants performed standardised aerobic exercise while accelerometer data and oxygen uptake was measured simultaneously. Two triaxial accelerometers (Actigraph GT3X) were worn on the hip and wrist during the experiment. Indirect calorimetry, using Oxycon mobile, was chosen as the criterion measure. Validity was determined by comparing accelerometer counts with estimated energy expenditure (EE) in kcal/min, derived from measured oxygen consumption, using bivariate Pearson correlation, linear regression and stepwise regression analyses. Equations were calculated using each participant’s individual regression analyses.   Results The experiment reveals that GT3x presents a moderate correlation (r= 0, 47) for estimating EE from aerobics when worn on the hip and a weak correlation (r = 0.34) when worn on the wrist. However, when combined with the body mass variable, a strong correlation was found between accelerometer data for the hip and EE (r= 0.73). At both positions the vector magnitude (r = 0.47 for the hip and r = 0.34 for the wrist) yielded stronger correlations compared to just using the Y-axis (r = 0.15 for the hip and r= 0.08 for the wrist).     Conclusions In conclusion, this study found that GT3x was not particularly valid for assessing energy expenditure in high intensity complex activities. Wearing the accelerometer on the hip yielded higher correlations compared to wearing it on the wrist. When using the accelerometer for estimations of EE the Vector magnitude is to prefer before the Y-axis solely.

Research in this thesis has examined the acute and chronic effects of exercise on hunger, energy intake and expenditure. Cross-sectional studies examined the effect of 60 min of moderate-intensity cycling on immediate and subsequent three day energy intake and expenditure in active and inactive men (study one) and women not using hormonal contraceptives (study two) and taking oral contraceptives (study three). Study four examined the effects of 12 weeks of moderate-intensity aerobic exercise on 7-day free-living energy intake and expenditure. A total of 47 men (mean ± SD; age 23.8 ± 4.2 y; body mass index 24.2 ± 3.0 kg-m'2) and 52 women (22.7 ± 3.4 y; 22.1 ± 2.1 kg-m'2)were recruited into four studies. In study one, 60 min of moderate-intensity (50% of maximum oxygen uptake) cycling did not have an effect on hunger or ad libitum lunch energy intake (p > 0.05) but induced an acute (within the experimental day, p = 0.024, d = 0.56) and delayed (third day after the experimental day,/ > = 0.024, < i= 0.80) increase in free-living energy intake in active and inactive participants, respectively with no compensatory changes in freeliving energy expenditure (p > 0.05). Similarly, studies two and three demonstrated that an acute bout of moderate-intensity aerobic exercise does not increase hunger or ad libitum lunch energy intake in active and inactive women {p > 0.05). In study two there were no exercise-induced compensatory responses in free-living energy intake {p > 0.05) whereas in study three, the inactive group decreased their daily energy intake on the first day after the exercise experimental day compared with control (p = 0.002, d = -0.89). No compensatory changes in daily physical activity energy expenditure were observed in these studies (p > 0.05). In study four 12 weeks of moderate-intensity aerobic exercise did not induce changes to weekly free-living energy intake and expenditure (p > 0.05) despite the high inter-individual variability in changes in body composition. Additionally, inactive participants are not able to independently maintain their physical activity behaviour after the end of a supervised exercise intervention. Overall, this research shows that an acute bout of moderate-intensity aerobic exercise did not affect hunger irrespective of sex or habitual physical activity, however the use of oral contraceptives may have heightened appetite in women. Active men were able to compensate for the acute exercise-induced energy deficit by increasing their energy intake quicker (within the experimental day) than inactive men (third day after the experimental day). In women, no clear relationship was apparent. Moreover, an acute bout of exercise did not elicit compensatory changes in physical activity in men and women. These findings enhance the knowledge of how an acute bout of exercise affects immediate and subsequent energy intake and expenditure in active and inactive men and women but more work is needed to confirm and explore the potential causal mechanisms.

Older adults with chewing and swallowing difficulties frequently report increased fatigue and effort, or energy expenditure, during eating. Energy is defined as the ability to perform work. It is most accurately measured through an examination of the gaseous composition of inhaled and exhaled air at rest and during activity using laboratory-based indirect calorimetry. There is a need for a valid measure of energy expenditure that can be used to document the effort involved in eating and swallowing in natural contexts. The purpose of the current study was to determine the concurrent validity of the portable SenseWear® system compared to indirect calorimetry during a simulated eating task. Nineteen university students served as participants. Each was connected simultaneously to indirect calorimetry and SenseWear® systems. Energy expenditure was obtained while participants chewed gum and swallowed repeatedly. Pearson product-moment correlations showed a close relationship (p < 0.05) between the two measurement methods. Mean Mid-Arm Muscle Circumference measures also correlated positively with both measurement methods, reflecting the influence of body mass on energy expenditure. Results support the use of the SenseWear® system to measure energy expenditure in chewing and swallowing in natural contexts, particularly for adults with chewing and swallowing difficulties.
Thesis (M.A.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders.

Seasonal changes in the daily energy expenditure (DEE) of captive northern fur seals (Callorhinus ursinus) and key components of their energy budget (cost of resting metabolism, thermoregulation, activity and growth) were examined to elucidate potential reasons for the species’ population decline in the wild. The average DEE of 6 females was 527.8 ± 65.7 kJ kg-¹ d-¹ and fluctuated seasonally (~20% greater in the fall than in the winter). Resting metabolism also changed significantly with season, and was higher in the fall (potentially due to molting or as preparation for migratory activity). While resting metabolism was the largest component of the DEE (~80% on average), it did not follow the same seasonal trend as DEE, and therefore was not the source of the seasonal variation in DEE. Cost of activity was the second major component of DEE and may explain the observed seasonal variations. Energetic costs associated with thermoregulation appeared to be negligible. The northern fur seals were thermally neutral in all seasons for all water temperatures tested (2 °C – 18 °C), except during the summer when immersed in 2 °C water. Comparing this broad thermal neutral zone to the average sea surface temperatures encountered by fur seals in the wild during annual migrations indicates that fur seals can likely exploit a large geographic area without added thermal metabolic costs. While the direct energetic costs of growth appeared to be negligible compared to DEE, the higher growth rates in the summer and elevated resting metabolism in the fall suggests that inadequate nutrition could have greater negative effects during these seasons. Two alternative proxies for measuring energy expenditure were tested and calibrated against respirometry for potential application to wild individuals. The doubly labeled water (DLW) method over-estimated DEE by 13.1 ± 16.5% compared to respirometry. In comparison, accelerometry over-estimated DEE, using fine time scale intervals of 60 and 15 min, by an average of 5.4 ± 29.3% and 13.8 ± 39.5%, respectively. Importantly, seasonal effects (and time of day for accelerometry) must be accounted for when estimating energy expenditure from measures of DLW and acceleration in free-swimming northern fur seals.

The overarching aim of this thesis was to enhance the prediction of physical activity energy expenditure (PAEE) in military personnel; specifically, improving accuracy and minimising obtrusiveness. The first experimental chapter provided a thorough assessment of the reliability and validity of the 3DNX accelerometer. Within unit reliability (CVintra) physical activity counts (PAC) was 0.0-8.9% in all axes in a mechanical setting. Between unit reliability (CVinter) did not exceed 4.5%.The relationship between PAC and acceleration was r2 = 0.99 and standard error of the estimate (SEE) of 6 counts∙5s-1. During treadmill exercise, the relationship between and PAC was linear (walking, r2 =0.65, SEE = 1.42 ml·kg-1·min-1; running, r2 =0.62, SEE = 3.63 ml·kg-1·min-1). 3DNX PAC output was valid and reliable when subjected to a physiologically relevant range of mechanically generated accelerations and yielded a linear relationship with during treadmill walking and running. Chapter 7 investigated the effect of anatomical placement on PAC in order to find the most suitable wear location. Hip and back placements returned similar reliability (CVintra = 3.0% and 2.8% respectively). Hip PAC were higher (p < 0.01) for walking with no differences observed for running. Indices of adiposity were related to hip PAC. Regression analysis revealed hip and back PAC as significant predictors of . Back PAC was the least variable placement. Supraspinale skinfold thickness explained 15% additional variance in to PAC and reduced SEE. In Chapter 8, three available devices were compared to doubly labelled water (DLW) for the prediction of free living PAEE using a user-oriented approach. All devices underestimated PAEE. Actiheart-derived PAEE was not different from DLW. However, the wide absolute limits of agreement (LoA) indicated large individual error which was attributed to the use of group rather than individual calibration. 3DNX and GT3X PAEE predictions were different from DLW however LoA were narrower indicating the possibility of applying a correction factor in future. Chapter 9 was an amalgamation of ten independent cohorts in an attempt to produce a military-specific multivariate model for the prediction of energy expenditure (EE). Stringent data reduction techniques were applied to a highly compliant dataset. Allometric models showed PAC, height and body mass were related to total energy expenditure (TEE) (p < 0.01). For models predicting TEE, PAC explained 4 % of the variance. For models predicting PAEE, PAC accounted for 6 % of the variance. The small amount of variance explained by PAC was likely due to the inability of accelerometers to detect EE as a result of day-to-day military activities such as load carriage. Such small portions of explained variance indicate that traditional accelerometry techniques are inadequate for use in military populations. In Chapter 10, an alternative approach to characterising military-specific activities was explored due to the minor contribution of PAC to PAEE prediction in Chapter 9. Accelerometer raw signal (100 Hz) was used to develop a classification model which aimed to discriminate load carriage (LC) from unloaded ambulation during an occupationally relevant protocol (2-hours, 6.4km∙hr-1, 25kg load). Fast Fourier transformation showed differences in the frequency distribution of the signal between conditions; caused by differences in gait parameters. Load carriage was detected in 97.2% of 1-minute samples with reduced classification accuracy during the last 30 minutes. Fatigue was suggested as a cause of misclassification; indicated by an upwards drift in and RPE across time. In conclusion, accelerometer PAC is a weak contributor to the prediction of energy expenditure in military populations. Accuracy could be improved by detection of load bearing activities which is feasible given the advancement in technology and analysis techniques. New technologies such as optical interferometrics could be integrated into existing military equipment to detect heartbeat and respiration; providing data regarding the physiological strain of training and operations.

The subject of energy balance in humans has been well researched over the past one hundred years. However, the reason why some individuals are better at regulating their body weight than others is still far from clear. The aim of this study was to further investigate the relationship between energy expenditure and energy intake under varying conditions. The first phase involved a set of three experiments. Experiment 1 (n=15, men) was based on expending energy through exercise (EX)(837 kJ on a cycle-ergometer), exercise in the cold (11-13°C) (CES), exercise with prior caffeine (200mg) ingestion (CAFF) and a control condition (CS). Experiment 2 compared two levels of energy expenditure with a control (CT) in 12 men (a) 837 kJ (LIE) and (b) 2510kJ (HIE). In experiment 3, subjects undertook two tests: an exercise session 837 kJ and a control condition. Subjects in experiment 3 were categorised into three groups according to their 8MI: lean (L, n=6), normal weight (NW, n=13) and overweight (OW, n=13). Analysis of data from experiment 1 showed no significant difference in energy intake for the four conditions: 5.7(±1.2), 5.7(±1.6), 5.6(±1.4) and 6.0(±1.6) MJ for CS, EX, CAFF and CES conditions respectively. A significant increase in energy intake only in the HIE condition compared with the CT (p =0.028) was observed in experiment 2. In experiment 3, energy intake for the Land NW subjects were in concordance between the exercise and control conditions (rs=0.943, p =0.005 and rs=0.797, p=0.001 respectively) but not for the OW subjects (rs= 0.258, p=0.394). A significant increase was observed in 12-hour energy intake between the test conditions and habitual for the OW subjects (p=0.014) but not for the Land NW subjects. The second phase investigated the effect of hot peppers on energy expenditure after ingestion - post-prandial thermogenesis (PPT) in 17 men. Findings confirmed that a significant increase in PPT (27%) occurred after a hot pepper meal compared with the control (p