Watching television or listening to music during exercise has been shown to increase the enjoyment of the activity and decrease fatigue for some people. However, it is currently unknown how these stimuli during an exercise session play a role in postexercise energy intake and/or physical activity energy expenditure (PAEE). The purpose of this thesis was to examine the effects of watching television or listening to music while exercising on post-exercise energy intake and expenditure in male adolescents. The study consisted of a randomized crossover design involving 24 male adolescents aged 12 to 17 years. The participants completed three experimental sessions that included walking/jogging on a treadmill at 60% of their heart rate reserve for 30 minutes while watching television, listening to music, or exercising with no other stimulus (control). Following the exercise sessions participants were given an ad libitum lunch and were asked to record their food intake for the remainder of the day. An Actical accelerometer was used to assess PAEE until bedtime. The primary outcome measure was post-exercise energy intake and energy expenditure. Results showed that exercising while watching television or listening to music did not significantly affect postexercise energy intake or energy expenditure. Walking/jogging on a treadmill was found to be more enjoyable while watching television than with no stimulus present (p=0.03). Ratings of perceived exertion were not significantly different between conditions. Overall, our results suggest that watching television or listening to music while exercising does not impact post-exercise energy intake or expenditure in male adolescents, which may have positive implications for adolescents who may need additional motivation to exercise.

The aim of this thesis was to evaluate changes in resting energy expenditure (REE) in ten lactating women between three weeks and nine months postpartum to find out whether there is any link with the parameters presented in this study. Measurements were taken at four intervals. At three weeks and at three, six and nine months postpartum. They were taken in the morning after a night fast (12 hours) and used indirect calorimetry with a canopy in awake lying subjects for approximately 25 minutes. The room was shaded with minimal noise with a temperature around 20 řC. Urine was collected over 24 hours and was examined for nitrogen concentration. The median REE was 1591,86 kcal/day at 3 weeks postpartum, 1398,08 kcal/day at 3 months, 1401,78 kcal/day at 6 months and 1455,03 kcal/day at 9 months postpartum. Values of REE per kilogram of body weight are 21,8 ± 0,36 kcal/kg and are consistent throughout the measurement period. The oxidation of lipids was dominant compared to other substrates and the lowest was oxidation of sacharides during the whole observation period. Correlations were found in parameters such as, body weight and REE per kilogram, breast milk and respiratory quotient (RQ), length of gravidity with RQ/ volume of exhaled carboxydioxide/ volume of inhaled oxygen. Another was between protein...

Background The aim of diploma thesis was to evaluate resting energy expenditure (REE) and substrate oxidation in Czech lactating women and their relation to measured anthropometric parameters. Methods The indirect calorimetry was used to asses REE. Subsequently, the oxidation of substrates was calculated. At the same time were measured anthropometric parameters of breastfeeding women. Then the correlation was investigated. The total amount of examination were three times. First was in the time three weeks after birth, the second one was three months postpartum and the last was six months after birth. Results The mean values of REE in lactating women were 1577±93 kcal/day in the time of three weeks after birth. Three months after birth it was 1622±140 kcal/day. Six months after birth it was 1545±80 kcal/day. Significant positive correlation was proved between REE and triceps skinfold thickness (r = 0,98; P < 0,05) and also chest circumference (r = 0,99; P < 0,05). Both were three weeks after birth. Breastfeeding women had a value of lipid oxidation 60 % of substrate oxidation three weeks postpartum, which decreased to 46 % three months postpartum due to sharp increase (from 8 % to 18 %) of carbohydrate oxidation value. This increase could correspond to the preferential use of glucose by the mammary...

To measure physical activity in a wheelchair user is important. Disabled people have been found to be less active and it has negative health implications. By relating to ones own physical activity in concrete form it is easier to reinforce a positive attitude towards being physically active. The aim of this thesis is to show how a system can be built, that is able to collect measurements from sensors, with usability in mind. The system consists of software that integrates an iPhone, Apple Watch and a Tacx rotation sensor mounted on a wheelchair. With the help of a physics model these measurements can estimate energy expenditure of a wheelchair user. The system was tested with four participants performing subjectively decided low, moderate and vigorous physical activity while the system collected data. In terms of absolute energy expenditure the system was inaccurate. On the other hand, correlations were found between the calculated energy expenditures and physical activity. Using measurements from the rotations sensor a correlation of 0.7315 was found between the calculated energy expenditure and physical activity, a correlation of 0.5385 using measurements from the GPS and a correlation of 0.6452 using measurements from Apples own proprietary algorithm. The created system is a promising prototype towards objective measurement of physical activity in wheelchair users.

A lower resting energy expenditure (REE) has been suggested to partially explain the disproportionate prevalence of overweight/obesity among black African women, yet no studies have investigated the REE of South African (SA) children. Similarly, physical activity (PA) as a modifiable factor related to childhood energy expenditure is under-researched in the local context. The study determined the relationship between sex and population group (determinant factors), on the one hand, and REE and PA (outcomes) of 6–9-year-old SA children attending two primary schools in the City of Tshwane metropolitan area, on the other, taking phenotypic characteristics as confounders (mediating factors) and the study context into account. In a cross-sectional study with quota sampling, the REE of 6–9-year-old children attending two urban schools in SA was measured with indirect calorimetry (IC), and PA with a pedometer. Multifrequency bioelectrical impedance analysis was used to assess body composition (BC) (fat-free mass [FFM], FFM index, fat mass [FM] and FM index). Multivariate regression was used to calculate REE and PA adjusted for phenotypic confounders (z-scores of weight-for-age, height-for-age and body mass index-for-age, and BC). Sex and population differences in REE and PA (measured and adjusted) were determined with two-way ANOVA. Ninety-four healthy children (59.6% girls; 52.1% black African) with similar socio-economic status and access to PA participated in the study. Despite variations in BC, sex differences in REE were not significant (41 kcal/day ≈ 172 kJ/day; P = 0.375). The REE in black African participants was significantly lower than in their white counterparts (146 kcal/day ≈ 613 kJ/day; P = 0.002). When adjusting for BC, population differences in REE declined, especially after adjustment for FFM (91 kcal/day ≈ 382 kJ/day; P = 0.039), but remained clinically significant. Average steps/day in girls (10212 [9519;10906]) was lower than in boys (11433 [10588;12277]) (P = 0.029), and lower in black African (9280 [8538;10022]) than in white (12258 [11483;13033]) (P < 0.001) participants. No significant relationship (r = 0.05; P = 0.651) was observed between REE and PA. Within the context of a similar SES and PA environment, the REE and PA of black African children was lower than white. Differences in REE between sexes were not significant, but girls had a lower PA than boys. / Thesis (PhD (Dietetics))--University of Pretoria, 2020. / South African Sugar Association project No. 260 / Human Nutrition / PhD (Dietetics) / Unrestricted

Recent findings suggest that leptin may be regulated in response to abrupt changes in energy homeostasis. Therefore, it is conceivable that transient changes in energy balance induced by exercise may also regulate leptin synthesis and secretion. As such, we hypothesized that acute increases energy expenditure (i.e. exercise), may regulate leptin concentrations in obese individuals. Fifteen healthy obese males underwent either a single exercise session of moderate intensity (58.4 % ± 4.0 of VO2max) for 60 min (n=8), or served as controls (n=7). The exercise session elicited an energy expenditure of 567±80 Kcal. No significant changes in plasma leptin (pre 23.5± 30.2; post 24.3± 34.3; 24h-post 34.9± 66.6; 48h-post 33.8±64.0 ng/ml), or insulin levels (pre 16.1± 9.2 vs. post 8.1± 9.1; 24h-post 14.3± 9.9; 48h-post 13.8± 10.2 ?U/ml) were detected immediately after the intervention. Baseline plasma leptin levels were positively correlated with BMI (r=0.65; p<0.01), body weight (r=0.64; p<0.01), % body fat (r=0.90; p<0.01) and were negatively correlated with VO2max (r=-0.82; p<0.01). The results of the present study suggest that acute exercise of moderate intensity and duration may not affect leptin concentration.

No description available.

Mutations in the melanocortin 4 receptor (MC4R) are the most frequent cause of monogenetic forms of human obesity. Despite its importance, the MC4R signaling pathways and transcriptional regulation that underly the melanocortin pathway are far from being fully understood. The transcription factor Nescient Helix Loop Helix 2 (Nhlh2), is known to influence the melanocortin pathway. It regulates the transcription of genes by binding to the E-Box binding sites present in the promoter region. Here in this dissertation, Nhlh2's role as a transcriptional regulator of Mc4r and the effects of deletion of Nhlh2 on peripheral energy expenditure, glucose homeostasis and fatty acid oxidation are reported. To investigate the transcriptional mechanisms of Mc4r and the involvement of Nhlh2, gene expression analysis, DNA-protein binding, transactivation assays, and SiRNA induction were used. We show that Nhlh2 regulates the transcription of Mc4r by binding to the three E-Boxes present on the promoter at -553, -361 and +47. Further, SiRNA knockdown of Nhlh2 in the N29/2 cell line depresses Mc4r expression which suggests the requirement of Nhlh2 for Mc4r transcription. Development of adult onset obesity in the absence of evident hyperphagia questions the ability of mice which lacks Nhlh2 (N2KO) to utilize energy substrate efficiently. To test the effect of deletion of Nhlh2 in N2KO, body composition analysis, tissue specific characterization, fatty acid oxidation and glucose and insulin homeostasis were assessed. N2KO mice have a higher fat content than WT at the age of 12 weeks. There are architectural differences in adipose tissue of N2KO. White adipose tissue (WAT) shows infiltration of macrophages, and increased mRNA and serum levels of interleukin 6 which suggests the presence of a systemic inflammatory state in the N2KO mice. Sympathetic nervous system tone is reduced in both brown adipose tissue (BAT) and WAT, as evidenced by gene expression analysis, and this may be because of overall reduced melanocortinergic tone in N2KO mice. N2KO mice have an impaired glucose tolerance on the basis of their late glucose clearance on glucose (non-significant) and insulin (significant) challenges. Fatty acid oxidation (FAO) is higher in red fibers of skeletal muscle, and the respiratory exchange ratio (RER) is lower in N2KO, which is indicative of using fat as a preferential energy source. Increased expression of genes involved in the lipid metabolism in skeletal muscle and liver supports the RER and FAO, and are indicative of high turnover of lipids in N2KO. Findings from these studies implicate Nhlh2 as a transcriptional regulator of Mc4r which has a direct relevance to the ever increasing epidemic of obesity. Characterization of N2KO mice sheds light on the adult onset obesity phenotype. Knowledge gained from these findings will help us understand the monogenetic form of obesity more completely and could lead to the design of improved pharmacological therapies that target Nhlh2 or Mc4r or modify physical activity behavior. / Ph. D.

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.

2 pp. / The energy content of food is measured in calories. The number of calories, or energy, an athlete needs to maintain weight depends upon: age, body weight, gender, Resting Energy Expenditure (REE) and physical Activity Energy Expenditure (AEE) levels.