A comparison of the metabolic effects of sustained strenuous activity in polar environments on men and women

This study investigates differences in pre- to post-expedition energy expenditure, substrate utilisation and body composition, between the all-male Spear17 (SP-17) and all-female Ice Maiden (IM) transantarctic expeditions (IM: N = 6, 61 days, 1700 km; SP-17: N = 5, 67 days, 1750 km). Energy expenditure and substrate utilisation were measured by a standardised 36 h calorimetry protocol; body composition was determined using air displacement plethysmography. Energy balance calculation were used to assess the physical challenge. There was difference in the daily energy expenditure (IM: 4,939 kcal day−1; SP-17: 6,461 kcal day−1, p = 0.004); differences related to physical activity were small, but statistically significant (IM = 2,282 kcal day−1; SP-17 = 3,174 kcal day−1; p = 0.004). Bodyweight loss was modest (IM = 7.8%, SP-17 = 6.5%; p > 0.05) as was fat loss (IM = 30.4%, SP-17 = 40.4%; p > 0.05). Lean tissue weight change was statistically significant (IM = − 2.5%, SP-17 = + 1.0%; p = 0.05). No difference was found in resting or sleeping energy expenditure, normalised to lean tissue weight (p > 0.05); nor in energy expenditure when exercising at 80, 100 and 120 steps min−1, normalised to body weight (p > 0.05). Similarly, no difference was found in the change in normalised substrate utilisation for any of the activities (p > 0.05). Analysis suggested that higher daily energy expenditures for the men in Spear-17 was the result of higher physical demands resulting in a reduced demand for energy to thermoregulate compared to the women in Ice Maiden. The lack of differences between men and women in the change in energy expenditure and substrate utilisation, suggests no sex difference in response to exposure to extreme environments

Laboratory Approaches to Studying Occupants

Laboratories offer the possibility to study occupant behavior in a very detailed manner. A wide range of indoor environmental scenarios can be simulated under precisely controlled conditions, and human subjects can be selected based on pre-defined criteria. The degree of control over experiments is high and a large number of physical, physiological, and psychological quantities can be monitored. This chapter gives an overview of various types of test facilities in the world and their main features in terms of experimental opportunities. It then presents typical technical equipment and sensor technologies used in laboratory environments. Finally, questions on appropriate laboratory design and experimental set-ups are discussed. One conclusion is that, in spite of many advantages, there are limits to investigating occupant behavior in a laboratory’s “artificial” environment, in part due to the fact that subjects always feel observed to some extent. However, valuable results can be achieved if the specific opportunities of laboratories are utilized both by appropriate design and precise experiments during operation

Energy, substrate and protein metabolism in morbid obesity before, during and after massive weight loss

OBJECTIVE: To investigate the effect of surgically induced weight loss on energy, substrate and protein metabolism of morbidly obese patients. DESIGN: A prospective, clinical intervention study of morbidly obese patients before and after surgical treatment. SUBJECTS: Eight morbidly obese patients (BMI 47.88 +/- 7.03). METHODS: Total energy expenditure (TEE; doubly labeled water method), sleeping metabolic: rate (SMR; respiration chamber), body composition (deuterium oxide component of doubly labeled water), substrate metabolism (48 h dietary records, 48 h urine collection and gaseous exchange in the respiration chamber) and whole body protein turnover (primed-continuous infusion of L-[1-C-13]-leucine) were measured before, 3 and 12 months after vertical banded gastroplasty (VBG). RESULTS: The TEE decreased as a result of a decreased SMR (64%) and non-SMR (36%; P = 0.0011, SMR as a function of fat-free mass (FFM) decreased after weight loss (P <0.05). The physical activity index (PAI), defined as TEE/SMR, was low and was not influenced by weight loss. Protein and carbohydrate oxidation decreased significantly after VBG (P <0.05), although 3 months after VBG protein oxidation did not decrease enough to prevent loss of FFM. The energy used for protein turnover was approximately 24% of SMR and did not change after weight loss. CONCLUSIONS: Compensatory processes that oppose weight loss of morbidly obese patients exist, as demonstrated by the disproportional reduction of SMR, and a low PAI, Protein turnover is not a major contributor to the disproportional reduction of SMR

Effect of dietary restraint during and following pegylated recombinant leptin (PEG-OB) treatment of overweight men

Effect of dietary restraint during and following pegylated recombinant leptin (PEG-OB) treatment of overweight men. Lejeune MP, Hukshorn CJ, Saris WH, Westerterp-Plantenga MS. Department of Human Biology, Maastricht University, Maastricht, The Netherlands. [email protected] OBJECTIVE: To examine the effect of dietary restraint during and following pegylated recombinant leptin (PEG-OB protein) treatment in overweight men. DESIGN: A randomized double-blind placebo-controlled trial in 24 overweight men (BMI: 28.8+/-0.3 kg/m(2); age: 34.8+/-0.9 y). PEG-OB protein (80 mg) or placebo was administered subcutaneously weekly for 6 weeks, combined with a 2.1 MJ/day energy restriction program. Dietary restraint was determined by the Three-Factor Eating Questionnaire before and after treatment, and after 8 weeks follow-up. RESULTS: During treatment dietary restraint increased, and general hunger, resting energy expenditure and respiratory quotient decreased similarly in the PEG-OB and the placebo group. With PEG-OB treatment, additional weight loss (P<0.03) was observed. During 8 weeks follow-up, body weight increase was larger in the PEG-OB group compared to placebo (P<0.05), and body weight regain was faster. Body weight regain was inversely correlated with the increase in cognitive dietary restraint during treatment (PEG-OB group: r(2)=0.49, P<0.02; placebo group: r(2)=0.60, P=0.01). CONCLUSION: Although treatment with PEG-OB protein led to a greater body weight loss relative to placebo, weight maintenance thereafter was mainly supported by dietary restraint, which was more effective in the placebo-treated group, resulting in a slower regain of body weight

The effects of 2-week ingestion of (−)-hydroxycitrate and (−)-hydroxycitrate combined with medium-chain triglycerides on satiety, fat oxidation, energy expenditure and body weight

: Int J Obes Relat Metab Disord 2001 Jul;25(7):1087-94 Related Articles, Books, LinkOut The effects of 2-week ingestion of (--)-hydroxycitrate and (--)-hydroxycitrate combined with medium-chain triglycerides on satiety, fat oxidation, energy expenditure and body weight. Kovacs EM, Westerterp-Plantenga MS, Saris WH. Department of Human Biology, Maastricht University, Maastricht, The Netherlands. [email protected] OBJECTIVE: Assessment of the effect of 2-week supplementation with (--)-hydroxycitrate (HCA) and HCA combined with medium-chain triglycerides (MCT) on satiety, fat oxidation, energy expenditure (EE) and body weight (BW) loss. DESIGN: Three intervention periods of 2 weeks separated by washout periods of 4 weeks. Double-blind, placebo-controlled, randomised and cross-over design. SUBJECTS: Eleven overweight male subjects (mean+/-s.d.; age, 47+/-16 y; body mass index, 27.4 +/- 8.2 kg/m(2)). INTERVENTION: Subjects consumed three self-selected meals and four iso-energetic (420 kJ) snacks daily with either no supplementation (PLA), 500 mg HCA (HCA) or 500 mg HCA and 3 g MCT (HCA+MCT). Each intervention ended with a 36 h stay in the respiration chamber. RESULTS: There was a significant BW loss during the 2 weeks of intervention (PLA, -1.0 +/- 0.4 kg, P<0.05; HCA, -1.5 +/- 0.5 kg, P<0.01; HCA+MCT, -1.3 +/- 0.2 kg, P<0.001), but this reduction was not different between treatments. 24 h EE (PLA, 11.8 +/- 0.2 MJ; HCA, 11.7 +/- 0.1 MJ; HCA+MCT, 11.5 +/- 0.1 MJ), 24 h RQ (0.85 +/- 0.00 in all treatments) and the area under the curve of the appetite-related parameters were not different between treatments. CONCLUSION: Two-week supplementation with HCA and HCA combined with MCT did not result in increased satiety, fat oxidation, 24 h EE or BW loss compared to PLA, in subjects losing BW