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Background: Adaptive thermogenesis (AT) is the fat-free mass (FFM)-independent reduction of resting energy expenditure (REE) to caloric restriction (CR). AT attenuates weight loss and favors weight regain. Its variance, dynamics, and control remain obscure. Objectives: Our aims were to address the variance and kinetics of AT, its associations with body composition in the context of endocrine determinants, and its effect on weight regain. Design: Thirty-two nonobese men underwent sequential overfeeding (1 wk at +50% of energy needs), CR (3 wk at 250% of energy needs), and refeeding (2 wk at +50% of energy needs). AT and its determinants were measured together with body composition as assessed with the use of quantitative magnetic resonance, whole-body MRI, isotope dilution, and nitrogen and fluid balances. Results: Changes in body weight were +1.8 kg (overfeeding), 26.0 kg (CR), and +3.5 kg (refeeding). CR reduced fat mass and FFM by 114 and 159 g/d, respectively. Within FFM, skeletal muscle (25%), liver (213%), and kidneys (28%) decreased. CR also led to reductions in REE (2266 kcal/d), respiratory quotient (215%), heart rate (214%), blood pressure (27%), creatinine clearance (212%), energy cost of walking (222%), activity of the sympathetic nervous system (SNS) (238%), and plasma leptin (244%), insulin (254%), adiponectin (249%), 3,5,3#-tri-iodo-thyronine (T3) (239%), and testosterone (211%). AT was 108 kcal/d or 48% of the decrease in REE. Changes in FFM composition explained 36 kcal, which left 72 kcal/d for true AT. The decrease in AT became significant at #3 d of CR and was related to decreases in insulin secretion (r = 0.92, P , 0.001), heart rate (r = 0.60, P , 0.05), creatinine clearance (r = 0.79, P , 0.05), negative fluid balance (r = 0.51, P , 0.01), and the free water clearance rate (r = 20.90, P , 0.002). SNS activity and plasma leptin, ghrelin, and T3 and their changes with CR were not related to AT. Conclusion: During early weight loss, AT is associated with a fall in insulin secretion and body fluid balance. This trial was registered at clinicaltrials.gov as NCT01737034. [ABSTRACT FROM AUTHOR]

Background. The purpose of this study was to assess the post-exercise O2 uptake and heart rate response in patients with heart failure (HF) in comparison to healthy individuals. Methods and Results. Exercise testing of all subjects was conducted according to the RITE-protocol. The study subjects were classified according to their peak oxygen uptake (peak VO2) in four groups: healthy individuals with a peak VO2 >22 mL/kg/min (group 1, n: 50), and patients with HF and a peak VO2 of 18-22 mL/kg/min, (group 2, n: 48), 14-18 mL/kg/min (group 3, n: 57), and <14 mL/kg/min (group 4, n: 31). Both peak VO2 and HR declined more slowly in the patients with HF than in the normal subjects. Recovery of VO2 and HR followed monoexponential kinetics in the early postrecovery phase. This enabled the determination of a time constant for both HR and VO2 (TC VO2 and TC HR). From group 1 to 4 there was a prolongation of the time constant for VO2 and HR: TC VO2 (group 1: 110±34, group 2: 197±43, group 3: 238±80, and group 4: 278±50 sec), and TC HR (group 1: 148±82, group 2: 290±65, group 3: 320±58, and group 4: 376±55 sec). Conclusion. The rate of decline of VO2 and HR in the early post-exercise phase is inversely related to the peak VO2. The time constant for oxygen uptake (TC VO2) and heart rate (TC HR) might prove a useful parameter for more precise monitoring and grading of HF. [ABSTRACT FROM AUTHOR]

Increased adverse health effects in older subjects due to exposure to ambient air pollutants may be related to the inflammatory response induced by these contaminants. The aim of this study was to assess airway and systemic inflammatory responses in older healthy subjects to a controlled experimental exposure with spark-generated elemental carbon black ultrafine particles (cbUFPs) and ozone (O 3 ). Twenty healthy subjects, age 52-75 years, were exposed on three occasions separated by at least 8 weeks. The exposures to filtered air (FA), to cbUFP (50 μg/m 3 ), or to cbUFP in combination with 250 ppb ozone (cbUFP + O 3 ) for 3 h with intermittent exercise were performed double blind, and in random order. Sputum and blood samples were collected 3.5 h after each exposure. Exposure to cbUFP + O 3 significantly increased plasma club cell protein 16 (CC16), the number of sputum cells, the number and percent of sputum neutrophils, and sputum interleukin 6 and matrix metalloproteinase 9. Exposure to cbUFP alone exerted no marked effect, except for an elevation in sputum neutrophils in a subgroup of 13 subjects that displayed less than 65% sputum neutrophils after FA exposure. None of the inflammatory markers was correlated with age, and serum cardiovascular risk markers were not markedly affected by cbUFP or cbUFP + O 3 . Exposure to cbUFP+O 3 induced a significant airway and systemic inflammatory response in older healthy volunteer subjects. The effects induced by cbUFP alone suggest that the inflammation was predominantly mediated by O 3 , although one cannot rule out that the interaction of cbUFP and O 3 played a role.

Objective: Previous studies have shown that migration and acculturation lead to higher blood pressures and a higher prevalence of cardiovascular diseases. Heightened cardiovascular reactivity is considered as a risk factor for cardiovascular diseases. Therefore, the purpose of the present study was to examine cardiovascular reactivity in young and healthy second-generation Turkish migrants to Germany., Method: Forty-one Turkish and 20 German male students worked on a mental arithmetic task for 6 min and underwent the cold pressor test for 90 s. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were taken in intervals of 2 min at baseline and during task periods. Stroke volume (SV), cardiac output (CO), preejection period (PEP), and total peripheral resistance (TPR) were registered continuously by impedance cardiography. The Turkish volunteers were divided into weak and advanced acculturated migrants based on self-ratings given in a questionnaire., Results: Advanced acculturated Turkish students showed greater HR and CO increases and greater PEP and TPR decreases to the mental arithmetic task than Germans or weak acculturated Turkish students. No group differences were found for the cold pressor test., Conclusion: Migrants' acculturation is associated with an enhanced beta-adrenergic activation pattern of the sympathetic nervous system that might put them at greater risk with regards to essential hypertension and coronary heart disease., (Copyright 2002 Elsevier Science Inc.)