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Clinically significant weight loss is associated with health benefits for overweight and obese adults. Participation in adequate amounts of physical activity is critical for weight maintenance. However, the recommended amount of physical activity needed to promote weight maintenance is based primarily on retrospective studies that quantified physical activity levels through questionnaires which tend to overestimate physical activity levels. In addition, the present literature has provided little data on the impact of these physical activity levels on cardiovascular and diabetes risk factors, which may have equal or more clinical importance than weight changes. The Prescribed Exercise to Reduce Recidivism After Weight Loss-Pilot (PREVAIL-P) study will evaluate the effect of aerobic exercise training amount on weight maintenance following clinically significant weight loss in overweight and obese adults (BMI 25–40 kg/m2) age 30–65 years. Participants (N = 39) will complete a 10-week OPTIFAST® weight loss program with supervised aerobic exercise training. Individuals who achieve ≥7% weight loss from baseline will be subsequently randomized to levels of aerobic training consistent with physical activity recommendations (PA-REC) or weight maintenance recommendations (WM-REC) for 18 additional weeks. The primary outcome of the PREVAIL-P study will be change in weight from the completion of OPTIFAST® program to the end of the study. Notable secondary measures include changes in clinically relevant cardiometabolic risk factors between study groups (e.g. blood lipids concentrations, oral glucose tolerance, arterial stiffness). This pilot study will be used to estimate the effect sizes needed for a randomized controlled trial on this topic.

Poor suppression of lipolysis and blunted increase in blood flow following meal ingestion in obese adults may indicate resistance to the antilipolytic action of insulin. Exercise may be used to normalize lipolytic responses to food intake by increasing insulin sensitivity. PURPOSE: To determine if acute bouts of aerobic exercise and/or excise training alter lipolytic and blood flow responses to food intake in lean (LN) and obese (OB) children. METHODS: Sixty-five children (9–11 yrs) were randomized into acute exercise (EX: 16 LN and 28 OB) or control (CON: 9 LN and 12 OB) groups that exercised (EX), or rested (CON) between standardized breakfast and lunch. Microdialysis probes were inserted into the subcutaneous abdominal adipose tissue to monitor interstitial glycerol (lipolysis) and blood flow. Changes in interstitial glycerol and nutritive flow were calculated from dialysate samples before and after each meal. A subgroup (OB=15 and LN=9) from the acute exercise group underwent 16 weeks of aerobic exercise training. RESULTS: Poor suppression of lipolysis and a blunted increase in adipose tissue nutritive blood flow in response to breakfast was associated with BMI percentile (r=0.3, p

OBJECTIVE. To examine the influence of physical activity (PA) and sedentary behavior in modifying cardiometabolic risk following Roux-en-Y gastric bypass (RYGB) surgery. SETTING. University of Pittsburgh Medical Center and East Carolina University bariatric surgery centers. METHODS. Data were analyzed from 43 women and 7 men who completed testing at 1–3 months post RYGB surgery and again at 9 months post-surgery. Outcomes measured included PA level (min/day), steps/day, sedentary time, and body composition. Insulin sensitivity (S(I)) was determined with an intravenous glucose tolerance test. Body weight and blood lipid profiles were also obtained. RESULTS. Patients reduced body mass index (BMI) by a mean of −8.0±3.4 kg/m(2) (P

Background African Americans have a disproportionate prevalence and incidence of type 2 diabetes compared with Caucasians. Recent evidence indicates that low cardiorespiratory fitness (CRF) level, an independent risk factor for type 2 diabetes, is also more prevalent in African Americans than Caucasians. Numerous studies in Caucasian populations suggest that vigorous exercise intensity may promote greater improvements in CRF and other type 2 diabetes risk factors (e.g., reduction of glucose/insulin levels, pulse wave velocity, and body fat) than moderate intensity. However, current evidence comparing health benefits of different aerobic exercise intensities on type 2 diabetes risk factors in African Americans is negligible. This is clinically important as African Americans have a greater risk for type 2 diabetes and are less likely to meet public health recommendations for physical activity than Caucasians. The purpose of the HI-PACE (High-Intensity exercise to Promote Accelerated improvements in CardiorEspiratory fitness) study is to evaluate whether high-intensity aerobic exercise elicits greater improvements in CRF, insulin action, and arterial stiffness than moderate-intensity exercise in African Americans. Methods/Design A randomized controlled trial will be performed on overweight and obese (body mass index of 25–45 kg/m2) African Americans (35–65 years) (n = 60). Participants will be randomly assigned to moderate-intensity (MOD-INT) or high-intensity (HIGH-INT) aerobic exercise training or a non-exercise control group (CON) for 24 weeks. Supervised exercise will be performed at a heart rate associated with 45–55% and 70–80% of VO2 max in the MOD-INT and HIGH-INT groups, respectively, for an exercise dose of 600 metabolic equivalents of task (MET)-minutes per week (consistent with public health recommendations). The primary outcome is change in CRF. Secondary outcomes include change in insulin sensitivity (measured via an intravenous glucose tolerance test), skeletal muscle mitochondrial oxidative capacity (via near-infrared spectroscopy), skeletal muscle measurements (i.e., citrate synthase, COX IV, GLUT-4, CPT-1, and PGC1-α), arterial stiffness (via carotid-femoral pulse wave velocity), body fat, C-reactive protein, and psychological outcomes (quality of life/exercise enjoyment). Discussion The anticipated results of the HI-PACE study will provide vital information on the health effects of high-intensity exercise in African Americans. This study will advance health disparity research and has the potential to influence future public health guidelines for physical activity. Trial registration ClinicalTrials.gov identifier: NCT02892331. Registered on September 8, 2016. Electronic supplementary material The online version of this article (10.1186/s13063-019-3611-1) contains supplementary material, which is available to authorized users.

Objective— The objectives of this study were to determine the impact of in vivo reactive oxygen species (ROS) on microvascular endothelial function in obese human subjects and the efficacy of an aerobic exercise intervention on alleviating obesity-associated dysfunctionality. Approach and Results— Young, sedentary men and women were divided into lean (body mass index 18–25; n=14), intermediate (body mass index 28–32.5; n=13), and obese (body mass index 33–40; n=15) groups. A novel microdialysis technique was utilized to detect elevated interstitial hydrogen peroxide (H 2 O 2 ) and superoxide levels in the vastus lateralis of obese compared with both lean and intermediate subjects. Nutritive blood flow was monitored in the vastus lateralis via the microdialysis-ethanol technique. A decrement in acetylcholine-stimulated blood flow revealed impaired microvascular endothelial function in the obese subjects. Perfusion of apocynin, an NADPH oxidase inhibitor, lowered (normalized) H 2 O 2 and superoxide levels, and reversed microvascular endothelial dysfunction in obese subjects. After 8 weeks of exercise, H 2 O 2 levels were decreased in the obese subjects and microvascular endothelial function in these subjects was restored to levels similar to lean subjects. Skeletal muscle protein expression of the NADPH oxidase subunits p22 phox , p47 phox , and p67 phox was increased in obese relative to lean subjects, where p22 phox and p67 phox expression was attenuated by exercise training in obese subjects. Conclusions— This study implicates NADPH oxidase as a source of excessive ROS production in skeletal muscle of obese individuals and links excessive NADPH oxidase–derived ROS to microvascular endothelial dysfunction in obesity. Furthermore, aerobic exercise training proved to be an effective strategy for alleviating these maladies.

Both Roux-en-Y gastric bypass (RYGB) surgery and exercise can improve insulin sensitivity in individuals with severe obesity. However, the impact of RYGB with or without exercise on skeletal muscle mitochondria, intramyocellular lipids, and insulin sensitivity index (SI) is unknown. We conducted a randomized exercise trial in patients (n = 101) who underwent RYGB surgery and completed either a 6-month moderate exercise (EX) or a health education control (CON) intervention. SI was determined by intravenous glucose tolerance test. Mitochondrial respiration and intramyocellular triglyceride, sphingolipid, and diacylglycerol content were measured in vastus lateralis biopsy specimens. We found that EX provided additional improvements in SI and that only EX improved cardiorespiratory fitness, mitochondrial respiration and enzyme activities, and cardiolipin profile with no change in mitochondrial content. Muscle triglycerides were reduced in type I fibers in CON, and sphingolipids decreased in both groups, with EX showing a further reduction in a number of ceramide species. In conclusion, exercise superimposed on bariatric surgery–induced weight loss enhances mitochondrial respiration, induces cardiolipin remodeling, reduces specific sphingolipids, and provides additional improvements in insulin sensitivity.

The effect of acute resistance exercise (RE) on whole body energy expenditure (EE) and α2-adrenergic receptor (α2-AR) regulation of lipolysis in subcutaneous abdominal adipose tissue (SCAAT) was determined in sedentary lean (LN) and obese (OB) men. Lipolysis was monitored using microdialysis in 10 LN [body mass index (BMI) 20.9 ± 0.6] and 10 OB (BMI 36.2 ± 2.7) men before, during, and for 24 h after RE. EE was measured before and immediately after RE for 40 min. Changes in interstitial glycerol were measured in SCAAT with three microdialysis probes perfused with a control solution, phentolamine (α2-AR antagonist), or propranolol (β-AR antagonist). EE and fat oxidation (FOX) were significantly ( P < 0.001) elevated immediately post-RE compared with pre-RE in LN and OB subjects, with no differences between groups. RE-induced increases in SCAAT glycerol concentrations from rest to peak exercise were greater in LN than in OB men in the control (LN 142.1 ± 30.8 vs. OB 65.4 ± 14.2%, P = 0.03) and phentolamine probes (LN 187.2 ± 29.6 vs. OB 66.7 ± 11.0%, P = 0.002). Perfusion of propranolol had no effect on interstitial glycerol concentrations over the time course of the experiment in either group. Plasma insulin concentrations were significantly lower ( P = 0.002) and plasma growth hormone (GH) was significantly higher ( P = 0.03) in LN compared with OB men. The mechanism behind RE contributing to improved body composition may in part be due to enhanced SCAAT lipolysis and improved EE and FOX in response to RE in LN and OB men. The blunted SCAAT lipolytic response to RE in OB compared with LN men is unrelated to RE-induced catecholamine activation of the antilipolytic α2-ARs and may be due to depressed GH in OB subjects.