Cardio- and neurometabolic effects of lower-body pressure-supported exercise in obese non-diabetic women: Resetting autonomic imbalance?

Abstract

AbstractBackground:Overnutrition and underactivity cause most chronic disease via inflammation and stress. Life-style changes such as diet is largely unsuccessful and exercise is painful, uncomfortable and difficult for people with diabesity, cardiorespiratory and joint diseases and cognitive decline affecting their ability to ambulate and adhere to exercise guidelines. Diets or exercise causing weight loss are stressful and trigger numerous redundant counter regulatory mechanisms defending lean body mass, explaining failures to sustain these behaviors. In this hypothesis-generating pilot study we used a NASA-developed weight supporting lower-body positive pressure (LBPP) treadmill providing comfortable low-amount, low intensity walking, challenging current exercise guidelines.Methods:Sixteen nondiabetic, untrained, Black volunteer women (BMI 28-50), age 18-56 years were studied by anthropometry, analyses of energy expenditure and blood chemistry: oral glucose tolerance tests (OGTT) with insulin, C-peptide, GLP-1 and FFA and fasting lipids, cytokines, adipokines and appetitive peptides, before and after 10 weeks of twice weekly 30-minute weight supported LBPP treadmill sessions.Results:We found novel baseline associations between gluco- and neuro-regulatory peptides and plasma lipids, inflammatory cytokines and appetitive hormones related to neurogenesis, mood and energy balance. Post-study, independent of body weight or energy expended there were significant decreases in OGTT plasma insulin (p=0.002) and GLP-1 (p=0.060) and fasting triglycerides (p=0.029), ghrelin (p=0.008) and changes in most molecules including increased leptin and beta-endorphin. Correlations between changes among different classes of peptides were highly significant, notably leptin - adiponectin, and beta-endorphin - oxytocin and orexin A. We propose synergy between low-amount, low-intensity exercise at levels below thresholds of increased sympathetic tone, and baro-physiological effects of LBPP normalizing parasympathetic tone.Conclusion:Brief, low-dose, lower-body positive-pressure weight-supported treadmill exercise improved cardiometabolic fitness and exhibited favorable changes in neuro-regulatory peptides without weight loss in inner-city obese Black women.