Influence of Aerobic Exercise on Appetite-Regulating Hormones, Ghrelin-o-Acyltransferase and Perceived Hunger in Normal Weight and Obese Adults

Background: Obesity is a major public health issue in the United States (U.S.), affecting an estimated 78 million US adults. Aerobic exercise (AE) is recommended by the American College of Sports Medicine to prevent and treat obesity, yet the effects of AE on circulating hunger hormones including acylated ghrelin and its biological catalyst, ghrelin o-acyltransferase (GOAT) are less known. Objectives: We investigated the effects of AE on circulating concentrations of appetite regulating hormones and GOAT in a pilot sample of adults classified with normal weight (NW) and obese (OB) body weight status. Methods: Using a quasi-experimental design, nine adults with NW (n=4, body mass index [BMI] = 21.3±1.2 kg/m2) and OB (n=5, BMI = 38.9±6.2 kg/m2) body weight status completed a preliminary health/fitness assessment. Participants returned to the laboratory on three separate occasions, separated by ≥ 48 hours to perform cycle exercise at 30% and 60% oxygen uptake reserve (VO2R) or a seated control session with no exercise for 40 min. Fifteen mL of blood was taken pre-and-post exercise and control and were assayed in duplicate. Nonparametric procedures determined whether mean rank differences existed between NW and OB for acylated ghrelin, leptin, insulin, and GOAT in response to exercise and control. Alpha levels were set a priori to p 0.05. Results: Significant mean rank reductions were found in GOAT after compared to before AE and control for NW and OB (p.05). Significant mean rank differences were found in acylated ghrelin after compared to before performing AE at 60% VO2R in NW and OB (p.05); however, differences were not observed between NW and OB (p.05). Conclusions: Our findings reveal the first available data regarding the effects of AE on GOAT, with NW and OB experiencing equivocal changes pre-to-post AE at 60% VO2R, and in response to a seated control session.