The acute effects of intermittent treadmill running on hunger and plasma acylated ghrelin concentration in individuals with obesity

Body weight is regulated by both food intake and energy expenditure. Ghrelin, a hormone produced by the stomach and pancreas, enhances appetite. This study was undertaken to determine the effects of intermittent treadmill running on acylated ghrelin and appetite in individuals with obesity. Nine inactive male students, with a mean age of 20.56±0.48 yrs, a body mass index of 32.68±0.84 kg/m2 and a maximum oxygen uptake of 34.21±1.48 ml/kg/min, participated in the study in two trials (control and exercise) in a counterbalanced, randomized design. The protocol included intermittent running with a constant intensity at 65% of VO2 max on a treadmill. Blood samples were collected before, during, and 2h after cessation of the exercise. Acylated ghrelin concentrations and hunger ratings decreased significantly in the second phase and remained lower than baseline (P=0.006 and P=0.002, respectively) at the end of the exercise. The total area under the curve values and hunger ratings (all P<0.0005) were significantly lower in the exercise trial compared with the control state. Similarly, growth hormone rose significantly at the second phase and remained higher than baseline (P=0.033) at the end of the exercise trial. These findings indicate that acylated ghrelin and appetite are reduced by running at 65% of VO2 max and remain lower than baseline even two hours afterwards in individuals with obesity. Growth hormone seems to be more responsible for this suppression. Further studies are required to investigate whether this protocol could elicit the same effects in short-term training programs.