Leptin responses to long-term cardiorespiratory exercise training without concomitant weight loss: a prospective study

Aim. The aims of the present study were to examine 1) whether changes in circulating leptin levels occur in response to six months of aerobic exercise training (ET) without concomitant weight loss; 2) whether there is a different response with respect to gender; and 3) the relationship between age and leptin and whether this relationship has any impact on the response to ET without weight-loss. Methods. Thirty-eight healthy, sedentary men and women (age 38.43 +/- 2.24, range 18-59 years) participated in 6 months of supervised, moderate intensity (ET) performed 4 days per week. Maintenance of usual dietary practices were encouraged to minimize weight-loss. Participants were evaluated for circulating fasting leptin, body mass, body fat percentage and maximal aerobic power (V(over dot)O-2max,) prior to and after ET. Results. There was no decrease in body weight or leptin concentration (17.69 +/- 2.67 vs 16.85 +/- 3.12 ng dL(-1)). Gender did not affect the response to exercise training. The bivariate correlation between leptin and age was not significant, but the relationship reached significance after controlling for body fat percentage and V(over dot)O-2max (r=-0.358, P < 0.05). Age did not affect the response of leptin concentration to ET. Conclusion. It is probable that changes in leptin concentration reported previously with ET may be attributable to concomitant weight loss, bull age does not play a role in how leptin responds to ET.