Leptin responses to short term exercise in college level male rowers.

OBJECTIVE To investigate plasma leptin response to short term exercise in college level male rowers. METHODS Thirteen rowers performed a 30 minute maximal rowing ergometer test. Venous blood samples were obtained before, immediately after, and after 30 minutes of recovery. Concentrations of leptin, insulin, growth hormone, insulin-like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) were measured. RESULTS Plasma leptin was significantly (p<0.05) decreased (from a mean (SD) of 2.7 (0.6) to 2.1 (0.8) ng/ml) and growth hormone significantly increased (from 0.6 (0.9) to 4.6 (5.4) microIU/l) immediately after the 30 minute maximal rowing exercise session (distance covered 7870.4 (443.3) m; blood lactate immediately after the test 14.9 (4.3) mmol/l). All other blood variables measured were not significantly changed as a result of the ergometer test. A positive relation was observed between the decreased plasma leptin concentration immediately after the test and the distance covered (R(2) = 0.645; p<0.05). Changes in leptin and IGF-I concentrations immediately after the test were also related (R(2) = 0.390; p<0.05). Percentage body fat explained 89.6% (p<0.05) of the variance (R(2) x 100) in basal leptin concentration. After normalisation for body fat, basal leptin was related (p<0.05) to basal insulin (r = 0.82) and training history (r = -0.60). CONCLUSION Leptin is sensitive to relatively short term intense exercise when all major muscles are involved.