Abstract des Autors

The purpose of the present investigation was to assess the influence of physical activity on serum leptin levels. 25 leisure time athletes participated in a 3-months training program. Subjects exercised three to four days per week for 45 minutes/day and a maximal training volume of 30 km/week. The intensity of exercise was determined by lactic acid levels, the subjects exercised between 2-3 mmol/l lactic acid. The aerobic capacity (4 mmol lactic acid threshold) increased significantly from 3,08+/-0,64 to 3,33+/-0,61 m/s (p=0,000) after the training period. Serum leptin levels rose significantly from 4,95+/-4,7 to 6,33+/-6,18 ng/ml (p=0,004), whereas the Body Mass Index remained unchanged. Serum leptin was measured by RIA (Fa. Mediagnost Tuebingen). The increased energy turnover at a well adjusted energy balance seems to elevate serum leptin. 13 leisure time athletes completed an acute bout of exercise with a 2,5 hours extensive run. Serum leptin, creatinine and free fatty acids were determined before, immediately after the run, and during the recovery period, 1h, 2h, 6h and 24h after the run. Serum leptin decreased significantly from 1,36+/-1,06 to 0,93+/-0,74 ng/ml (p=0,002) and 24h after the run the leptin levels were still significantly lower (1,05+/-1,14 ng/ml) than the pre-race values. The decreased serum leptin after strenuous exercise are in agreement with previous basic research studies, for the leptin production in the adipocyte is suppressed by catecholamines and free fatty acids, as they can be observed under this kind of exercise. Leptin, the "sensor of energy balance" seems to be closely related to energy metabolism and is influenced by volume and intensity of training. Verf.-Referat