title: Assessment of plasma opioid peptides, beta-endorphin and met-enkephalin, at the end of an international nordic ski race.
abstract: Plasma met-enkephalin, beta-endorphin, cortisol and lactic acid concentrations were measured in seventeen volunteer male subjects at rest and after a long-distance nordic ski race. Immediately after the race, mean plasma met-enkephalin did not show any significant change, but significant rises in beta-endorphin, cortisol and lactic acid were noted in all skiers. The change in beta-endorphin with exercise was significantly related to the change in cortisol (r = 0.68; p less than 0.001) and to the change in plasma lactic acid (r = 0.60; p less than 0.001). Furthermore, the experienced skiers training over 150 km X week-1 of nordic ski had significantly faster skiing times in this event and showed greater beta-endorphin, cortisol and lactic acid levels than the recreational skiers who trained for 20 km X week-1. Our results imply that the changes in plasma beta-endorphin depend on the intensity of exercise. However the significance of higher levels of skiing training or previous nordic ski experience in the release of beta-endorphin is expected and cannot be excluded.
mesh_terms: D000328:Adult; D004723:Endorphins / Q000097:blood*; D004744:Enkephalin, Methionine / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010806:Physical Education and Training; D012865:Skiing; D013997:Time Factors; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D007773:Lactates; D019344:Lactic Acid; D004744:Enkephalin, Methionine; D001615:beta-Endorphin; D006854:Hydrocortisone