Biochemical changes in blood during the long and short triathlon competition.

The purpose of the study was to compare the effects of long (3.8 km swimming, 180 km biking, 42.2 km running, n = 7) and short (1.5 km swimming, 42 km biking, 14 km running, n = 14) triathlons on blood hormones, metabolites and substrates. Both variants of triathlon caused a significant rise in cortisol, somatotropin and aldosterone levels, the insulin and C-peptide levels decreased. The progesterone level increased considerably only after long triathlon. The testosterone level did not change essentially. The level of plasma glucose, total cholesterol, HDL, LDL did not change substantially during the both competitions. FFA concentration increased significantly and triglycerides concentration decreased only during the prolonged variant.