Basal concentrations of anabolic and catabolic hormones in relation to endurance exercise after short-term changes in...

This study aimed to use a classical model to analyse whether alterations in performance due to short-term changes in diet are reflected in peripheral basal anabolic and catabolic hormone concentrations. Six healthy students (two women and four men) performed a cross-over study including three test situations. The reference test was preceded by each subject's normal unrestricted diet of western type (N). After this, three of the subject's were provided a carbohydrate-rich diet (CHO) for 3 days followed by the second test. Following this test, a carbohydrate deficient, protein/fat rich diet (F) was provided for another 3 days followed by the third test. The remaining three subjects had these diets in reverse order. Basal concentrations of cortisol (C), sex hormone-binding globulin (SHBG), insulin-like growth factor (IGF-I), total-testosterone and non-SHBG-bound-testosterone (NST), the NST:C ratio and an ergometer cycle endurance test with measurements of submaximal as well as measurements of maximal oxygen uptake, heart rate, respiratory exchange ratio (R), free fatty acids (FFA), glycerol and lactate were investigated. All the subjects were involved in athletics for recreation and during the study they performed daily physical exercise according to their normal routine. After the F diet only two of the subjects completed the test. One woman dropped out after 16 min, two men dropped out after 14 min and one after 13 min of cycling. After the CHO diet all six subjects completed the ergometer cycle test. Considering the whole group, there were no significant differences in lactate or glycerol concentrations during the study.(ABSTRACT TRUNCATED AT 250 WORDS)