BASAL CONCENTRATIONS OF ANABOLIC AND CATABOLIC HORMONES IN RELATION TO ENDURANCE EXERCISE AFTER SHORT-TERM CHANGES IN DIET

This study aimed to use a classical model to analyse whether alteratio ns in performance due to short-term changes in diet are reflected in p eripheral basal anabolic and catabolic hormone concentrations. Six hea lthy students (two women and four men) performed a cross-over study in cluding three test situations. The reference test was preceded by each subject's normal unrestricted diet of western type (N). After this, t hree of the subject's were provided a carbohydrate-rich diet (CHO) for 3 days followed by the second test. Following this test, a carbohydra te deficient, protein/fat rich diet (F) was provided for another 3 day s followed by the third test. The remaining three subjects had these d iets in reverse order. Basal concentrations of cortisol (C), sex hormo ne-binding globulin (SHBG), insulin-like growth factor (IGF-I), total- testosterone and non-SHBG-bound-testosterone (NST), the NST: C ratio a nd an ergometer cycle endurance test with measurements of submaximal a s well as measurements of maximal oxygen uptake, heart rate, respirato ry exchange ratio (R), free fatty acids (FFA), glycerol and lactate we re investigated. All the subjects were involved in athletics for recre ation and during the study they performed daily physical exercise acco rding to their normal routine. After the F diet only two of the subjec ts completed the test. One woman dropped out after 16 min, two men dro pped out after 14 min and one after 13 min of cycling. After the CHO d iet all six subjects completed the ergometer cycle test. Considering t he whole group, there were no significant differences in lactate or gl ycerol concentrations during the study. The FFA concentrations were si gnificantly higher after consuming the F diet compared to the CHO diet ; and correspondingly R was significantly increased after consuming th e CHO diet compared to the F diet. These changes in physiological char acteristics due to short-term dietary changes were not reflected in co ncomitant alterations in the concentrations of anabolic or catabolic h ormones, or SHBG.