The effects of oral inosine (a hypoxanthine riboside) supplementation on aerobic capacity were studied in fourteen healthy male physical education students, 20-23 years of age. A double-blind, inosine-placebo, crossover study was used. The subjects were equally divided into two groups

A and B. Group A received inosine for the first six weeks then placebo for ancther six weeks whikl group B underwent the reversed regimen. Each subject undertook inosing (200 mo) or placebo lactcse (250 mo) each time, 3 times/ady after meal for everyday throuahout the twelve weeks period. Tests of maximal exygen consumption (VO2max) and endurance exercise performance were performed in deach supjeect on two separate days in prior to adminitration of the food supplements. The tests were repeated at the end of every three week of the twelve-week experiment. The VO2max was indirectly determined in each subject with a bicycla craometer and the Astrand heart rate-O2 consumption Nomogram. Prologned submaximal exercise was performed on the bicycle ergometer at a constant speed of 60 rpm and the work intensity of 60% of individuals maximum heart rate for 30 minutes. Venous blood samples (8 ml each) were collected prior to and at the last minute of prolonged exercise in order to assess hemoglobin conentration (Hb), hematocrit (Hct), 2,3-DPG, plasma glucose and serum uric acid. It was found that there was no significant benificial effect of oral inosine administration on both the Vo2max and the prolonged exercise performance and also on the other performance dependent variables. In stead, serum and urinary uric acid concentrations were significantly increased during the oral inosine trial. These findings indicate that inosine supplementation at the given regimen exerted no significant benificial ergogenic influence on areobic physical performance while its adversed cause of accumulation of uric acid in the body occurred.