Purine loss after repeated sprint bouts in humans

The influence of the number of sprint bouts on purine loss was examined in nine men (age 24.8 +/- 1.6 yr, weight 76 +/- 3.9 kg, peak O-2 consumption 3 .87 +/- 0.16 l/min) who performed either one (B1), four (B4), or eight (B8) 10-s sprints on a cycle ergometer, 1 wk apart, in a randomized order. Fore arm venous plasma inosine, hypoxanthine (Hx), and uric acid concentrations were measured at rest and during 120 min of recovery. Urinary inosine, Hx, and uric acid excretion were also measured before and 24 h after exercise. During the first 120 min of recovery, plasma inosine and Hx concentrations, and urinary Hx excretion rate, were progressively higher (P < 0.05) with a n increasing number of sprint bouts. Plasma uric acid concentration was hig her (P < 0.05) in B8 compared with B1 and B4 after 45, 60, and 120 min of r ecovery. Total urinary excretion of purines (inosine + Hx + uric acid) was higher (P < 0.05) at 2 h of recovery after B8 (537 +/- 59 mu mol) compared with the other trials (B1: 270 + 76; B4: 327 + 59 pmol). These results indi cate that the loss of purine from the body was enhanced by increasing the n umber of intermittent 10-s sprint bouts.