Caffeine vs caffeine-free sports drinks: effects on urine production at rest and during prolonged exercise.

摘要: We compared the effects of caffeinated vs non-caffeinated carbohydrate electrolyte (CE) drinks on urine volume (UV), free water clearance (CH2O), fractional excretion (FEH2O), and osmolar during 4 h rest or 1 followed by 3 cycling at 60% VO2max in six subjects. also tested maximal performance 85% following 3-h exercise trials. Throughout two resting trials + trials, subjects ingested CE (total = 35 ml/kg) without (PLAC) with (CAFF) caffeine (25 mg/dl). Blood samples were collected, body weight UV recorded every hour. Urine blood analyzed for osmolality creatinine, plasma catecholamine concentrations determined. At rest, mean (+/-SE) between 60 min 240 was greater CAFF (1843 +/- 166 ml) PLAC (1411 181 (p < 0.01); difference (398 32 (490 57 not significant. Cycling unaffected caffeine. Plasma different but than 0.01) may have counteracted diuretic effect observed rest. Thus, consumed moderate endurance apparently does compromise bodily hydration status.