RESUMO
BACKGROUND:No studies currently focus on the measurement of daily water loss under certain physical activity level continuously and precisely. OBJECTIVE:To provide evidence for daily water requirement in Chinese young men based on the measurement of the daily water loss in Chinese young men under moderate physical activity. METHODS:Twenty male subjects were enroled, and 23-hour whole-body sweat loss and urine output were measured using high-precision body weighting scale in whole-room indirect calorimeter. The results were converted to daily (24-hour) water requirement to determine the daily water requirement. Daily whole-body sweat loss per unit body weight, daily whole-body sweat loss per unit fat free mass and daily whole-body sweat loss per unit surface area were calculated. RESULTS AND CONCLUSION:In Chinese young men, daily water loss was (3 339.7±509.9) g, daily urine output was (1 982.9±449.5) g and daily whole-body sweat loss was (1 356.7±215.6) g. There was a linear correlation between water intake and water loss (r=0.616,P < 0.05). Daily whole-body sweat loss per unit body weight was (21.0±3.6) g/kg, daily whole-body sweat loss per unit fat free mass was (25.8±3.9) g/kg and daily whole-body sweat loss per unit surface area was (799.4±129.4) g/m2. Daily water requirement of Chinese young men under moderate physical activity is approximately 3 340g, and moreover, water loss increases with the increase of water intake.
