Gesundheitszentrum St. Gallen, St. Gallen, Switzerland.
Res Sports Med. 2011 Jan;19(1):14-27. doi: 10.1080/15438627.2010.510039.
We investigated the change in body composition and hydration status in 27 male ultra-runners during a 100 km ultra-run. The athletes drank fluids ad libitum during the run; intake of calories, fluids, and electrolytes during performance were determined. Body mass decreased by 1.9 kg, haematocrit decreased, plasma [Na(+)] remained unchanged, and urinary specific gravity and plasma volume increased. Fluid intake was 0.52 (0.18) L/h and was related to running speed (r = 0.50; p = 0.0081). Δ body mass was associated with total fluid intake during the race (r = 0.49, p = 0.0095). Sodium intake amounted to 425 (478) mg/h and potassium intake to 140 (179) mg/h. Sodium and potassium intake were not related to either postrace concentration or change in plasma concentration. Sodium intake, however, was related to Δ urinary sodium concentration (r = 0.45, p = 0.0227). The increase in plasma volume was significantly and negatively related to both postrace plasma [Na(+)] (r = - 0.42, p = 0.0278) and the postrace potassium-to-sodium ratio in urine (r = - 0.44, p = 0.0218). To conclude, we found no fluid overload in these ultra-runners, the increase in plasma volume was most probably due to a stimulation of the renin-angiotensin-aldosterone system (RAAS) since sodium intake was not related to both the change in plasma [Na(+)] or postrace plasma [Na(+)].
我们研究了 27 名男性超长距离跑步运动员在 100 公里超长距离跑步过程中身体成分和水合状态的变化。运动员在跑步过程中自由饮水；记录比赛期间的热量、液体和电解质摄入情况。运动员体重减轻 1.9 公斤，红细胞压积下降，血浆 [Na(+)] 保持不变，尿比重和血浆容量增加。液体摄入量为 0.52（0.18）L/h，与跑步速度相关（r = 0.50；p = 0.0081）。Δ 体重与比赛期间的总液体摄入量相关（r = 0.49，p = 0.0095）。钠摄入量为 425（478）mg/h，钾摄入量为 140（179）mg/h。钠和钾的摄入量与赛后浓度或血浆浓度变化均无关。然而，钠摄入量与 Δ 尿钠浓度相关（r = 0.45，p = 0.0227）。血浆体积的增加与赛后血浆 [Na(+)]（r = - 0.42，p = 0.0278）和赛后尿中钾钠比（r = - 0.44，p = 0.0218）均呈显著负相关。综上所述，我们在这些超长距离跑运动员中未发现液体过载现象，血浆体积的增加很可能是由于肾素-血管紧张素-醛固酮系统（RAAS）的刺激所致，因为钠摄入量与血浆 [Na(+)]的变化或赛后血浆 [Na(+)]均无关。
