Kotze H F, van der Walt W H, Rogers G G, Strydom N B
J Appl Physiol Respir Environ Exerc Physiol. 1977 May;42(5):711-6. doi: 10.1152/jappl.1977.42.5.711.
Thirteen male volunteers were heat acclimatized for 4 h/day for 10 consecutive days. Three to four hours before each heat exposure, four of the subjects received an oral dose of 250 ascorbic acid, five received 500 mg ascorbic acid, and the remaining four a placebo. Rectal temperature, heart rate, and sweat rate were measured hourly during exposure. Venous blood samples were collected before each administration of drug or placebo. On days 1, 2, 3, 5, 8, and 10, blood samples were also collected just prior to heat exposure and after two and four hours of exposure. In the subjects receiving ascorbic acid, total circulating plasma ascorbic acid increased over the first three or four days to a plateau level some fourfold higher than in the subjects receiving the placebo. The plateau level was the same in the subjects receiving 250 mg and 500 mg ascorbic acid. The increased ascorbic acid concentration was shown to be associated with a reduction in total sweat output, independent of rectal temperature, and a reduction in rectal temperature, independent of total sweat output. The results indicate that ascorbic acid may be effective in reducing heat strain in unacclimatized individuals.
13名男性志愿者连续10天每天进行4小时的热适应训练。在每次热暴露前3至4小时，4名受试者口服250毫克抗坏血酸，5名受试者口服500毫克抗坏血酸，其余4名受试者服用安慰剂。在暴露期间每小时测量直肠温度、心率和出汗率。在每次给药或服用安慰剂前采集静脉血样。在第1、2、3、5、8和10天，还在热暴露前以及暴露2小时和4小时后采集血样。在服用抗坏血酸的受试者中，总循环血浆抗坏血酸在前三天或四天内增加至稳定水平，比服用安慰剂的受试者高出约四倍。服用250毫克和500毫克抗坏血酸的受试者的稳定水平相同。结果表明，抗坏血酸浓度的增加与总出汗量的减少（与直肠温度无关）以及直肠温度的降低（与总出汗量无关）有关。结果表明，抗坏血酸可能对减轻未适应环境个体的热应激有效。
