Nag P K, Bandyopadhyay P, Ashtekar S P, Kothari D, Desai H, Nag A
National Institute of Occupational Health (Indian Council of Medical Research), Ahmedabad, India.
J Hum Ergol (Tokyo). 1996 Dec;25(2):105-13.
The working capacity of young, healthy, unacclimatized men (N = 11) was studied under long-duration (8 to 9 days) exposure to combined work and heat (dry and humid). The dry (Gr A, N = 5) and humid (Gr B, N = 6) groups were exposed to 41.3 +/- 0.6 degrees C DB, 40-50% RH and 39.2 +/- 0.6 degrees C DB, 70-80% RH, respectively, for all days of exposure. The experimental protocol was divided into: (i) direct determination of maximal oxygen uptake (VO2max) by stepped increases in bicycle ergometry everyday in the morning in the initial hours before exposure to heat, after which the recovery process of oxygen debt contraction was examined; and (ii) exposure to heat in a climatic chamber for 2 h where the subjects performed two spells of ergometric work (10 to 12 min each) at a relative intensity of 50 +/- 12 to 69 +/- 11% VO2max. The average heat exposure time for Gr A was higher (108 +/- 12 min) as compared to Gr B (95 +/- 10 min), but Gr B sustained a high heat load as reflected from the high deep-body temperature maintained during the exposure. The high body temperature load of Gr B had a significant effect on the cardiorespiratory capacity, indicating an upward trend in VO2max. This was statistically significant (p < 0.05) for the first four days of exposure. Subjects of Gr B had a relatively higher working capacity compared to those in Gr A on all days. The VO2max and analysis of the fractions of oxygen debt contraction (fast and slow component) indicated that the subjects showed a better training/heat acclimatization effect under hot, humid conditions.
对11名年轻、健康、未适应环境的男性在长时间（8至9天）的复合工作与高温（干燥和潮湿）环境下的工作能力进行了研究。干燥组（A组，n = 5）和潮湿组（B组，n = 6）在整个暴露期间分别暴露于干球温度41.3±0.6℃、相对湿度40 - 50%以及干球温度39.2±0.6℃、相对湿度70 - 80%的环境中。实验方案分为：（i）每天早晨在暴露于高温之前的初始时间段，通过逐步增加自行车测力计负荷直接测定最大摄氧量（VO2max），之后检查氧债收缩的恢复过程；（ii）在气候舱中进行2小时的高温暴露，受试者以50±12至69±11% VO2max的相对强度进行两段测力计工作（各10至12分钟）。与B组（95±10分钟）相比，A组的平均热暴露时间更长（108±12分钟），但从暴露期间维持的较高深部体温可以看出，B组承受了较高的热负荷。B组的高体温负荷对心肺功能产生了显著影响，表明VO2max呈上升趋势。在暴露的前四天，这具有统计学意义（p < 0.05）。在所有天数中，B组受试者的工作能力相对高于A组。VO2max以及对氧债收缩分数（快速和慢速成分）的分析表明，受试者在炎热潮湿条件下表现出更好的训练/热适应效果。
