Jirák Z, Jokl M V, Jiráková H, Bajgar P
Institute of Hygiene, Ostrava, Czech Republic.
Physiol Res. 1997;46(4):307-17.
A group of four efficient mine rescuers 25 to 35 years old were exposed to a load of a cyclo-ergometer (stages A and B) and a hand ergometer (stage E) in a climate chamber. The total 120 min period of work was divided into four work intervals, 30 min each. There were 5-min breaks between the individual intervals. The load on the ergometer was selected in the range of 25 to 150 W, Tg=20 to 40 degrees C, rh=40 to 80% and v(a)=0.2 to 1.5 m x s(-1). The thermal resistance of the working suit was 0.65 clo at stage A, 1.07 clo at stage B and 0.81 clo at stage E. A total of 200 experiments with 50 combinations of the work and climate loads were made. The heart rate, oxygen consumption, carbon dioxide production, body temperature, skin temperature, water loss by sweating and perspiration, dry and wet bulb air temperature, air velocity and globe temperature were measured during the experiments. The expected production of sweat (SR) and the amount of accumulated heat in the body (Qmax) were calculated for each combination of the work-climate conditions by a computing program ISO 7933:1989 as well as by our own program. Good agreement was reached between the measured and predicted SR values, calculated by the ISO program (r=0.871) as well as between the values calculated by the two programs, respectively (r=0.985). The experimental results have shown good agreement between the predicted and actually measured values of temperature of the body core as an index of short-term tolerable climate load. The values of short-term tolerable time of work calculated at the level of accumulated heat in the body of 50 W x h x m(-2) resulted in an increase of body core temperature by 0.8 to 1.0 K. The values of heart rate did not mostly exceed 140 beats/min, reaching in exceptional (three) cases values above 150 beats/min. The authors recommend to limit the long-term work-heat (climatic) load during a higher metabolic rate (M >80 W x m(-2) including the basal metabolic rate) of acclimatized males and females at a sweat rate SR=270 g x h(-1) x m(-2), of non-acclimatized persons at SR=206 g x h(-1) x m(-2). The limit for low metabolic rates (M < or = 80 W x m(-2)) for non-acclimatized and acclimatized persons is proposed for long-term tolerable loads of SR=147 g x h(-1) x m(-2). The short-term tolerable load by heat storage within the organism for all categories is proposed as Qmax=50 W x h x m(-2).
一组年龄在25至35岁之间的四名高效矿山救援人员在气候舱内承受了蹬车测力计（A和B阶段）和手摇测力计（E阶段）的负荷。总共120分钟的工作时间分为四个工作时段，每个时段30分钟。各时段之间有5分钟的休息时间。测力计的负荷选择范围为25至150瓦，Tg = 20至40摄氏度，rh = 40至80%，v(a) = 0.2至1.5米×秒（-1）。工作防护服的热阻在A阶段为0.65克罗，B阶段为1.07克罗，E阶段为0.81克罗。针对50种工作和气候负荷组合共进行了200次实验。在实验过程中测量了心率、耗氧量、二氧化碳产生量、体温、皮肤温度、出汗和排汗导致的水分流失、干湿球气温、风速和球温度。通过计算程序ISO 7933:1989以及我们自己的程序，针对每种工作 - 气候条件组合计算了预期出汗量（SR）和体内累积热量（Qmax）。由ISO程序计算得出的测量SR值与预测值之间（r = 0.871）以及两个程序分别计算得出的值之间（r = 0.985）达成了良好的一致性。实验结果表明，作为短期可耐受气候负荷指标的体核温度预测值与实际测量值之间具有良好的一致性。在体内累积热量为50瓦·时·米（-2）的水平下计算得出的短期可耐受工作时间值导致体核温度升高0.8至1.0开尔文。心率值大多未超过140次/分钟，在特殊（三次）情况下达到150次/分钟以上。作者建议，对于适应环境的男性和女性，在出汗率SR = 270克·时（-1）·米（-2）的较高代谢率（M > 80瓦·米（-2），包括基础代谢率）期间，以及对于未适应环境的人员在SR = 206克·时（-1）·米（-2）时，限制长期工作 - 热（气候）负荷。对于未适应环境和适应环境的人员，在低代谢率（M ≤ 80瓦·米（-2））情况下，长期可耐受负荷的出汗率建议为SR = 147克·时（-1）·米（-2）。对于所有类别，通过生物体内部蓄热得出的短期可耐受负荷建议为Qmax = 50瓦·时·米（-2）。
