Army manual of hygiene and sanitation, 1934 / [War Office].

Date:
1941
Catalogue details

Licence: Public Domain Mark

Credit: Army manual of hygiene and sanitation, 1934 / [War Office]. Source: Wellcome Collection.

    17/310 (page 19)
    For the efficient regulation of body heat when working indoors in a hot humid atmosphere it is necessary to reduce _ the temperature and humidity of the air in the room and to create a gentle air movement. _ Beneficial effects are also obtained id wearing light loose- fitting clothes. Work Part of the food taken into the body supplies energy for muscular work and in so doing gives rise to heat. The - amount of heat produced is increased if the body has to work under bad conditions such as fatigue, pain or lack of training. The trained man can convert into work 30 per cent. of the _ total energy values of the food absorbed, whereas the efficiency of the untrained man is only 20 to 25 per cent. : there is then ‘still about 70 per cent. of the available energy to account for, and this is got rid of partly in the process of living, partly as waste products, but chiefly as heat. If this heat were not removed, the body would become overheated and damaged during severe muscular work. In addition to providing fresh oxygen and removing carbon dioxide, the blood in its circula- _tion carries away the excess heat which is then got rid of in the air expired from the lungs, by the evaporation of sweat _and by the urine. The effect of muscular work is :— Lt. Slight heating up of the body, which, as in the case of any other engine, works better when warmed up. The normal temperature of the body is between 97° and 99° F., but during work it is 100-5° F 2. Increased rapidity of breathing to bring more oxygen to the lungs. 3. Increased rapidity of circulation of the blood to bring more oxygen to the muscles and to carry away heat and waste products. 4, Increased production of sweat to assist evaporation from the skin. _ Inability on the part of the body to compete with work becomes apparent by excessive sweating, distress and fatigue, ‘and these set in earlier in the untrained man than in the man whose muscles are trained to perform muscular work. oe Rest | - Rest is necessary to allow the muscles to recover from “work and to refit themselves for further efforts. Rest is also Necessary for the repair and replacement of worn parts of the remainder of the body such as the brain and digestive organs. ™ 19