Heat exhaustion

When we get hot, perspiration forms and evaporates. This pulls heat out of the body and maintains normal body temperature, The sweat also carries fair amounts of salts with it which are important for the body. A deficiency of these salts causes weakness and sometimes severe cramps.
Heat exhaustion occurs when someone has perspired heavily after long exertion or on a very hot day. The body will then lose an excessive amount of water and salts. In this condition body temperature will normally rise only slightly. The person feels faint, exhausted, and sometimes nauseated. The skin is moist and looks pale. The pulse becomes fast and feeble. Cramps may develop.

Treatment:

Get the person into a cool place and have him or her lie down. Loosen any tight clothing and raise the feet. Slightly salty drinks such as twig tea with soy sauce or water boiled with salted plums (umeboshi), are very good. Recovery should be soon.