The diseases caused by The Heat stroke is the most dangerous health effect of working in hot environments, The Heat exhaustion while it is serious is less severe than heat stroke and primarily due to lack of adequate water intake (fluid replacement), The Heat syncope or fainting is the mildest form and is caused also by inadequate fluid intake. First aid is usually sufficient, The Heat cramps is the result of doing heavy work in hot environment and is due to electrolyte (salt) imbalance caused by excessive sweating.