Factors that increase the risk of hyperthermia may include:

* Dehydration.

* High blood pressure or other health conditions that require changes in diet. For example, people on salt-restricted diets may be at increased risk. However, salt pills should not be used without first consulting a doctor.

* Heart, lung and kidney diseases, as well as any illness that causes general weakness or fever.

* Use of multiple medications. It is important, however, to continue to take prescribed medication and discuss possible problems with a physician.

* Reduced sweating, caused by medications such as diuretics, sedatives, tranquilizers and certain heart and blood pressure drugs.

* Age-related changes to the skin such as poor blood circulation and inefficient sweat glands.

* Being substantially overweight or underweight.

* Alcohol use.