Some causes of excessive perspiration include strenuous physical activity, fever and warm temperatures, according to Mayo Clinic. Some medical conditions cause excessive sweating, including diabetes, hyperthyroidism, menopause and tuberculosis. Endocarditis, generalized anxiety disorder, heart attack and HIV/AIDS also cause excessive perspiration.
In general, excessive perspiration related to a disease or medical condition or as a side effect of a drug occurs when it affects a large portion of the body and occurs during both periods of sleep and while a person is awake, advises Mayo Clinic. An underlying medical problem does not cause focal hyperhidrosis, which is sweating that occurs during the daytime for no apparent reason, causing perspiration in the armpits, on the soles of the feet and on the palms of the hands.