Sleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating (hyperhidrosis) during sleep. The sufferer may or may not also suffer from excessive perspiration whilst awake.

Night sweats may occur for genetic reasons and may be relatively harmless. However, they can be distressing and disrupt sleep patterns if severe; the patient may be frequently awakened due to the discomfort of damp sleepwear.

Sleep hyperhidrosis may occur at any age, but is most commonly seen in early adulthood.

The condition may be considered a sign of various disease states, including:

• Brucellosis
• Cerebral palsy
• Cerebral and brain stem strokes
• Chronic pneumonia
• Epilepsy
• Familial dysautonomia
• Head injury
• HIV
• Hodgkin's disease
• Hypothalamic lesions
• Pulmonary histoplasmosis
• Subacute endocarditis
• Tuberculosis