Definition

By Mayo Clinic Staff

Night sweats are repeated episodes of very heavy sweating during sleep, heavy enough to soak your nightclothes or bedding. They're often caused by an underlying condition or illness.

Sometimes you may wake up after sweating heavily, particularly if you're sleeping under too many blankets or your bedroom is too warm. Although uncomfortable, these episodes aren't usually considered night sweats and aren't sign of an underlying condition or illness.

Night sweats usually happen with other concerning symptoms, such as fever, weight loss, pain in a specific area, cough or diarrhea.

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Jan. 20, 2024

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