|Other names||Sleep sweats, nocturnal hyperhidrosis|
|Specialty||Infectious disease, oncology|
Night sweats, or also referred to as nocturnal hyperhidrosis (Hyperhidrosis - a medical term for excessive sweating  + nocturnal - night) is the repeated occurrence of excessive sweating during sleep. The person may or may not also perspire excessively while awake.
One of the most common causes of night sweats in women over 40 is the hormonal changes related to menopause and perimenopause. This is a very common occurrence during the menopausal transition years. Over 80% of women experience hot flashes, which may include excessive sweating, during menopause. 
Night sweats range from being relatively harmless to a sign of underlying disease. Night sweats may happen because the sleep environment is too warm, either because the bedroom is unusually hot or because there are too many covers on the bed. Night sweats have been associated with a long list of clinical conditions. However, there is very little evidence that supports clinical recommendations for this condition.
- Endocrine disorders
- Rheumatic disorders
- Autonomic over-activity
- Inflammatory bowel disease (IBD) - Crohn's disease/ulcerative colitis
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