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- Night sweats can be caused by hormonal fluctuations or disorders, infection, fever, and more.
- Many women will experience night sweats during menopause or perimenopause.
- Occasional night sweats aren't a cause for concern, but see a doctor if they are persistent.
- Visit Insider's Health Reference library for more advice.
Ever wake up in the middle of the night dripping in sweat, like you just ran a marathon? Then you're one of many people who have experienced night sweats, or sleep hyperhidrosis.
Night sweats aren't related to your environment, like if your room is too hot. Rather, they're usually caused by hormonal fluctuations in the body or are a side effect of medication.
Either way, they can have a big impact on your sleep. Night sweats often wake you up, and you may have to change your clothes or sheets in order to comfortably fall back asleep.
Here's what you need to know about the common causes of night sweats and when to see a doctor.
1. Menopause
Night sweats are often linked to the hormonal fluctuations during menopause and perimenopause.
More than 80% of women in perimenopause and menopause experience hot flashes - or sudden, intense feelings of warmth. When these happen at night, they can cause night sweats.
Menopause occurs 12 months after a woman has her last menstrual period, usually between the ages of 45 and 55. Perimenopause occurs in the 7 to 14 years before menopause.
Specifically, the drop in the hormone estrogen, which occurs during perimenopause, is linked to night sweats because it affects the body's temperature regulation.
"Women experience more night sweats related to hormonal changes during perimenopause and menopause," says Soma Mandal, MD, board-certified internist at Summit Medical Group, in Berkeley Heights, New Jersey.
Night sweats during menopause aren't cause for concern, but they can be uncomfortable.
If you're experiencing night sweats during menopause, talk to your doctors about treating the symptoms with medications that help replace estrogen.
2. Hormonal disorders
Hormonal disorders can make it difficult for your body to regulate its normal temperature, which can cause night sweats.
Body temperature is regulated by the hypothalamus, an area in the brain that produces hormones. When your hormones are out of balance, it sometimes means that the hypothalamus isn't able to regulate temperature correctly.
Hormonal disorders that can affect body temperature and cause night sweats include:
- Hyperthyroidism. This condition leads to overproduction of the thyroid hormone, which causes increased sweating, including night sweats.
- Pheochromocytoma. This is a tumor on the adrenal gland which makes it produce too many hormones. Symptoms can include night sweats and elevated heart rate.
- Carcinoid syndrome. This is a rare disease linked to tumors in the endocrine system. In some cases, it can lead to excess production of the neurotransmitter serotonin. One of the symptoms is excess sweating.
If you experience other symptoms of a hormonal imbalance, such as weight changes or headaches, talk with your doctor about these symptoms.
3. Infection
If you're sick with a viral or bacterial infection, your body raises its internal temperature to fight off the infection, which is what causes fever.
This increase in body temperature can lead to sweating - and night sweats are a common symptom associated with fevers.
"Various infections such as HIV, tuberculosis, and infectious mononucleosis can cause night sweats," Mandal says. "These conditions can produce chemicals called cytokines which combat infection. Cytokines can induce fever and night sweats."
If you experience a fever in addition to night sweats, you may want to check in with your doctor about what type of infection you have.
4. Medications
Certain medications can cause night sweats, including antidepressants for depression or anxiety.
A 2018 study found that up to 14% of people on Selective Serotonin Reuptake Inhibitors (SSRIs) - the most common form of antidepressants - experience excessive sweating and night sweats.
The study authors concluded that these medications likely affect the areas of the brain that produce hormones, which help control temperature and sweating.
Other medications that may cause night sweats include:
- Triptan migraine medications, like Relpax or Frova
- Hormone-blocking medications, like Arimidex or Femara
- Diabetes medications, like Metformin or insulin (if you're taking these, check your blood sugar to ensure that it isn't too low and causing the night sweats)
If your medications are causing night sweats, you can try sleeping in lighter clothes or keeping the room cooler. If night sweats continue to interrupt your sleep, you should talk to your doctor about your concerns.
When to be concerned about night sweats
According to Mandal, night sweats by themselves aren't always a cause for concern.
That's especially true if they're happening for a common reason - like if you're going through menopause or taking SSRIs. However, if you're experiencing other symptoms as well, your night sweats could indicate a bigger problem.
"If they are accompanied by fever, weight loss, general malaise, or change in appetite, then it's time to get checked out by your primary care physician," Mandal says.
Insider's takeaway
Night sweats may be caused by a number of reasons including menopause, hormonal disorders, infection, and the side effects of certain medications like migraine medications and hormone-blocking medications. You shouldn't be concerned if you have occasional night sweats, but you should see your doctor if it's accompanied by fever, weight loss, or changes in appetite.