Night sweats are surprisingly common and usually tied to something fixable, whether it’s your bedroom setup, a medication, or a hormonal shift. But when sweating is heavy enough to soak your sheets or wake you up regularly, it’s worth looking beyond your thermostat. The causes range from simple (too many blankets, a glass of wine before bed) to medical conditions that need attention.
Your Sleep Environment Might Be the Simplest Explanation
Before exploring medical causes, rule out the obvious. The National Sleep Foundation recommends a bedroom temperature of 60 to 67°F for optimal sleep. Some sleep researchers suggest an even narrower range of 60 to 65°F. If your room is warmer than that, or you’re sleeping under heavy bedding or wearing synthetic fabrics that trap heat, your body may simply be doing its job trying to cool you down.
Switching to breathable, moisture-wicking sheets and sleepwear, running a fan, or lowering the thermostat can resolve the problem entirely for some people. If those changes don’t help, the sweating likely has a deeper cause.
Hormonal Changes, Especially Around Menopause
Menopause is one of the most common reasons women experience drenching night sweats. As estrogen levels drop, the brain’s thermostat (located in the hypothalamus) becomes more sensitive. Normally, your body tolerates a range of small temperature fluctuations without reacting. But declining estrogen causes the brain chemical norepinephrine to narrow that comfort zone, so even a tiny rise in core body temperature can trigger a full-blown sweating response to dump heat.
This is why hormone therapy often helps: estrogen raises the temperature threshold at which the body decides it needs to sweat. Night sweats from menopause can start years before periods stop entirely, during perimenopause, and may persist for several years afterward. Men can experience a version of this too, as testosterone levels decline with age, though it tends to be less intense.
Medications You Might Not Suspect
Antidepressants are a well-documented trigger. People taking SSRIs are roughly three times more likely to report night sweats compared to those not on the medication. Other drug classes that commonly cause nighttime sweating include blood pressure medications, hormone therapies, steroids, and some diabetes drugs. If your night sweats started around the same time as a new prescription or dosage change, that connection is worth exploring with your prescriber.
Sleep Apnea Is an Overlooked Cause
Obstructive sleep apnea, a condition where your airway repeatedly collapses during sleep, has a strong link to night sweats that many people don’t know about. In an Icelandic study of sleep apnea patients, about 31% of men and 33% of women with untreated sleep apnea reported frequent night sweats (three or more times per week), compared to just 9% of men and 12% of women in the general population. That’s roughly a threefold increase.
The encouraging finding: once patients started using a breathing device during sleep, their sweating dropped back to normal population levels. If you also snore heavily, wake up gasping, or feel exhausted despite a full night’s sleep, sleep apnea could be the underlying issue driving your sweats.
Anxiety, Stress, and Panic
Your nervous system doesn’t fully shut off during sleep. Chronic anxiety and stress can keep your sympathetic nervous system (the “fight or flight” system) more active than it should be at night, and sweat glands become more responsive in people with acute or chronic anxiety. During a stress-driven sweat episode, you may notice your hands and feet feel cool or clammy rather than warm, because adrenaline constricts blood vessels in the extremities while triggering sweat glands elsewhere. Panic attacks can also occur during sleep, producing sudden intense sweating along with a racing heart and a sense of dread upon waking.
Low Blood Sugar Overnight
For people with diabetes, particularly those on insulin, blood sugar can drop dangerously low during the night. When that happens, the body releases adrenaline to raise glucose levels. That adrenaline surge causes sweating, a pounding heart, tingling, and anxiety. You might wake up drenched and shaky without knowing why. If you’re on diabetes medication and this pattern sounds familiar, your overnight blood sugar levels may need closer monitoring.
Alcohol and Its Rebound Effect
Drinking before bed initially lowers your core body temperature by dilating blood vessels near the skin. But as your body metabolizes the alcohol, a rebound effect kicks in: your temperature regulation becomes disrupted, and your circadian body temperature rhythm loses its normal pattern. Animal research has shown that alcohol administered in the evening produces a dose-dependent disruption of the body’s temperature cycle, with a hyperthermic rebound (a swing back toward overheating) during the night. Even moderate drinking can produce noticeably sweatier sleep, and the more you drink, the more pronounced the effect.
Infections and Immune Responses
Night sweats that come on suddenly and persist alongside other symptoms can signal an infection. Tuberculosis is historically the most well-known cause, and the reason the sweating happens preferentially at night is thought to involve the body’s cortisol rhythm. Cortisol, which suppresses immune activity and fever, is at its lowest in the predawn hours. With less cortisol to keep the immune response in check, the body’s inflammatory reaction to infection ramps up, producing fever and sweating while you sleep.
Other infections linked to night sweats include endocarditis (infection of the heart’s inner lining), bone infections, abscesses, and HIV. These are less common than hormonal or medication-related causes, but they’re important to consider if sweats are accompanied by fever, fatigue, or unintentional weight loss.
Thyroid Problems and Other Endocrine Issues
An overactive thyroid revs up your metabolism, raising your baseline body heat production. This makes sweating more likely both day and night, but it can be especially noticeable during sleep when you’d normally expect your body to cool down. Other signs include unexplained weight loss, a rapid or irregular heartbeat, and feeling jittery or anxious. Less commonly, a rare adrenal gland tumor called a pheochromocytoma can cause episodic surges of adrenaline that produce sudden sweating, rapid heart rate, and high blood pressure.
When Night Sweats Deserve Prompt Attention
Most night sweats turn out to have a manageable, non-serious cause. But certain patterns warrant a closer look. Pay attention if your night sweats are accompanied by unexplained weight loss of more than 10 pounds, persistent fevers, swollen lymph nodes that don’t go away, or severe fatigue. This combination, sometimes called “B symptoms” in medical settings, can be associated with blood cancers like lymphoma. In a review of urgent referrals at St Bartholomew’s Hospital in London, patients who had sweats alongside swollen lymph nodes or abnormal blood counts were categorized differently from those with sweating alone, reflecting the added concern those combinations carry.
Night sweats that are new, worsening, and unexplained by any obvious lifestyle factor are worth bringing up at your next appointment. A basic workup, typically blood tests checking thyroid function, blood sugar, infection markers, and a blood count, can rule out most of the serious possibilities relatively quickly.