Night sweats affect roughly 10% to 41% of adults in primary care settings, with the highest rates showing up in men between 41 and 55 years old. Most of the time, the cause is something fixable: a warm bedroom, stress, medication, or a hormonal shift. Occasionally, night sweats point to something that needs medical attention.
Your Bedroom Might Be Too Warm
Before looking for a medical explanation, start with the simplest one. Your body temperature naturally drops during sleep, and if your environment fights that process, you’ll sweat. The ideal bedroom temperature for sleep is 60 to 67°F (15 to 19°C). That feels cool to most people when they’re awake, but it’s what your body wants once you’re asleep.
Heavy blankets, memory foam mattresses (which trap heat), synthetic sleepwear, and a partner or pet in the bed all raise the temperature around your skin. Alcohol before bed is another common trigger: it dilates blood vessels near the skin’s surface, making you feel warm and triggering sweat as your body tries to cool down. If you’re waking up damp but not drenched, and it only happens some nights, the fix may be as simple as turning down the thermostat, switching to lighter bedding, or cutting out that last drink.
Low Testosterone and Male Hot Flashes
Men don’t often associate hot flashes with themselves, but low testosterone is a well-documented cause of night sweats. The thermal control center in the hypothalamus, the part of the brain that regulates body temperature, becomes unstable when testosterone levels drop. The nervous system sends out signals that widen blood vessels in the skin, producing a flush of warmth. To counter that spike in skin temperature, the body rapidly converts the warm flush into a cold, clammy sweat.
This is the same basic mechanism behind menopausal hot flashes in women, just driven by a different hormone. In men, testosterone can decline gradually with age (sometimes called andropause), or drop sharply after certain medical treatments. If your night sweats come with fatigue, reduced sex drive, difficulty concentrating, or mood changes, low testosterone is worth investigating with a simple blood test.
Sleep Apnea Is a Surprisingly Common Cause
Obstructive sleep apnea, where your airway repeatedly collapses during sleep, is far more likely to cause night sweats than most people realize. In one study published in the European Respiratory Journal, 31% of people with obstructive sleep apnea reported frequent night sweats (three or more times per week), compared to just 11% of the general population.
The connection makes sense: each time your airway closes, your body goes into a mini stress response. Your heart rate spikes, stress hormones surge, and your nervous system activates the same fight-or-flight pathways that trigger sweating. If you snore loudly, wake up gasping, feel unrested despite a full night’s sleep, or your partner has noticed you stop breathing, sleep apnea could be driving both your fatigue and your night sweats. Treating the apnea often resolves the sweating.
Stress, Anxiety, and Nocturnal Panic Attacks
Chronic stress keeps your nervous system running in a heightened state, and that doesn’t always switch off when you fall asleep. Elevated stress hormones can trigger sweating throughout the night even without waking you up. But in some cases, the response is more dramatic.
Nocturnal panic attacks are sudden surges of fear that jolt you out of sleep. You wake in a state of panic with a racing heart, profuse sweating, and difficulty breathing. Research suggests that people who have panic attacks at night tend to experience more severe breathing symptoms than those who have them during the day, which can make the experience feel like a heart attack. These episodes aren’t caused by nightmares (they typically happen during non-dreaming sleep stages) and can occur even if you’ve never had a daytime panic attack. If you’re waking up suddenly with your heart pounding and your sheets soaked, and the episodes pass within 10 to 20 minutes, this is a likely explanation.
Medications That Cause Sweating
Several common medications list excessive sweating as a side effect, and antidepressants are among the biggest culprits. SSRIs and SNRIs, the two most widely prescribed classes of antidepressants, cause sweating in 7% to 19% of patients. The sweating can happen day or night, but many people notice it most when they’re trying to sleep because there’s nothing else masking the sensation.
Other medications linked to night sweats include blood pressure drugs, diabetes medications that can cause low blood sugar overnight, and over-the-counter fever reducers like aspirin or acetaminophen (which work by resetting your body’s thermostat and can trigger rebound sweating). If your night sweats started around the same time you began a new medication, that timing is worth mentioning to your prescriber. Adjusting the dose or switching to a different option often helps.
Infections and Immune Responses
Night sweats are one of the body’s tools for fighting infection. Any illness that produces a fever can cause sweating at night as your temperature fluctuates. This includes common viral infections that resolve on their own. But certain chronic infections are specifically known for causing persistent, drenching night sweats.
Tuberculosis is the classic example. Active TB causes night sweats alongside a persistent cough, weight loss, and fatigue, with symptoms that build gradually over weeks. Other bacterial infections, including heart valve infections (endocarditis) and bone infections, can also present with night sweats as an early sign. HIV is another infection where night sweats are a recognized symptom, particularly in untreated disease. If your night sweats are new, persistent, and accompanied by fever, weight loss, or a cough that won’t quit, an infection screen is a reasonable step.
When Night Sweats Signal Something Serious
Night sweats are occasionally an early sign of cancer, particularly lymphoma and leukemia. But the character of the sweating matters. Cancer-related night sweats tend to be drenching, the kind where you need to change your clothes or bedsheets. They’re persistent rather than occasional, and they almost always come alongside other symptoms: unexplained weight loss (typically more than 10 pounds), persistent fevers, fatigue, or unusual bruising.
These three symptoms together, night sweats, fever, and weight loss, are known as “B symptoms” in the context of lymphoma, and they carry specific diagnostic significance. Mild sweating that happens a few times a month without any other changes is far less concerning than nightly drenching sweats paired with a 15-pound weight loss you can’t explain. The distinction between “I woke up a little warm” and “I had to strip the bed” is one that doctors take seriously when evaluating the cause.
Practical Steps to Reduce Night Sweats
Keep your bedroom between 60 and 67°F. Use breathable bedding materials like cotton or bamboo rather than synthetics. Avoid alcohol within three hours of bedtime, since it dilates blood vessels and disrupts temperature regulation. Regular exercise helps regulate stress hormones and improves sleep quality, but finish intense workouts at least two to three hours before bed, because the temporary rise in core body temperature can trigger sweating if you go to sleep too soon after.
If the sweats persist despite these changes, keep a simple log for a couple of weeks: how often they happen, how severe they are (damp vs. drenching), and whether you notice any other symptoms like weight changes, fatigue, or mood shifts. That information helps narrow the cause quickly and gives a clinician something concrete to work with. Night sweats are common and usually manageable, but persistent drenching sweats paired with other unexplained symptoms deserve a closer look.