Night sweats in men are common and usually caused by something fixable: a warm bedroom, alcohol before bed, or a medication side effect. But when sweating is heavy, frequent, or accompanied by other symptoms, it can signal hormonal changes, sleep apnea, or less common conditions that deserve medical attention.
How Your Brain Controls Temperature During Sleep
Your body naturally cools down as you fall asleep. A region of the brain called the preoptic hypothalamus serves double duty: it initiates deep sleep and coordinates body cooling at the same time. When warmth signals arrive from your skin, specialized neurons trigger blood vessels near the surface to widen, releasing heat. This is why your core temperature drops during the first half of the night.
This system works well under normal conditions, but it can misfire. If your bedroom is too warm, your body ramps up sweating to compensate. If something internal, like a hormone shift or infection, disrupts the hypothalamus’s thermostat, your brain may trigger a cooling response even when you don’t need one. The result is waking up damp or drenched, sometimes with sheets soaked through.
Low Testosterone and Male Hot Flashes
Most men associate hot flashes with menopause, but low testosterone produces the same effect. When sex hormone levels drop, the hypothalamus becomes more sensitive to small temperature changes and overreacts. It sends signals that rapidly widen blood vessels in the skin, creating a sudden flush of warmth. Your body then counters with a cold, clammy sweat to bring the temperature back down. Harvard Health describes this as a direct consequence of reduced sex hormone activity on the brain’s thermal control center.
Testosterone levels naturally decline with age, roughly 1% per year after 30, but the drop is usually gradual enough that most men don’t get night sweats from aging alone. More dramatic drops happen with certain medical treatments (particularly hormonal therapy for prostate cancer), obesity, chronic stress, or conditions affecting the testes or pituitary gland. If night sweats started recently and you’re also noticing lower energy, reduced sex drive, or mood changes, testosterone could be the thread connecting them.
Sleep Apnea Is a Surprisingly Common Cause
Obstructive sleep apnea, where the airway repeatedly collapses during sleep, is one of the most overlooked causes of night sweats in men. In one study published in the European Respiratory Journal, 31% of people with sleep apnea reported frequent night sweats (three or more times per week), compared to just 11% of the general population. That’s nearly triple the rate.
The connection makes sense physiologically. Each time your airway closes, your body goes into a mini stress response: heart rate spikes, blood pressure surges, and the nervous system activates as if you’re in danger. That burst of fight-or-flight activity generates heat and triggers sweating. Many men with sleep apnea don’t realize they stop breathing during the night, so they attribute the sweating to the room being too warm or eating too late. If you snore heavily, wake up with headaches, or feel exhausted despite a full night in bed, sleep apnea is worth investigating.
Alcohol, Diet, and Evening Habits
Alcohol is one of the most straightforward causes of nighttime sweating. It increases your heart rate and widens blood vessels in the skin, both of which raise skin temperature and trigger perspiration. This happens whether you’ve had two drinks or six, though heavier drinking makes it worse. The effect intensifies as your body metabolizes alcohol during the second half of the night, which is why you might fall asleep fine and wake up sweating hours later.
Spicy food, caffeine, and large meals close to bedtime can also push your body’s thermostat in the wrong direction. Capsaicin (the compound that makes peppers hot) directly activates the same heat receptors in your body that respond to actual temperature increases. Caffeine raises your metabolic rate. And digesting a heavy meal generates enough internal heat to disrupt the natural cooling process your body relies on to stay asleep comfortably.
Medications That Cause Night Sweats
Several common medications list night sweats as a side effect. The Mayo Clinic identifies these categories as frequent culprits:
- Antidepressants: SSRIs and other depression medications are among the most common drug-related causes of night sweats. The effect can start within the first few weeks of treatment.
- Hormone therapy: Medications that lower testosterone or other hormones, particularly those used in prostate cancer treatment, directly affect the brain’s temperature regulation.
- Blood sugar medications: Drugs that lower blood sugar can sometimes push levels too low during the night, triggering sweating as part of the body’s alarm response.
- Opioid-related medications: Methadone and similar drugs are well-known triggers.
If your night sweats started around the same time you began a new medication, that timing is worth noting. Don’t stop taking a prescribed medication on your own, but bring up the connection at your next appointment.
Low Blood Sugar During Sleep
For men with diabetes, nighttime sweating can be a sign that blood sugar is dropping too low while they sleep. Nocturnal hypoglycemia, generally defined as blood sugar falling below 70 mg/dL, triggers a stress hormone response that produces sweating, nightmares, and restless sleep. You might wake up with damp sheets, feel confused or irritable in the morning, or notice unexplained fatigue even after sleeping enough hours.
This is more likely if you take insulin or certain oral diabetes medications, skip an evening snack, or exercise heavily in the afternoon or evening. A continuous glucose monitor can catch these overnight dips, but even checking your blood sugar when you wake up sweating can provide useful data to share with your care team.
Red Flags That Need Attention
Most night sweats in men have a benign, correctable cause. But certain patterns warrant prompt evaluation. Night sweats that are drenching (soaking through your clothes and sheets), unexplained weight loss, persistent fevers, swollen lymph nodes in your neck, armpit, or groin, or new bone or chest pain can be signs of lymphoma, tuberculosis, HIV, or other serious conditions. These are rare causes, but they’re the ones where early detection makes the biggest difference.
When the cause isn’t obvious from your history and a physical exam, initial testing typically includes a complete blood count, thyroid function, tuberculosis screening, HIV testing, and inflammatory markers. A chest X-ray may also be part of the workup. If sleep apnea is suspected, a sleep study (polysomnography) is the standard diagnostic tool, and many can now be done at home.
Simple Fixes That Actually Help
Before pursuing medical workups, it’s worth optimizing the basics. The Sleep Foundation recommends keeping your bedroom between 60 and 68 degrees Fahrenheit for ideal sleep. Use a fan, open windows, or adjust the thermostat. Moisture-wicking sheets and breathable sleepwear make a noticeable difference for men who run warm.
Beyond temperature, cut off alcohol at least three hours before bed. Move heavy meals and intense exercise earlier in the evening. If you’re taking a medication that could be contributing, track your symptoms for two to three weeks so you have concrete data for your doctor. For many men, these changes alone are enough to solve the problem. When they’re not, the pattern of what does and doesn’t help becomes valuable diagnostic information in itself.