Night sweats in men are most commonly caused by lifestyle factors like alcohol use, medications, or an overheated sleep environment, but they can also signal hormonal changes, sleep apnea, infections, or other medical conditions. Clinically, night sweats are defined as episodes of sweating during sleep that go beyond what’s needed to regulate body temperature, ranging from moderate dampness to drenching episodes that soak through sheets and bedclothes. If your bedroom is cool, your bedding is reasonable, and you’re still waking up wet, something else is driving it.
Low Testosterone and Hot Flashes
Men don’t typically think of hot flashes as something that happens to them, but low testosterone is one of the most common hormonal causes of night sweats. The thermal control center in the hypothalamus, the part of the brain that acts like an internal thermostat, appears to malfunction when testosterone levels drop. Scientists haven’t fully mapped the exact pathway, but the result is clear: the brain misreads your core temperature and triggers a cooling response (flushing, sweating) when none is needed.
This is especially common in men receiving hormone-suppression therapy for prostate cancer, but it also affects men whose testosterone declines naturally with age or due to conditions affecting the testes or pituitary gland. The sweating tends to come in waves, often with a sudden sensation of heat in the chest and face, followed by a chill as the sweat evaporates. If you’re in your 40s or older and noticing night sweats alongside fatigue, reduced sex drive, or mood changes, low testosterone is worth investigating.
Sleep Apnea
About 30% of people with obstructive sleep apnea report night sweats. The connection is oxygen: when your airway collapses repeatedly during sleep, your blood oxygen drops. Research published in the American Journal of Managed Care found that night sweats were significantly and independently associated with a higher burden of low oxygen levels in people with sleep apnea. The frequent awakenings and accompanying body movements ramp up your sympathetic nervous system (the fight-or-flight response), which increases sweating.
Compared to people without the condition, those with sleep apnea were roughly 50% more likely to report night sweats (about 19% versus 12%). If your night sweats come alongside loud snoring, gasping during sleep, or persistent daytime fatigue, sleep apnea may be the underlying issue rather than a standalone sweating problem.
Medications, Especially Antidepressants
Up to 22% of people taking antidepressants experience excessive sweating as a side effect. This occurs across all major classes of these medications, including SSRIs, SNRIs, and older tricyclic antidepressants. The sweating often worsens at night because your body’s temperature regulation shifts during sleep, making you more vulnerable to drug-induced disruptions.
Antidepressants aren’t the only culprits. Other medications commonly linked to night sweats include hormone therapies, blood pressure drugs, diabetes medications (particularly when blood sugar drops too low overnight), fever reducers like aspirin and acetaminophen, and steroids. If your night sweats started within a few weeks of beginning or adjusting a medication, that timing is a strong clue.
Alcohol and Substance Use
Alcohol widens blood vessels in your skin and increases heart rate, both of which trigger perspiration. Even moderate drinking in the evening can cause enough vasodilation to produce noticeable sweating a few hours later as your body processes the alcohol. The effect is more pronounced with heavier drinking.
Withdrawal is the other side of the equation. If you drink regularly and then stop or cut back, sweating, clammy skin, and night sweats are common withdrawal symptoms. This can happen even if you wouldn’t consider yourself dependent. The nervous system rebounds from the sedating effects of alcohol by becoming hyperactive, and sweating is one visible result.
Tobacco use is also independently linked to night sweats, though the mechanism is less well understood.
Thyroid Problems and Other Metabolic Causes
An overactive thyroid gland speeds up your metabolism, generating excess heat that your body tries to shed through sweating. Night sweats from hyperthyroidism usually come alongside other symptoms: unexplained weight loss, a rapid or irregular heartbeat, anxiety, tremors, and difficulty tolerating warm environments even during the day. If sweating is happening both day and night and you’ve noticed these other changes, thyroid function is a likely contributor.
Diabetes can also cause night sweats, particularly when blood sugar dips too low overnight. This is more common in men taking insulin or certain oral diabetes medications. The sweating in this case is part of a stress response as your body recognizes the low blood sugar and releases adrenaline to raise it. You may also notice shakiness, hunger, or a rapid heartbeat.
Obesity independently increases the risk of night sweats. Excess body weight acts as insulation, trapping heat that your body then tries to release through perspiration.
Anxiety, Depression, and Stress
Panic attacks can occur during sleep, producing sudden sweating, a racing heart, and a feeling of dread upon waking. Many men don’t realize that nocturnal panic attacks are a recognized phenomenon because they associate panic with daytime situations. Depression and post-traumatic stress disorder are also independently associated with night sweats, likely through their effects on the stress-response systems that regulate body temperature and sweating.
Chronic stress keeps cortisol and adrenaline elevated, and these hormones directly affect how your body manages heat. If your night sweats coincide with a period of high stress, poor sleep, or worsening mood, the connection may be psychological rather than purely physical.
Infections and Serious Illness
Tuberculosis and lymphoma are the two conditions most classically associated with drenching night sweats, though both are relatively uncommon causes in everyday medical practice. Hodgkin’s lymphoma in particular can produce weeks of high, fluctuating fevers with soaking night sweats, and for some patients, night sweats are the first and only symptom. Non-Hodgkin’s lymphoma and leukemia can also present this way.
Among infections, HIV is notable because fever with or without night sweats is the most common systemic complaint. Tuberculosis, fungal infections like histoplasmosis, heart valve infections (endocarditis), and even mononucleosis during its acute phase can all produce significant night sweats. These conditions almost always come with other symptoms: prolonged fever, unintentional weight loss, persistent cough, or profound fatigue.
When Night Sweats Are a Red Flag
For the vast majority of men, night sweats don’t represent a serious medical problem. They’re often traceable to a warm bedroom, alcohol, medication, or stress. But certain combinations of symptoms warrant prompt evaluation. New night sweats paired with unexplained weight loss, persistent fever, decreased appetite, swollen lymph nodes, or a new rash suggest something that needs medical attention sooner rather than later.
Night sweats that are truly drenching, the kind where you need to change your sheets, carry more diagnostic weight than mild dampness. The same is true for sweats that persist for weeks without an obvious explanation, especially if they’re getting worse. A basic evaluation typically starts with a physical exam, blood work to check thyroid function, blood sugar, hormone levels, and markers of infection or inflammation, and a detailed review of your medications and habits. In most cases, identifying and addressing the underlying cause resolves the sweating.