Night sweats in men have a wide range of causes, from something as simple as a warm bedroom to conditions that need medical attention like low testosterone, sleep apnea, or lymphoma. The term refers to repeated episodes of heavy sweating during sleep, enough to soak through your sheets or pajamas, not just feeling a little warm on a hot night. Understanding the most likely triggers can help you figure out whether yours are worth investigating.
Low Testosterone and the Brain’s Thermostat
The most common hormonal cause of night sweats in men is low testosterone, also called hypogonadism. Testosterone levels naturally decline with age, dropping roughly 1% per year after age 30, and when they fall far enough, the brain’s temperature control center in the hypothalamus can malfunction. Scientists don’t fully understand the mechanism, but the result is clear: the nervous system sends signals that widen blood vessels in the skin, producing a sudden flush of warmth. To counteract that rise in skin temperature, the body rapidly converts a warm flush into a cold, clammy sweat.
This is the same basic process behind hot flashes in women during menopause. In men, it’s most dramatic during androgen deprivation therapy for prostate cancer, which drops testosterone to very low levels. But it also happens with natural age-related decline, pituitary gland problems, or testicular conditions that reduce hormone output. If night sweats come alongside low energy, reduced sex drive, or difficulty concentrating, low testosterone is a strong suspect.
Sleep Apnea
Obstructive sleep apnea is an underrecognized cause of night sweats in men, and roughly 30% of people with sleep apnea report experiencing them. The connection appears to be oxygen deprivation: when your airway collapses repeatedly during sleep, your blood oxygen drops, and research has found that night sweats are significantly and independently associated with a higher burden of low oxygen in sleep apnea patients. Frequent awakenings also ramp up your sympathetic nervous system (the fight-or-flight response), which drives sweating.
If you snore heavily, wake up gasping, or feel exhausted despite a full night’s sleep, sleep apnea may be behind your night sweats. Treating the apnea, typically with a CPAP machine, often resolves the sweating as well.
Alcohol and Diet
Drinking alcohol before bed is one of the most straightforward triggers. Alcohol increases your heart rate and widens blood vessels in your skin, which triggers perspiration. Even moderate drinking can do this, and the effect is more pronounced with heavier consumption. The sweating tends to happen as your body metabolizes the alcohol, often in the second half of the night.
Spicy food and caffeine close to bedtime can have a similar vasodilating effect, though usually milder. If your night sweats only happen on nights you drink or eat heavily, the cause is likely environmental rather than medical.
Medications That Cause Night Sweats
Several common drug classes can trigger nocturnal sweating. The most frequent culprits are:
- Antidepressants: SSRIs and other depression medications are among the most common drug-related causes of night sweats, affecting a significant percentage of users.
- Diabetes medications: Drugs that lower blood sugar can cause overnight hypoglycemia, which triggers sweating as your body responds to the drop.
- Hormone therapy: Testosterone-blocking treatments for prostate cancer are a well-known cause, but other hormonal medications can also be responsible.
- Opioid-related medications: Methadone and similar drugs used in addiction treatment are associated with night sweats.
If your night sweats started around the same time you began a new medication, that timing is a strong clue. Don’t stop any medication on your own, but it’s worth raising the connection with whoever prescribed it.
Infections
Certain infections are classic causes of drenching night sweats. Tuberculosis is the most well-known, where sweating at night is considered a hallmark symptom alongside fever, weight loss, fatigue, and a persistent cough. HIV infection can also cause night sweats, particularly as the disease progresses. Bacterial infections of the heart valves (endocarditis) and bone infections are other, less common possibilities.
Infection-related night sweats rarely appear in isolation. They almost always come with other symptoms like fever, chills, unexplained weight loss, or prolonged fatigue. If you’re experiencing that combination, it warrants prompt evaluation.
When Night Sweats Signal Something Serious
The concern most men have when searching this topic is cancer, and it’s worth addressing directly. Lymphoma is the malignancy most strongly associated with night sweats. The sweats linked to lymphoma are typically described as “drenching,” meaning you wake up needing to change your clothes or sheets. They’re also rarely the only symptom. The classic warning pattern includes drenching night sweats plus unexplained weight loss (more than 5% of your body weight over six to twelve months) plus fever. Swollen lymph nodes in the neck, armpits, or groin, persistent fatigue, and itchy skin are other red flags.
Night sweats alone, without these accompanying symptoms, are not considered a strong predictor of cancer. That said, easy bruising, unexplained bleeding, or swollen nodes that persist longer than four to six weeks are signs that shouldn’t be ignored. A physician evaluating concerning night sweats will typically perform a thorough lymph node examination, check for fever and weight changes, and order blood work to look for signs of infection or blood cell abnormalities.
Autonomic Nervous System Problems
Your autonomic nervous system controls sweating automatically, without any conscious input. Conditions that disrupt this system can cause sweating that seems to come out of nowhere. Spinal cord injuries are one example, where a trigger below the level of injury (even something as minor as a full bladder or tight clothing) can set off a cascade of automatic responses including sweating and a spike in blood pressure. Diabetes-related nerve damage and certain neurological conditions can also dysregulate sweating patterns, sometimes causing heavy perspiration on one side of the body or in specific zones.
Managing Night Sweats at Home
While you work on identifying the underlying cause, a few environmental adjustments can reduce the severity. Keep your bedroom between 60 and 67°F (15 to 19°C), which is the range sleep specialists recommend for optimal rest. Choose breathable fabrics for both pajamas and sheets, since synthetic materials trap heat against your skin. Cotton or moisture-wicking athletic fabrics work well.
Limit alcohol, caffeine, and spicy foods in the hours before bed. If you’re carrying extra weight, losing even a modest amount can improve both sleep apnea and hormonal balance, two of the most common causes. Regular exercise helps regulate your body’s thermostat, though vigorous workouts too close to bedtime can temporarily raise your core temperature and make sweating worse.
If your night sweats are persistent, happening multiple times a week for more than a few weeks, and you can’t connect them to an obvious cause like alcohol or a warm room, that pattern is worth bringing to a doctor. The evaluation is usually straightforward: a physical exam, a review of your medications, and basic blood work can rule out or identify the most common causes relatively quickly.