Night sweats in older men are most commonly caused by medications, hormonal shifts, sleep apnea, or lifestyle factors like alcohol. Less often, they signal an underlying infection or, rarely, cancer. The prevalence of night sweats in adults ranges from 10% to 41%, so if you’re waking up damp or drenched, you’re far from alone.
The cause matters, though, because the fix depends entirely on what’s driving the sweating. Here’s a breakdown of the most likely culprits, starting with the most common.
Medications Are a Leading Cause
If you started a new medication in the weeks or months before the sweating began, that’s the first place to look. Antidepressants are among the worst offenders: roughly 22% of people taking them experience excessive sweating as a side effect. SSRIs and SNRIs, the two most commonly prescribed classes, are particularly likely to cause it.
Other medications known to trigger night sweats include blood pressure drugs, hormone therapies, diabetes medications (especially insulin and drugs that lower blood sugar), steroids, and over-the-counter pain relievers like aspirin or acetaminophen when taken regularly. If the timing lines up with a medication change, that’s a strong clue. Your doctor can often adjust the dose or switch to an alternative.
Hormonal Changes After 40
Testosterone levels decline by about 1% per year after age 40. For most men, this gradual drop stays within the normal range and doesn’t cause symptoms. The exception is men undergoing androgen deprivation therapy for prostate cancer, where testosterone is deliberately suppressed to very low levels. In that group, 70% to 80% experience hot flashes, and those flashes are most common at night.
The mechanism works like this: low testosterone disrupts the brain’s thermostat, located in the hypothalamus. The nervous system misreads your body temperature, sending signals that widen blood vessels in the skin. You flush warm, and then your body overcorrects by producing a cold, clammy sweat. If you’re not on prostate cancer treatment but suspect low testosterone, other symptoms to watch for include fatigue, reduced muscle mass, low libido, and difficulty concentrating.
Sleep Apnea and Nighttime Breathing
Obstructive sleep apnea is common in older men and frequently overlooked as a cause of night sweats. About 30% of people with sleep apnea report night sweats, compared to roughly 12% of people without it. The connection appears to be linked to drops in blood oxygen that happen when breathing repeatedly stops during sleep. Your body responds to these episodes with stress hormones that trigger sweating.
If your night sweats come with loud snoring, gasping awake, morning headaches, or daytime sleepiness, sleep apnea is a strong possibility. The good news is that treating the apnea, typically with a CPAP machine, often resolves the sweating along with the other symptoms.
Alcohol and Other Lifestyle Triggers
Alcohol increases your heart rate and dilates blood vessels in the skin, both of which trigger sweating. This effect is amplified during sleep because your body is already working to regulate temperature in a confined, insulated environment. Even moderate drinking in the evening can be enough to cause noticeable night sweats in older men, whose thermoregulation is already less efficient than it was at 30.
Spicy food close to bedtime, caffeine, and an overly warm bedroom can compound the problem. These aren’t medical causes, but they’re worth ruling out before pursuing a workup for something more serious. Try eliminating evening alcohol for two weeks and keeping the bedroom at 65 to 68 degrees to see if the pattern changes.
Low Blood Sugar During Sleep
For men with diabetes, especially those taking insulin or medications that actively lower blood sugar, nighttime blood sugar drops are a well-known cause of sweating. Signs of overnight low blood sugar include waking up with damp sheets, having nightmares, and feeling unusually tired, irritable, or confused in the morning.
This is worth taking seriously because severe nighttime lows can be dangerous. If you’re on insulin or a sulfonylurea and noticing these symptoms, checking your blood sugar before bed and when you wake can help confirm the pattern. Adjusting your evening medication or having a small snack before sleep are common solutions.
Infections and Chronic Illness
Several infections cause night sweats as a prominent symptom. Tuberculosis is the classic example, but bacterial infections of the heart valves (endocarditis), bone infections, HIV, and certain fungal infections can all produce drenching sweats at night. These conditions almost always come with other symptoms: persistent fever, weight loss, fatigue, or localized pain.
Night sweats from infection tend to be more severe than those from medications or lifestyle factors, and they don’t resolve with environmental changes like cooling the bedroom.
When Night Sweats Could Signal Cancer
This is the possibility most people are worried about when they search for answers. Lymphoma, both Hodgkin and non-Hodgkin types, is the cancer most strongly associated with night sweats. But the pattern is specific and distinct from garden-variety sweating.
Cancer-related night sweats are drenching. You wake up soaked enough to change your nightclothes and sheets, often more than once per night. They recur persistently, not just occasionally. And they almost always appear alongside other symptoms: unexplained weight loss of 10% or more of your body weight, persistent fevers above 100.4°F that aren’t caused by an infection, and sometimes painless swollen lymph nodes. Oncologists refer to the fever, sweats, and weight loss combination as “B symptoms.”
If your night sweats are mild, intermittent, and not accompanied by weight loss or fever, cancer is far down the list of likely causes. If they are severe, persistent, and paired with any of those warning signs, that combination warrants prompt evaluation.
Sorting Out the Cause
Because the list of potential causes is long, a practical approach is to start with the most common and work down. Review any medications you’re taking, especially antidepressants, blood pressure drugs, and diabetes medications. Note whether you’re drinking alcohol in the evenings. Pay attention to your sleep quality: snoring, gasping, and daytime drowsiness point toward sleep apnea. Track whether the sweats are mild dampness or full sheet-soaking episodes, and whether they come with fever, weight loss, or other new symptoms.
That information makes a huge difference when you bring it to a doctor. Most night sweats in older men trace back to a medication, a treatable sleep disorder, or a lifestyle factor. The serious causes are less common, but they do exist, and distinguishing between the two often comes down to the pattern: how severe the sweating is, how often it happens, and what other symptoms come along with it.