Night sweats affect roughly 10 to 40 percent of adults, depending on the population studied, so if you’re regularly waking up damp or soaked, you’re far from alone. The causes range from a too-warm bedroom to hormonal shifts to medication side effects, and in rarer cases, an underlying medical condition worth investigating. Understanding the most likely explanations can help you figure out which category you fall into.
Your Bedroom May Be Too Warm
The simplest and most common reason for sweating in your sleep is an environment that’s warmer than your body needs. Your core temperature naturally drops during sleep, and if your surroundings fight that process, your body compensates by sweating. The recommended bedroom temperature for adults is 60 to 67°F (15 to 19°C), which feels cool to most people while they’re still awake. Heavy blankets, memory foam mattresses that trap heat, and synthetic pajamas can all push your effective sleeping temperature well above that range even if the thermostat looks fine.
If you’ve never measured your actual bedroom temperature at night, that’s the first thing to check. A simple thermometer on your nightstand can reveal whether your room creeps into the low 70s after you close the door, which is enough to trigger sweating in many people.
Medications That Cause Night Sweats
Several common medications list night sweats as a side effect, and many people don’t make the connection. Antidepressants are one of the most frequent culprits. Hormone therapy, drugs used to manage diabetes by lowering blood sugar, and methadone can also trigger sweating during sleep. If your night sweats started around the same time you began a new medication or changed your dose, that timing is a strong clue.
Stopping or switching medication on your own isn’t the answer, but knowing this connection exists means you can bring it up with your prescriber. In many cases, a dose adjustment or alternative medication resolves the problem.
Hormonal Changes and Estrogen
Hormones play a direct role in how your brain regulates temperature. Estrogen and progesterone help keep your internal thermostat stable, so when their levels rise or fall significantly, your body can lose that calibration. It responds the only way it knows how: sweating to cool down.
Low estrogen is one of the best-established causes of night sweats. This is why women going through perimenopause and menopause are disproportionately affected. Night sweats during these transitions are essentially the nighttime version of hot flashes, driven by the same hormonal shifts that make the brain’s temperature-control center overreact to small changes in body heat. But hormonal night sweats aren’t exclusive to menopause. Pregnancy, certain phases of the menstrual cycle, and conditions that affect hormone production in men (like low testosterone) can all have the same effect.
Alcohol and Food Before Bed
Drinking alcohol in the evening is a surprisingly potent trigger. Alcohol increases your heart rate and widens blood vessels in your skin, both of which drive heat to the surface and trigger perspiration. Even moderate drinking, a glass or two of wine with dinner, can be enough if you’re prone to it. The effect is strongest in the first few hours of sleep, when your body is still metabolizing the alcohol.
Spicy food and large meals close to bedtime can have a similar, though usually milder, effect. Digestion generates heat, and eating a big meal forces your body to do more metabolic work during a time when it’s trying to cool down.
Sleep Apnea and Other Sleep Disorders
Obstructive sleep apnea, a condition where your airway repeatedly collapses during sleep, is linked to night sweats. When your body struggles to breathe, it mounts a stress response that includes releasing adrenaline and raising your heart rate. That physiological alarm can trigger sweating even if you never fully wake up. People with untreated sleep apnea often report drenched sheets without realizing the sweating is connected to their breathing problems.
If your night sweats come alongside loud snoring, gasping during sleep, or feeling exhausted despite a full night’s rest, sleep apnea is worth considering. Treatment of the breathing problem typically reduces or eliminates the sweating.
Medical Conditions Worth Knowing About
A long list of medical conditions can cause night sweats, and while most are uncommon, some are important to recognize. Infections are one category. Tuberculosis is the classic example, but bacterial infections of the heart valves (endocarditis), pneumonia, HIV, and mononucleosis can all produce nighttime sweating, usually alongside other symptoms like fever, fatigue, or weight loss.
Endocrine conditions are another group. An overactive thyroid speeds up your metabolism, generating excess heat around the clock, including at night. Diabetes can cause night sweats through episodes of low blood sugar during sleep, which triggers an adrenaline surge.
Autoimmune diseases like rheumatoid arthritis and sarcoidosis occasionally produce night sweats as part of the body’s chronic inflammatory response. These conditions almost always come with other noticeable symptoms, so isolated night sweats without any other changes are unlikely to point here.
When Night Sweats Signal Something Serious
The word “drenching” matters. Waking up a little clammy is different from needing to change your sheets or pajamas. Lymphoma and other blood cancers can cause severe, soaking night sweats, but they almost always come with additional warning signs: unexplained weight loss, persistent fatigue, swollen lymph nodes (typically painless lumps in the neck, armpit, or groin), fevers, or bone pain. Hodgkin lymphoma in particular is known for the combination of drenching night sweats, fevers, and weight loss.
If you’re experiencing that cluster of symptoms, a doctor will typically start with a physical exam checking for swollen lymph nodes and an enlarged spleen or liver, followed by blood work and possibly imaging like a CT or PET scan. A lymph node biopsy is the definitive way to confirm or rule out lymphoma. But to put this in perspective: most people with night sweats do not have cancer. The vast majority have an environmental, hormonal, or medication-related explanation.
Figuring Out Your Specific Cause
Start with the low-hanging fruit. Drop your bedroom temperature to the 60 to 67°F range, switch to breathable bedding, and cut alcohol for a couple of weeks to see if anything changes. Check whether your night sweats started around the same time as a new medication.
If the sweating persists after you’ve addressed environmental factors, pay attention to the pattern. Is it worse at certain times of the month? Does it come with snoring or daytime fatigue? Are there any other symptoms like weight changes, fevers, or swollen glands? These details help narrow the possibilities significantly.
Persistent, unexplained night sweats, especially when they’re severe or paired with other symptoms, are worth a medical evaluation. A doctor will typically review your medications, check thyroid function and blood counts, and screen for infections or hormonal imbalances depending on your age, sex, and symptom profile. In most cases, the cause turns out to be identifiable and treatable.