Night sweats happen when your body produces enough sweat during sleep to soak through your clothes or sheets, and they affect a surprisingly wide range of people for reasons that span from a too-warm bedroom to underlying health conditions. Most causes are harmless and fixable, but persistent, drenching night sweats can sometimes signal something that needs medical attention.
Your Bedroom Might Be Too Warm
The simplest explanation is often the right one. Sleep experts at the Cleveland Clinic recommend keeping your bedroom between 60 and 67°F (15 to 19°C). If your room is above 70°F, it’s too hot for quality sleep, and your body will sweat to compensate. Your core body temperature naturally dips during the night as part of your sleep cycle, and a warm room interferes with that process. Heavy blankets, memory foam mattresses that trap heat, and sleeping with a partner or pet all raise the temperature around your body.
Before looking for medical explanations, try lowering your thermostat, switching to lighter bedding, and sleeping in minimal clothing for a week. If the sweating stops, you have your answer.
Hormonal Changes During Perimenopause and Menopause
For women in their 40s and 50s, night sweats are one of the most common symptoms of the menopausal transition. An estimated 35% to 50% of perimenopausal women experience sudden waves of body heat with sweating and flushing that last 5 to 10 minutes, hitting both during the day and at night. These episodes happen because fluctuating estrogen levels disrupt the brain’s internal thermostat, narrowing the range of temperatures your body considers “normal.” Even a small rise in core temperature can trigger a full sweat response.
Hot flashes and night sweats typically continue for a year or two after menopause. In up to 10% of women, they persist for years beyond that. If night sweats are disrupting your sleep regularly, hormone therapy or other treatments can help, and the intensity usually decreases over time even without intervention.
Medications That Cause Sweating
Several common medications can trigger night sweats as a side effect, and many people don’t make the connection. Antidepressants are among the most frequent culprits. SSRIs like citalopram, escitalopram, fluoxetine, and paroxetine can cause sweating by affecting the part of the brain that regulates body temperature. Venlafaxine, a related antidepressant, is the single most reported medication for excessive sweating in adverse-event databases.
Other drug classes linked to night sweats include:
- Opioid pain medications like codeine, tramadol, and oxycodone, which trigger sweating through histamine release
- Steroid medications such as prednisone and dexamethasone, which influence hormone levels that regulate temperature
- Thyroid medications like levothyroxine, particularly if the dose is slightly too high
- Tricyclic antidepressants like amitriptyline and imipramine
If your night sweats started around the same time as a new medication or a dosage change, that’s a strong clue. Don’t stop taking a prescribed medication on your own, but it’s worth raising the timing with your prescriber. Adjusting the dose or switching to a different option in the same class often resolves the problem.
Blood Sugar Drops During the Night
People with diabetes, especially those taking insulin or certain oral medications, can experience a drop in blood sugar while sleeping. This is called nocturnal hypoglycemia, and it kicks in when blood glucose falls below 70 mg/dL. Your body treats low blood sugar as an emergency and floods you with stress hormones to push glucose back up. One of the most noticeable effects is hot, clammy, sweaty skin.
You might not fully wake up during these episodes. Clues that overnight low blood sugar is the cause include waking up with a headache, feeling unusually tired despite a full night’s sleep, or finding your pajamas or sheets damp in the morning. A continuous glucose monitor can catch these dips. If you suspect this is happening, adjusting the timing of your evening meal, your medication dose, or your bedtime snack can make a significant difference.
An Overactive Thyroid
Your thyroid gland produces hormones that control how fast your body burns energy and regulates temperature. When the thyroid is overactive (a condition called hyperthyroidism), it floods the body with too much of these hormones, speeding up your metabolism. The result is excess heat production throughout the day and night, which leads to sweating and increased sensitivity to warmth.
Night sweats from thyroid problems rarely show up alone. You’d typically also notice a faster heart rate, unexplained weight loss, anxiety or nervousness, and feeling warm when others around you are comfortable. A simple blood test can check your thyroid hormone levels, and the condition is very treatable once identified.
Infections and Immune Responses
Your body raises its temperature to fight off infections, and the sweating that follows is how it cools back down. Short-term illnesses like the flu or COVID-19 commonly cause a few nights of sweating that resolve as you recover. But certain chronic infections produce night sweats that last weeks or longer. Tuberculosis is the classic example, though it’s uncommon in many countries. HIV, endocarditis (an infection of the heart valves), and abscesses can also cause recurring night sweats paired with fevers.
Infection-related night sweats almost always come with other symptoms: fever during the day, fatigue, loss of appetite, or feeling generally unwell. If you’re otherwise healthy and just sweating at night, an infection is less likely to be the cause.
When Night Sweats Could Signal Something Serious
Lymphoma, a cancer of the immune system, is one of the more serious conditions associated with night sweats. The sweating tends to be drenching, soaking through sheets rather than just leaving you feeling warm. But it almost never occurs in isolation. The Mayo Clinic lists the key symptoms of lymphoma as swollen lymph nodes (usually painless lumps in the neck, armpit, or groin), persistent fatigue, unexplained weight loss, fever, and sometimes itchy skin or bone pain.
The combination of drenching night sweats, unintentional weight loss, and fever is what doctors call “B symptoms,” and it’s this cluster that raises concern. Night sweats on their own, without these accompanying signs, are far more likely to have a benign explanation. That said, if you’re experiencing soaking night sweats multiple times a week for more than two or three weeks, and you can’t point to an obvious cause like a warm room or a known medication, getting a basic workup with blood tests is reasonable.
Alcohol, Caffeine, and Evening Habits
Alcohol is a common and underappreciated trigger. Even moderate drinking in the evening causes blood vessels near the skin to dilate, which produces warmth and sweating as your body processes the alcohol overnight. Spicy food close to bedtime can do the same thing by temporarily raising your core temperature. Caffeine consumed in the afternoon or evening stimulates your nervous system and can increase sweat production hours later.
Intense exercise within two to three hours of bed also raises core body temperature enough to carry over into the first hours of sleep. If you work out in the evening, try shifting it earlier and see if your night sweats improve.
Practical Changes That Help
Start with the basics: set your thermostat between 60 and 67°F, and swap out heavy bedding for lighter options. Moisture-wicking sheets made from synthetic blends pull sweat away from your skin and let it evaporate, keeping you drier than cotton, which absorbs moisture but holds onto it. Flannel and other heavy cotton fabrics are particularly bad choices if you run hot. Look for lightweight, airy fabrics that allow heat to escape rather than trapping it against your body.
A fan or open window can improve airflow even if your room temperature is already in the right range. Wearing light, loose-fitting sleepwear (or none at all) helps your skin release heat. Keeping a glass of cold water by the bed won’t prevent sweating, but it helps you recover and fall back asleep faster after an episode.
If environmental changes don’t solve the problem, start keeping a simple log: when the sweating happens, how severe it is, what you ate or drank that evening, and any medications you take. This kind of record is enormously helpful for a healthcare provider trying to narrow down the cause. Most of the time, night sweats trace back to something identifiable and manageable, whether it’s a bedroom that’s too warm, a medication side effect, or a hormonal shift your body is working through.