Cold sweats at night, known medically as nocturnal diaphoresis, happen when your body’s temperature regulation misfires during sleep. Unlike simply overheating because your blanket is too thick, true night sweats soak through your clothes or sheets regardless of your bedroom temperature. The causes range from completely harmless to worth investigating, and the pattern of your sweats often points toward the reason.
Overheating vs. True Night Sweats
The first thing to sort out is whether you’re actually experiencing night sweats or just sleeping too warm. If you kick off the covers and the sweating stops, your bedroom environment is the likely culprit. True night sweats drench your pajamas and bedding even when the room is cool. They can wake you up shivering in damp sheets, which is where that “cold sweat” feeling comes from: your body produced a wave of sweat, then the evaporation dropped your skin temperature rapidly.
If this happens once after a particularly stressful day or a night of drinking, it’s rarely concerning. When it happens repeatedly, several nights a week for more than a couple of weeks, it’s worth looking into the underlying cause.
Hormonal Shifts Are the Most Common Cause
For women in perimenopause or menopause, night sweats are one of the hallmark symptoms. The mechanism is well understood: when estrogen levels drop, your brain releases a surge of norepinephrine, a stress chemical that narrows your body’s “thermoneutral zone.” That zone is the range of temperatures your body considers comfortable. Normally it’s fairly wide, so minor fluctuations don’t trigger a response. When estrogen dips, the zone shrinks so dramatically that even a tiny increase in core temperature makes your brain think you’re overheating, triggering a full sweat response to cool you down.
This isn’t limited to women. Men with low testosterone (hypogonadism) can experience the same kind of temperature dysregulation. Thyroid problems, particularly an overactive thyroid, also ramp up your metabolism and heat production enough to cause drenching night sweats. Diabetes can contribute too, especially if blood sugar drops overnight, which triggers a stress hormone response that includes sweating.
Medications That Cause Night Sweats
Antidepressants are one of the most common medication-related causes. SSRIs and SNRIs cause excessive sweating in roughly 7 to 19% of patients, depending on the specific drug. If your night sweats started within a few weeks of beginning or changing an antidepressant, the timing is a strong clue. Other medications frequently linked to night sweats include hormone-blocking drugs used in cancer treatment, blood pressure medications, and over-the-counter fever reducers like aspirin or acetaminophen (which work by resetting your body’s thermostat and can trigger sweating as your temperature adjusts).
Sleep Apnea and Night Sweats
This connection surprises most people, but it’s one of the strongest in the research. About 31% of people with obstructive sleep apnea report frequent night sweats (three or more times per week), compared to just 11% of the general population. That’s a threefold difference. The likely explanation is that repeated episodes of oxygen deprivation during the night activate your sympathetic nervous system, the same fight-or-flight system that makes you sweat when you’re anxious or exerting yourself.
The good news: when sleep apnea patients used a CPAP machine consistently, their rate of frequent night sweats dropped from 33% to about 12%, essentially matching the general population. If you snore heavily, wake up gasping, or feel exhausted despite a full night’s sleep, sleep apnea may be driving both your fatigue and your sweating.
Anxiety, Stress, and Mental Health
Panic attacks don’t only happen during the day. Nocturnal panic attacks can jolt you awake with a racing heart, a sense of dread, and cold sweats. Depression and post-traumatic stress disorder are also associated with night sweats, likely because they affect the same stress-hormone pathways that regulate body temperature. If you’re going through a period of intense stress or have a diagnosed anxiety disorder, your nervous system may simply be running hotter at night than it should.
Alcohol and Evening Eating
Alcohol is a reliable trigger for night sweats, and the reason is counterintuitive. Drinking causes your blood vessels near the skin to widen, which makes you feel warm temporarily but actually pulls heat away from your core. As your core temperature drops, your body overcorrects by sweating, trying to shed heat through the skin even though your internal temperature is already falling. It’s an inefficient feedback loop, and it tends to hit hardest in the second half of the night as your body metabolizes the alcohol.
Spicy food and heavy meals close to bedtime can also trigger sweating. Gastroesophageal reflux disease (GERD) is specifically linked to night sweats, likely because the discomfort and autonomic response to acid reflux activates your nervous system during sleep.
Less Common but Serious Causes
Night sweats are an early symptom of certain infections and cancers, which is why persistent, unexplained sweating deserves medical attention. Tuberculosis, HIV, and heart valve infections (endocarditis) all classically cause drenching night sweats. Among cancers, lymphoma is the one most strongly associated with night sweats, often accompanied by unexplained weight loss and swollen lymph nodes.
These causes are far less common than hormones, medications, or sleep apnea. But if your night sweats are new, severe, unexplained by any obvious trigger, and accompanied by weight loss, fever, or persistent fatigue, those are the red flags that warrant blood work and further evaluation.
Figuring Out Your Trigger
Start by ruling out the obvious. Track your bedroom temperature, bedding weight, alcohol intake, and any medications you take. Keep a simple log for two weeks noting which nights you sweat and what was different about those days. Patterns often emerge quickly: sweating only on nights you drink, only since starting a new medication, or clustering around your menstrual cycle.
If no environmental or lifestyle factor explains it, the next step is a conversation with your doctor that includes blood work to check thyroid function, blood sugar, and hormone levels. If you have any signs of sleep apnea, a sleep study can confirm or rule it out, and treatment often resolves the sweating entirely. For medication-related sweats, adjusting the dose or switching to a different drug in the same class frequently helps.
Night sweats are disruptive and uncomfortable, but in most cases the cause is identifiable and treatable. The key detail is persistence: a few isolated episodes are normal, but sweats that soak your sheets multiple nights a week are your body signaling that something specific is off.