Nobody wants to wake up sweating in the middle of the night. It hampers your sleep quality, stresses you out, and leaves a mess. And then you’re left wondering what’s causing the night sweats… Is it hormonal shifts from menopause? An infection? Cancer? Something else?
The positive news is that night sweats don’t usually indicate a grave problem. But nonetheless, it may take work to identify and solve the issue.
Night sweats are really common. One study found that 41% of primary care patients (aka most people) had at least one episode in the prior month. Most of them hadn’t told their doctor about it.
I hear from lots of women struggling with night sweats because hot flashes and sweating are textbook menopause symptoms. During perimenopause (the transition time before menopause), about 80% of women get hot flashes. This figure drops to 40% in the postmenopausal period, but that’s still not exactly low!
Even before menopause, women often struggle to stay cool and hydrated. (Thanks, hormones!) I’ll spend time explaining why this happens and share strategies to deal with it later in this article.
But even with the perfect strategy, we’ll never eliminate hot flashes, hormonal fluctuations, and other causes of night sweats. That said, we can identify the cause, take steps to address it, and rehydrate to mitigate the damage. To start: let’s talk about night sweats and what causes them.
What Are Night Sweats?
Night sweats are exactly what they sound like: sweat that occurs while sleeping. People with night sweats often wake up with damp sheets, pajamas, and pillows.
In everyday life, sweating brings down your core body temperature when it exceeds the normal range: the thermoneutral zone. Staying in this range keeps your bodily processes humming along smoothly. Accordingly, some cases of night sweats are due to overheating. As your body temperature rises, the hypothalamus (in the brain) triggers sweating to cool you down. There’s nothing pathological about it, and the fix simply entails a cooler room and fewer blankets.
But nighttime isn’t typically a time for sweating. Because body temperature tends to drop at night to promote restful sleep, we would expect less sweating during this time. And so, night sweats present a paradox. I keep my room chilly when I sleep, but I continue to wake up sweating. What’s going on?
The short answer is that night sweats may not be cooling you down properly… this may indicate a cooling system gone awry. So what causes that?
7 Night Sweats Causes
Thermoregulation involves the brain, hormones, the circulatory system, sweat glands, and the environment. Yes, maintaining your body temperature is complicated.
And so night sweats aren’t always easy to decode. For clues, let’s examine what’s linked to night sweats.
Before, during, and after menopause, many women experience rapid, transitory elevations in core body temperature. These “hot flashes” can happen at night and leave a wake of perspiration.
My heart goes out to all the women experiencing insomnia and other sleep disturbances during this frustrating time. It’s hard to sleep well when you keep waking up hot and sweaty. And it’s hard to feel your best when you aren’t sleeping well.
Before menopause, the menstrual cycle affects thermoregulation in other ways. For instance, during the luteal phase (directly after ovulation), women have higher skin temperatures and more significant sweat loss. I’ll talk more about that later.
#2: Hormonal issues
Menopause isn’t the only set of hormonal shifts that influence sweating. Hyperthyroidism, for instance, can elevate metabolic rate, raise body temperature, and cause night sweats.
Any disruption to the endocrine system can disrupt thermoregulation. The endocrine system is the network of glands, organs, and hormones regulating many bodily functions. So diabetes, sex hormone imbalances, pheochromocytoma (cancer of the adrenal gland), carcinoid syndrome (slow-spreading tumors that make hormones), and hypothalamic dysfunction can all disrupt the endocrine system.
Many can trace their night sweats back to drugs, supplements, or alcohol. Drugs that list sweating as a side effect include:
- SSRIs (a type of antidepressant)
- Blood sugar medications like insulin
- Proton pump inhibitors (for acid reflux)
- Pain pills
- And others
Then there’s alcohol. Alcohol elevates core body temperature and can also cause nausea-induced sweating.
People with hyperhidrosis sweat excessively even when their body doesn’t need cooling. The condition—which often begins in childhood—can result in social anxiety, embarrassment, and depression. Primary hyperhidrosis (the type defined by an unknown cause) doesn’t usually occur at night, but secondary hyperhidrosis (caused by medications, stress, illness, etc.) definitely can.
When fighting a pathogen, your core temperature rises. This fever helps fight the infection by enhancing immune cell function, and making it more challenging for viruses and bacteria to replicate.
Feverish sweating, in turn, can cause fluid and electrolyte imbalances. Because of this, it’s crucial to rehydrate with water and sodium when ill.
#6: Low blood sugar
Sweating is a textbook symptom of hypoglycemia (low blood sugar). To avoid hypoglycemia, people with diabetes must be careful with insulin, metformin, and other blood sugar medications, especially if fasting therapeutically. Work with your doctor on this one.
#7: Other causes of night sweats
Figuring out what’s causing your night sweats isn’t always easy. Here are some other potential causes:
- Anxiety, stress, or panic attacks that trigger the sympathetic nervous system
- A poor sleep environment (hot blankets in a warm room, etc.)
- Chemotherapy, radiation, and other forms of cancer treatment
- Gatroesopogheal reflux disease (GERD)
- Hot flashes during and after pregnancy
- Heart failure
Lots of possibilities, I know. Your doctor will probably want to run some tests to see what’s happening. Even if you can’t pinpoint the cause of your night sweats, you can still improve your sleep environment, reduce stress, and hydrate properly. Let’s talk about those strategies now.
Night Sweats: Treatment Strategies
How can you prevent and mitigate night sweats? Try these simple steps.
Optimize your sleep environment
Humans sleep best in a cool room. A cool room promotes lower core body temperature for better sleep and less nocturnal sweating. Optimal temperature ranges will vary (mine is in the mid-60s), but colder is better than warmer because you can always add more covers. Play with your blanket set up until you’re cool yet comfortable.
If you continue to struggle with temperature (perhaps with a partner who runs hot), you might look into a cooling mattress or mattress topper. These devices (Ooler, Eight sleep, etc.) aren’t cheap but seem to help many people.
Stress stimulates the sympathetic nervous system and increases sweating. To activate the parasympathetic (calming) nervous system, do what you can to de-stress before bed. Meditation, light stretching, and avoiding the email inbox are good things to practice, for starters. Also, controlled breathing was shown to significantly reduce hot flashes in postmenopausal women.
Think about medications
First, consider if any medication or supplement you’re taking might be causing your night sweats. It’s a common side effect. And if you’ve exhausted all of your other options, you might also try medications (like hormone therapies) to reduce night sweats. These medications have downsides, so talk to your doctor to weigh the pros and cons.
Staying Hydrated After Sweating
Every time you sweat, you lose water and sodium. You lose a smidge of potassium, magnesium, and other molecules too, but mostly you’re losing salty fluid.
If you don’t replace what you lose, you risk dehydration, low sodium, and the less-than-fun symptoms that come with them: fatigue, brain fog, muscle cramps, weakness, and a lack of energy.
Most people rehydrate with water alone, neglecting to replace sodium. From a young age, many of us have been brought up to love water and avoid salt! As a result, many people (especially athletes) over-hydrate with plain water and develop dangerously low blood sodium levels. This sometimes-fatal condition is called hyponatremia.
Women are at higher risk for exercise-associated hyponatremia than men. Why? Researchers aren’t sure, but here are some possible explanations:
- Women drink more fluids during training and competition because they tend to have longer race times
- Women have lower body mass indexes than men (less leeway with fluid intake)
- Elevated progesterone during the luteal phase (directly after ovulation) increases sodium loss through urine
- Progesterone also increases antidiuretic hormones, making it harder to excrete excess fluids
I find these differences fascinating, but the bottom line is that anyone with night sweats needs to replace water and sodium. One easy solution? Mix a stick of LMNT into 32 ounces of water upon waking, stir, and enjoy. It’s got all the electrolytes for optimal rehydration with no sugar or other junk to derail your healthy lifestyle. Plus, LMNT tastes so good you’ll be bounding out of bed in the morning to mix a glass.
Nights Sweats Happen
Most of us will wake up sweaty at some point. If these sweats happen frequently, work with a medical professional to ascertain the cause, then take the appropriate steps to address it.
Even if you can’t figure out exactly what’s causing the night sweats, be sure to rehydrate with fluids and electrolytes. Your body will thank you for it.