Why Do You Sweat in Your Sleep?

July 22, 2022 | Casper Editorial Team

Waking up night after night drenched in a cold sweat is an actual nightmare come true. When you tuck in for the night, you should close your eyes to a comfy sleep environment and wake up to a fresh new day—not sweat-soaked sheets. 

You might be asking yourself, why do I sweat in my sleep? How do I stop this night sweating? 

There’s a wide range of reasons why you might be waking up feeling like you just ran the track. Whether it’s due to a spike in stress levels or a not-quite-right sleep environment, the culprit of night sweating could be different for each person.

Together, we can sniff out the problem. Follow along as we dive into four common causes of night sweats. Plus, we’ll show you how a few small changes could have you back to counting sheep, not changing sheets. 

4 Common Causes of Night Sweats and How to Manage Them 

One study found that 41% of people suffer from night sweats, most common in adults ages 41 to 55 years old.1  With so many different factors affecting sleep these days—from too much caffeine to too many naps—it might feel like a full-time job trying to find why your sweet dreams have turned into a sweat lodge.2 

Take a closer look at these common reasons for night sweats; the good night’s sleep you’ve been daydreaming about might be closer than you think.   

#1 Drinking Before Bedtime

Who doesn’t love a nice glass of wine or maybe a cold beer after a long hard day? Sometimes it’s just the thing you need to help you wind down and catch some Zzs, right?

Well, perhaps not

That’s because studies have found that consuming alcohol can cause increased sweating.3 Because alcohol raises the body temperature, even just a glass or two at night can greatly affect your sleep cycle. Alcohol also increases your heart rate and opens airways, both of which can kick up your body temp, leaving you warmer as you turn in for the night.  

The good news is that you don’t have to give up your nightcap completely to avoid nighttime sweating. There are a couple of simple steps you could take to ensure a dryer night’s sleep:

  • Try consuming your beverage of choice at least four hours before you turn in for the night. 
  • Another option is to drink down a glass of cold water right before bed or to keep one handy at your bedside throughout the night; it might help to better regulate your body temperature as you sleep. 

#2 Stress or Anxiety

As you drift off to sleep, are visions of sugar plums dancing in your head? Or do you find yourself remembering all of the things you forgot to do that day, fretting about the neverending list of things for tomorrow—and didn’t your Aunt Suzie want you to call her last week? 

An overactive mind is enough to make anyone break a cold sweat. 

Eliminating stress and finding relaxation is easier said than done, but here are a few tricks to help you reduce stress and establish an effective bedtime routine before you climb into bed: 

  • Avoid screens – You might think a casual scroll through your phone will help your brain shut off, but it’s actually the opposite. Electronic screens stimulate the brain4, making it harder to fall asleep—and let’s face it—so does seeing all your old high school classmates and their FOMO-inducing vacation pics. Sign off at least two hours before bed and avoid the scroll—trust us. 
  • Make a routine – Remember when you were a kid, and it was dinner, bath, book, and bed by 7 pm? Try embracing that—well, maybe not exactly that, but something like that. Going to bed and waking up at the same time, along with a relaxing nighttime routine, can help fix your sleep schedule to get into a more calm headspace and fall asleep without breaking a sweat. 
  • Check-in with your doc – Sleep is important, obviously. So, if you’ve tried everything to find your nightly zen and you’re still having trouble with true night sweats, then maybe avoid an apple for a day and check-in with your doctor. Trouble sleeping or excessive sweating at night due to stress could be a sign of underlying anxiety or mental health issues.5   

#3 Sleep Environment 

We’ve all done it, tossed our laundry on the bed to “fold later,” and then shoved it to one side. Or maybe, you’ve spent a long night with your laptop and woke up to your devices cuddled up next to you? 

Creating a space that is cool, calm, and comfortable is key to proper sleep hygiene, leading to a better nights sleep. 

To help you set the right mood before bedtime, be sure to factor in the following: 

  • Temperature – A 2012 study found that temperature really does play a role in our sleep cycle, so try dropping your thermostat a few degrees.6 Having a cooler room can help your body stay cool, sweat less, and sleep more deeply. 
  • Humidity – Once you nail the temp of your room, take a closer look at the level of humidity. The ideal range is between 30% and 50%, so grab a humidifier or dehumidifier and make sure you’re breathing easily.7  
  • Lighting – Turning down the lights as you get ready for bed is an easy way to signal to your brain and body that it’s time to rest. Dropping the lighting, or closing your blackout curtains two hours before bed could be the key to improving the quality of your rest. Adding soft nightlights to your hallways and bathroom are also a simple way of making  those nightly breaks less disruptive. 
  • Clothing – Those fuzzy fleece pajamas your loved one gifted you for your birthday could be the perfect loungewear for movie nights—but they might not be doing you any favors when it comes time for some shut-eye. If you tend to sleep hot, invest in lightweight pajamas with materials like polyester or rayon, giving you the best of both worlds: coziness and moisture management.
  • Bedding – If you’ve been changing your sheets frequently because of your true night sweats, maybe it’s time to really change them up. Bamboo or cotton sheets are absorbent and ultra-breathable. But if you really want to take your sleep to a cooler level, try out a set of sheets or a duvet designed specifically for hot sleepers. 
  • Mattress – Your mattress can play a major part in why you might be excessive sweating in the wee hours. Different memory foam mattresses hold air differently.8 A traditional memory foam mattress tends to trap heat, while open-cell memory foam and gel memory foam work to pull heat away from the body and keep body temps down. Or, if you’re not in the market for a new mattress quite yet, maybe give your bed a simple makeover with a cooling mattress cover.   

#4 Health-Related Issues

Your evening wine has been drunk by 7 pm, you’ve cut back on your nightly screen time, and your bedroom is a serene oasis for anyone looking to sleep through the night—sweat free. And yet, you’re still waking up reaching for a towel. 

In some cases, night sweats can also be a sign of health-related issues. 

Some of the more common health-related issues associated with night sweats and hot flashes are:9 

  • Menopause 
  • Infection 
  • Sleep apnea
  • Anxiety 
  • Cancer 
  • Acid reflux 
  • Hyperthyroidism
  • Obesity 
  • Low blood sugar 

When it comes to maintaining a healthy body and lifestyle, it’s easy to forget how important it really is to get quality sleep every night. In fact, over 60% of Americans report having trouble sleeping a few nights a week, most of those with undiagnosed or underlying health issues to boot.10 

If you’ve tried it all and you’re still waking up wondering the same thing: “why do I sweat in my sleep?”, then don’t be afraid to touch base with your health professional. They’ll be able to help sort out any underlying cause or issues to  find a solution to avoid nighttime sweating.

Some sweatless slumber could be just a checkup away. 

Don’t Sweat It—Casper Has Got Your Back

Sweating through the night might feel like your new normal, but that doesn’t have to be the case. A few lifestyle changes or bedroom upgrades could be all that’is standing between you and a sweat-free night of sleep.

What’s more, Casper has an entire range of products dedicated to elevating your sleep and keeping you cool all night long. Whether you want to start with an upgrade to your bedding or  swap out that old sweat-stained bed for an innovative, cooling mattress, Casper has got you covered. 

And with a 100-day risk-free trial period, you can upgrade your entire sleep setup and see just what it feels like to sleep a bit cooler, and a bit less sweaty.  

We’ve dreamed up the perfect way to sleep. If you’re not completely satisfied, don’t sweat it— Casper will be there to help every step of the way. Now is the time to wipe off your brow, hang up your nightly towel, and get some sweat-free shut-eye.


  1. National Library of Medicine Prevalence of night sweats in primary care patients: an OKPRN and TAFP-Net collaborative study https://pubmed.ncbi.nlm.nih.gov/12019054/ 
  2. Harvard Health Publishing Top 4 reasons why you’re not sleeping through the night https://www.health.harvard.edu/staying-healthy/top-4-reasons-why-youre-not-sleeping-through-the-night
  3. National Library of Medicine Prevalence of night sweats in primary care patients: an OKPRN and TAFP-Net collaborative study https://pubmed.ncbi.nlm.nih.gov/12019054/ 
  4.  National Library of Medicine Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices – Adverse Sleep Properties and Preventative Strategies https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4602096/
  5. Sleep Foundation Anxiety and Sleep https://www.sleepfoundation.org/mental-health/anxiety-and-sleep
  6. National Library of Medicine Effects of thermal environment on sleep and circadian rhythm https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427038/
  7. Casper What is the Best Humidity for Sleep? https://casper.com/blog/best-humidity-for-sleep/
  8. Casper Gel Foam vs. Memory Foam: The Detail That Makes a Difference https://casper.com/blog/gel-foam-vs-memory-foam/
  9. Sleep Foundation Why Am I Shivering or Sweating at Night? https://www.sleepfoundation.org/bedroom-environment/why-am-i-shivering-or-sweating-at-night
  10. American Psychological Association Why is sleep important. https://www.apa.org/topics/sleep/why
  11. Houston Methodist Leading Medicine Night Sweats: 7 Reasons You May Be Sweating at Night https://www.houstonmethodist.org/blog/articles/2020/feb/night-sweats-7-reasons-you-may-be-sweating-at-night/
  12. Mayo Clininc. Conditions that can cause night sweats https://www.mayoclinic.org/symptoms/night-sweats/basics/causes/sym-20050768