It should surprise no one that sleep and temperature are related, just ask the nearly 70 million Americans who suffer from sleep issues. We’ve all been there: lying on top of your covers while sweating on hot summer nights, shivering while your partner takes all of the covers, unexpected night sweats. When your temperature feels off, your whole night (and next day), can be off too.
However, it’s not just the thermostat being off or sleeping next to someone who feels like a furnace that’s affecting your sleep. There’s actually an intimate physiological relationship between sleep and temperature, and understanding it can help you better learn how to find that just-right feeling for a great night of sleep.
1. During sleep, the body naturally increases skin temperature and lowers core temperature (and the opposite happens when you wake up).
A lot of people are surprised to hear this; however, physiologically, our core body temperature shifts throughout day, and gradually cools by evening time, around when we go to sleep.
For our core temperature to decrease, it releases heat to the outer perimeter of our body, in places like the hands and feet. So even if we physically feel warmer, the cause may have something to do with our body temperature actually decreasing.
So how can we use this?
A 2019 study suggests that taking a warm bath or hot shower one to two hours before bed can actually improve sleep. It seems counterintuitive, but by submerging in hot water, we end up bringing our blood to the surface and radiate out that heat in our hands and feet. Doing so reduces our core temperature, and induces tiredness and helps us fall asleep faster.
Think about it like a seesaw with core body temperature on one end, and peripheral body temperature on the other, when one goes down, the other goes up.
Plus, it’s a relaxing way to end your day, and we all know how much feeling chilled out (or really, warmed up) at the end of the day can help make the night better.
2. Temperature and sleep stages are related
Many are familiar with REM Sleep (Rapid Eye Movement). This cycle of sleep occurs when the muscles in the body relax and the brain becomes more active. REM sleep is deep, which explains why waking up in the middle of a dream can feel like you’re being pulled from a coma.
Despite increased brain activity, temperature-regulating cells in your brain actually turn off during REM sleep. This means that your body is going to change temperature depending on what the temperature of the room is.
You’re most likely to be woken up by thermal sensations during your REM cycle, so that means if your open window has a cold breeze blow through it, you might be more likely to wake up than if you were in a different phase of sleep.
So what should you do if you wake up during REM sleep? A good starting place, whether you’re aware of thermal discomfort or not, is to go back and find your sweet spot for sleeping temperature. That could mean shedding a layer or pulling back the comforter from your snoring husband. It could be just the thing you need to do to get right back to your dream.
3. Hot Flashes can upend you
There are probably some people reading this shouting “obviously!” into their monitor, but it bears repeating: menopausal women (or anyone experiencing hot flashes, for that matter) deal with sleep issues differently than the rest of the population.
While up to 75% of perimenopausal women experience hot flashes, the sleep issues that accompany them are not as widely studied as other sleep problems. There are some things that we do know though.
Two out of three nighttime hot flashes occur during Phase 1 of sleep, which is the first 5 to 10 minutes of the sleep cycle when your body is still somewhat in between a state of wakefulness and sleep. So it’s more likely that you’re going to be awoken by hot flashes early in the night than later.
In fact, there tends to be fairly low incidences of hot flashes during REM sleep. Hot flashes dissipate heat throughout the body, so because the thermoregulatory part of our brains is mostly turned off during REM sleep, it would make sense that flashes aren’t triggered during this deep sleep. So while hot flashes can be disruptive, they’re likely not going to wake you up from a dream.
The ways that you can manage hot flashes during sleep are quite similar to the ways that one might manage hot flashes any other time of the day — anything as simple as exposing yourself to cooling sensations, or using Hormone Replacement Therapy (HRT should only be used after talking with your doctor.)
At Embr Labs we know how immediate cooling sensations can help ease the severity and duration of a hot flash. If you don’t have an Embr Wave, consider going to the bathroom and running your wrist under cold water, or putting an ice pack on your wrist. That quick cooling sensation can actually do a lot to move your overall comfort!
That being said, you can do things to better manage hot flashes that cause sleep disturbances. Make sure to sleep with your room at a cooler temperature, and use breathable fabrics like cotton. Having a fan next to your bed can help too.
4. Stress is a thermal wellness issue
Feeling too hot or too cold isn’t the only reason that we can’t sleep. Stress, or racing thoughts, can have a huge impact on our ability to get the rest that we need.
Stressful thoughts can induce the “flight or fight” response in our brain, which gives our body a sense of growing danger. While helpful in emergency situations, the “flight or fight” response isn’t exactly what we need when we’re trying to make sure that we’re ready for our 9am meeting the next morning.
This is where the Embr Wave comes in. The Wave’s temperature stimulation impacts the insular cortex in your brain. That part of the brain is crucial to dampening down and balancing the “fight or flight” responses and encourages the parasympathetic "rest and digest" response, which makes you feel calmer.
In simple terms: temperature can help you feel more relaxed, and feeling more relaxed can help you sleep.
Sleep can be a huge determining factor on your mood, physical and mental health, and overall well-being. The more that we’re able to understand it, the better we can create environments to make sleep successful for each of us.
At Embr Labs, we’re committed to improving the sleep of our customers and the world by being the leaders in temperature-related sleep solutions. To learn more about how Embr Wave can help your nights to improve your days, check out https://embrlabs.com/pages/research.