Sleep Too Hot Or Too Cold? Understanding Thermoregulation and Sleep

by | Last updated Mar 1, 2022

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Thermoregulation allows your body to maintain its core internal temperature. It’s one of your body’s most essential and important processes.  Many of your body’s critical day-to-day processes are controlled by enzymes and those enzymes are temperature sensitive. 

Thermoregulation ensures your body stays at the right temperature, preventing you from getting too hot or too cold. Whether you’re sweating in the summer heat or keeping warm in the dead of winter, your body’s thermoregulation process works to keep your body at its ideal temperature. 

Thermoregulation is also an important function for quality sleep, and sleeping at your ideal temperature is key to getting a good night’s sleep. 

If you tend to get overheated or too chilly while you sleep, sleeping soundly can be a real challenge. Discover the ideal temperatures for sleep, plus tips for if you get too hot or too cold. 

If these small easy changes to your bedroom temperature or environment don’t help, sleep disorders or health challenges may be to blame. We’ll share signs to look for that may be preventing you from getting comfortable sleep.

So how exactly does thermoregulation help you sleep? 

First, let’s take a closer look at thermoregulation, and how the process works in your body. If you feel like you already know how thermoregulation works, you can skip ahead to our section on how to sleep at your ideal body temperature.  

What is Thermoregulation?

Thermoregulation is the process that allows your body to maintain its core temperature and prevent thermal stress. Thermoregulation also keeps your brain temperature regulated, maintaining brain function.

All animals use thermoregulation in response to the ambient temperature around them. Warm-blooded animals including birds and mammals— and humans— have physiological ways to regulate their body temperatures

Cold-blooded animals— like reptiles, fish, and amphibians— however, rely on external factors like weather or protection from the elements to regulate their temperature. Because of this, warm-blooded animals maintain a higher body temperature than cold-blooded animals.

Your baseline core body temperature ranges between 98°F and 100°F. While your body temperature can vary a few degrees, any changes in core temperature beyond that can make it harder for your body to function. For example, your body temperature falling below 95°F can cause hypothermia, while body temperature exceeding 107°F can cause hyperthermia— both of which can lead to brain damage and even death.

Illness, fever, digestion, and exercise can raise your internal body temperature. Drug use and conditions like an under-functioning thyroid gland can lower your temperature. 

Obviously, environmental temperature is another key factor to your core body temperature. Heat will raise your temperature, while cold reduces it.

How Does Thermoregulation Work?

Thermoregulation is regulated by your brain’s posterior hypothalamus— when it detects changes in your body temperature, it sends signals throughout your body to help bring the temperature back to normal.

All animals have a number of thermoregulatory mechanisms to use to respond to heat stress or cold stress. Mammals’ bodies have a number of physiological ways to regulate their temperature. Beyond that, humans also have unique methods to help with temperature regulation. For example, while all mammals have sweat glands, very few perspire to cool down like humans do.

Here are a few of your body’s temperature regulation methods:

  • Sweating: We’re all familiar with this one. When you’re overheated, your sweat glands release perspiration or sweat, which helps to lower your skin temperature and reduce body heat as it evaporates. Be sure to stay hydrated if you’re sweating in the heat— too much water loss from sweating can lead to dehydration.
  • Shivering: This is another familiar sensation. When you’re cold, your muscles produce heat by making you shiver, which generates heat via those muscle contractions. Every person’s body has what’s known as a shivering threshold. This means that below a certain temperature, you have the potential to shiver— for humans, this is about 96°F, and any temperature below that.
  • Cutaneous vasoconstriction: If you’re cold, your blood vessels constrict and your skin blood flow reduces, which helps retain heat in your inner body.
  • Nonshivering thermogenesis: A means of heat production in your body’s brown adipose tissue— this type of fat helps maintain your body temperature when you get cold. Like the name says, temperature regulation doesn’t take place by the body shivering.

Like any of your body’s processes, thermoregulation can be hindered by health conditions or extreme temperatures, which can cause additional problems. In severe cases, impaired thermoregulation can lead to disorders or illnesses like hypothermia and hyperthermia as mentioned above, as well as heat stroke or anhidrosis, or the absence of sweating.

So with all this information about how thermoregulation works for your body, you’re probably wondering how it ties into your sleep. Let’s take a look at that now.

How Thermoregulation Impacts Your Sleep

Your body’s ability to keep itself warm or cool down can make a significant difference in your sleep quality. 

Getting ready for sleep itself is actually a thermoregulatory behavior. When your circadian rhythm prepares your body for sleep, your body temperature begins to cool down. In mammals, this encourages behavior like nest-building, seeking warmth, or curling up to compensate for the temperature drop— this is known as behavioral thermoregulation. Your body and brain temperature both cool down during non-rapid eye movement (or NREM) sleep, while transitioning to REM sleep will warm these temperatures, and you, right up.

So put simply, thermoregulation is vital to not only how well you sleep at night, but also how your body prepares itself for sleep. However, certain health conditions can impact your body’s ability to regulate its temperature.

Menopause

Menopause symptoms can affect individual women differently, but many of its best-known symptoms can cause sleep disturbances. One of the most well-known of these are hot flashes and night sweats.

Hot flashes are sudden feelings of intense heat, typically focused around a woman’s head, neck, and chest. Night sweats are hot flashes that occur during sleep. Most women experience these symptoms during menopause, and it’s not uncommon for a woman experiencing these to wake up during the night feeling overheated and sweaty. These symptoms are caused by fluctuating hormone levels, and can last for more than 7 years.

So what does thermoregulation have to do with it? Hot flashes are intense heat dissipation responses to small increases in core body temperature, which are caused by a woman’s changing hormone levels. While hormone treatments are highly effective in treating hot flashes during menopause, some easy lifestyle changes can also help you sleep better. (More on those later.)

You can also read our recent article about How Menopause Affects Your Sleep, including associated sleep disorders more common for women during menopause. 

Sleep Deprivation

Sleep deprivation can have some really surprising effects on your body. One of these potential effects is hormonal imbalances. Just like with menopause, hormonal imbalances brought on by sleep deprivation can raise your body temperature and lead to hot, uncomfortable nights.

Your hormones are controlled by interactions between your pituitary gland and your hypothalamus— this is the part of your brain that also regulates your body temperature. 

How your body responds to your environment depends on how well your hormones function, and how well your hormones function can depend on how well you sleep. 

This is why it’s so important to get tested if you think you may have a sleep disorder— your body depends on sleep to function, and operating on subpar sleep can cause a lot more problems than just feeling groggy during the day.

Related: How Sleep Affects Your Hormones

Obstructive Sleep Apnea (OSA)

Thermoregulation has a very interesting relationship with obstructive sleep apnea. Sleep apnea occurs when the airway is partially or completely obstructed during sleep, creating signature symptoms like loud snoring, gasping, or choking during sleep.

Sleep apnea symptoms contribute to sleep deprivation or insomnia, which have their own undesirable effects on your body’s temperature regulation, including the above-mentioned hormonal imbalances.

Interestingly, sleep apnea actually has a key detail in common with thermoregulation— mainly one of your body’s many ways to keep warm. Through a process known as reflex bronchoconstriction, the airways constrict in response to cold air so that the air can be warmed before it reaches your lower airways. Because it gets colder at night and your body temperature drops, sleep apnea could possibly be your body’s way of keeping your temperature regulated and preventing you from getting too chilly.

However, sleep apnea is a very serious condition with a lot of potential complications. If you think you or a loved one may have sleep apnea, it’s important to get tested as soon as possible.

Why Environmental Temperature Matters

As mentioned earlier your body will naturally cool off at night anticipating sleep, but environmental heat can disturb this balance between sleep and body temperature. 

Therefore, setting your thermostat to an ideal sleeping temperature and creating the right sleep environment with things like a cooling mattress topper, the right bedding, or even the right pajamas can make a big impact. 

This is especially true if your body naturally runs hot, you’re older, or have insomnia (studies show people with insomnia often have warmer core body temperatures before falling asleep). 

Best Temperature for Sleep

Experts agree the ideal sleeping temperature is between 60 and 67 degrees Fahrenheit. 

A cooler temperature room will not only help you lower your core body temperature for better deep sleep and help you stay asleep, but it will also help you initiate sleep. 

One reason a cooler bedroom temperature helps you fall asleep is because melatonin levels increase in cooler temperatures. 

Why is Your Bedroom Temperature Important for Thermoregulation?

At night, during REM sleep, your brain (your hypothalamus) stops regulating body temperature. During this time when your body’s innate ability to thermoregulate, or maintain your body temperature, is affected, the need for ideal external temperatures increases.  

Your thermal environment is also a key factor in regulating your sleep. With disrupted or disturbed sleep you’ll experience more daytime sleepiness or exhaustion, which impacts your entire quality of life. 

For most people, it’s an easy adjustment to make resulting in immediate sleep and health benefits. 

How to Sleep at Your Body’s Ideal Temperature

Whether you sleep hot or at night, there are steps you can take to ensure that you get the rest you need without your body working overtime to keep you comfortable. Check out some of our recommendations below.

If You Sleep Hot

Whether you are experiencing symptoms of menopause or having trouble sleeping in the summer heat, here are some easy ways to keep cool and sleep well.

  • Encourage airflow by keeping a door or window open, or use a fan to circulate cool air.
  • Avoid caffeine, alcohol, or large meals before bed— these can spike your body temperature. Alcohol can also worsen any snoring or sleep apnea symptoms.
  • Don’t exercise right before bed. This elevates your body temperature, and may keep you uncomfortably warm while you’re trying to rest.
  • Use the right bed sheets— moisture-wicking sheets are especially great if you sleep hot, have hot flashes or have night sweats. Similarly, you may also consider pillows, mattresses, or even pajamas with cooling technology. These can help keep you cool and dry even through the hottest nights.
  • Invest in sleep technologies that keep you cool at night such as Chilisleep products. The Chili Cool Mesh Mattress Pad allows you to program your perfect sleep temperature so you get into deep sleep easier and avoid waking up hot and tired— especially in hot summer months or experiencing night sweats.

If You Sleep Cold

It’s tough to get a good night’s sleep if you can’t keep yourself warm enough. Thankfully, it’s easy to make sure you stay comfortable and get the rest you need.

  • Make use of layers. Wear long pajamas made of warm, breathable fabric, and use as many blankets as you need. You can remove any layers as needed if you get too hot.
  • Keep your feet warm with socks or additional blankets. Same with your hands— our bodies cooling down can make our hands and feet cold, so keeping them nice and toasty will help you sleep more comfortably.
  • If you can, turn up the thermostat, but remember the ideal temperature is 60 and 67 degrees Fahrenheit, so if you need to increase the thermostat it should never be past 72°F. Seek medical advice if you suspect you’re sleeping cold due to thyroid disruption or some other condition and consider how your bedroom temperature may impact your sleeping partner (or even yourself if you get too warm later). Alternatively, you can use a personal space heater to warm up. Just make sure it’s not a fire hazard or a tripping hazard.
  • The same sleep technologies that allow you to sleep cool at night, can also be deployed for sleeping warmer when needed. With a sleep temperature scheduling system that can ensure you don’t wake up in the middle of the night too chilled.

When to Consult an Expert

Adjusting your temperature to the best temperature for sleep and making changes to your bedroom environment can make a huge difference in how comfortably you sleep. It will also help your body maintain a comfortable temperature at night during REM sleep when the brain stops regulating the body’s temperature. If there is an underlying issue to blame for your sleep disruption, especially if it’s impacting your body’s ability to properly thermoregulate, then extra steps are needed. 

If you think that a sleep disorder is to blame for your poor sleep, contact your sleep specialist. They can help you get diagnosed and get the treatment that’s right for you. If you’re in the Nashville Tennessee area you can contact Sleep Centers of Middle Tennessee today to get started!

Healthy thermoregulation is key to getting a good night’s sleep, so don’t ignore any disturbances that sleeping too hot or too cold can cause. 

References

Holland, Kimberly. “Thermoregulation | Definition and Patient Education.” Healthline, Healthline Media, 7 June 2017, www.healthline.com/health/thermoregulation. 

Wang, Huan, et al. “Thermal Regulation of the Brain-an Anatomical and Physiological Review for Clinical Neuroscientists.” Frontiers in Neuroscience, Frontiers Media S.A., 21 Jan. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4720747/. 

Akin, Jonathan A. “Homeostatic Processes for Thermoregulation.” The Nature Education Knowledge Project, Nature Publishing Group, www.nature.com/scitable/knowledge/library/homeostatic-processes-for-thermoregulation-23592046/. 

Harding, Edward C., et al. “The Temperature Dependence of Sleep.” Frontiers, Frontiers, 24 Apr. 2019, www.frontiersin.org/articles/10.3389/fnins.2019.00336/full. Reser, Jared Edward. “Sleep Apnea, Respiratory Cooling and Thermoregulation.” Medical Hypotheses, U.S. National Library of Medicine, 20 Aug. 2009, pubmed.ncbi.nlm.nih.gov/19699039/.

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