Are you constantly running a fan at night or often find yourself browsing the internet for the latest cooling bedding products? Struggling to sleep when you’re too warm — or not warm enough — isn’t uncommon; many people can experience this, either often or from time to time.
But have you ever wondered why this happens?
How the body regulates temperature at night can have a significant impact on your quality of sleep. We’ll cover what the science says about body temperature and sleep, along with tips to help you keep comfortable, whether you run hot or cold.
What Is Thermoregulation?
Thermoregulation is the process in which your body maintains its core temperature1. It’s your body’s way of balancing heat generated with heat lost.
For example, when your body becomes too hot, it produces sweat to help cool the skin. Shivering, on the other hand, helps your body warm up when it’s cold.1
On average, a healthy person will have a core temperature of 98.6 degrees Fahrenheit (37 degrees Celsius), plus or minus 0.9 degrees. This is the ideal temperature range for making sure the body’s metabolic processes function correctly.1
The human body’s ‘thermostat’ is located in the hypothalamus, an area of the brain that produces hormones. Essentially, the hypothalamus contains “temperature sensors” — also called thermoreceptors — that receive information from nerve cells called thermoreceptors. These nerve cells signal if you are too hot or too cold.1
How Body Temperature/Thermoregulation Affect Sleep
If you’ve ever laid awake shivering because you’re too cold or tossing and turning because you’re too hot, you can thank thermoregulation for that. These are potential signs that your body needs more or less heat.
Aside from helping you be comfortable for sleep, thermoregulation plays an important role in your sleep quality and duration.
According to sleep expert Chelsey Borson, “Our core temperature naturally drops as we prepare to sleep, signaling to the body that it’s time to rest.” Borson adds that “Disruptions in this natural cycle can lead to difficulty falling and staying asleep.”
In preparation for bed, we may lie in certain postures like curling up to promote thermal efficiency2 — or the ideal body temperature. Thermoregulating habits in humans also include nest-building, which takes on the form of “building a nest” with blankets and sheets to stay warm.2
Your skin warmth helps bring on NREM sleep, an active state of sleep that is followed by deep sleep. This also helps your body be able to cool down for resting.2
Typically, the lowest body temperature occurs around 4:00 a.m., which is when people often experience their deepest sleep.1
Factors that Impact Your Temperature During Sleep
As mentioned above, disruptions to the body’s core temperature can impact sleep. These disruptions can be caused by factors both in and out of our control. Here are a few potential triggers for temperature changes in the body:
- Fevers: Fevers3 are spikes in body temperature that can result from a variety of reasons, like viral or bacterial infections, sunburn, and reactions to a medication or recent vaccination. You may find yourself alternating between sweating and shivering at night with a fever. A fever is generally considered anything above 100.4 degrees Fahrenheit, but low-grade fevers are anything 99.1 degrees and above.
- Alcohol use: While you may feel warm and toasty after an alcoholic drink, the sensation likely won’t last for long since alcohol decreases body temperature4.
- Exercise: Exercise usually causes your body temperature to rise5, which is why your body sweats to cool itself down.
- Sleep environment: A bedroom that’s too hot or too cold can make it difficult to both fall and stay asleep. You may want to consider investing in fans and/or space heaters to create the ideal sleep environment, which is typically between 65 and 68 degrees Fahrenheit for most adults6.
Tips for Regulating Your Body Temperature at Night
While some factors that influence core body temperature may be out of your control, there are steps you can take to help regulate your body temperature at night.
Hot Sleepers
- Use breathable cotton bedding
- Invest in a cooling mattress
- Turn on overhead or floor fans
- Set your thermostat between 65 to 68 degrees Fahrenheit
Cold Sleepers
- Use flannel sheets or a weighted blanket
- Wear warm pajamas or sleep in layers
- Increase the room temperature
- Invest in a space heater
- Use a hot water bottle to warm your bed. Just remember to remove it before you get into bed.
Sometimes, a disorder known as thermoregulatory dysfunction can disrupt sleep and the ability to maintain a proper core body temperature.1
“Symptoms of thermoregulatory dysfunction include excessive sweating, frequent awakenings, and chills,” Borson says. “If these symptoms persist and disrupt sleep regularly, it’s crucial to consult a healthcare provider to explore potential underlying conditions.”
Frequently Asked Questions
Why does my body overheat at night?
Your body may overheat at night due to multiple factors, which can include a fever, alcohol use, exercise, and your sleep environment. If you keep overheating at night, talk to your healthcare provider.
What are the symptoms of thermoregulatory dysfunction?
Symptoms of thermoregulatory dysfunction include excessive sweating, frequent awakenings, and chills.1
Ashley Zlatopolsky
Content Writer
About Author
Ashley Zlatopolsky is a Detroit-based writer and editor who specializes in sleep content. She writes about sleep health, hygiene and products for Sleep Advisor, Mattress Clarity, Real Simple, Sleep.com and more.
Side Sleeper
References:
- Osilla, Eva, et al. “Physiology, temperature regulation”. StatPearls. Last modified July 30, 2023.
- Harding, Edward C., Franks, Nicholas P., Wisden, William. “Sleep and thermoregulation”. Current Opinion in Physiology. 2020.
- Balli, Swetha., Shunway, Karlie R., Sharan, Shweta. “Physiology, Fever”. StatPearls. Last modified September 4, 2023.
- Duong, Hieu., Patel, Gaurav. “Hypothermia”. StatPearls. Last modified January 19, 2024.
- Matsumura, Koichiro., et al. “Effect of Exercise Training on Body Temperature in the Elderly: A Retrospective Cohort Study”. Geriatrics. 2021.
- Caruso PhD, Claire C., Chosewood MD, L. Casey. “Improve Sleep: Tips to Improve Your Sleep When Times Are Tough”. Centers for Disease Control and Prevention. Last modified September 22, 2020.