Dr. Kelvas says that the body has trouble controlling these hormones when the room is too hot or cold, which can make it hard to fall asleep or stay asleep.

The Sleep Foundation says that the ideal room temperature is between 60 °F (15.5 °C) and 68 °F (20 °C). It helps the body’s thermoregulatory system, which leads to healthy sleep latency (the time it takes to fall asleep) and good sleep in general.

Being warm and the body

This is because our bodies have a thermoregulatory system that keeps our internal temperatures healthy no matter what the temperature is outside. The body also controls temperature through a complex network of physiological responses, such as shivering, sweating, and changes in blood flow to the skin.

Sweating is one of the main ways that our bodies cool down. If your body temperature goes up, sweat glands make water that evaporates from the skin’s surface. This lets go of heat and cools the body.

On the other hand, shivering is the body’s way of making heat when it gets cold inside. As a reflex, shivering makes muscles contract quickly, which makes heat that raises the body’s temperature.

Vasodilation, or the widening and narrowing of blood vessels, can also change body temperature. For instance, when the body needs to cool down, blood vessels close to the skin’s surface open up and let more blood flow through them. This rise in blood flow helps the body get rid of heat. But when the body needs to keep heat in, blood vessels close to the skin’s surface narrow. This slows blood flow and keeps heat in.

As you get ready for bed and ease into the different stages of sleep, all of these things work together. You may have felt this change in temperature before. Putting on socks can help you feel a little warmer when you’re cold in bed, for example. This is because our hands and feet lose a lot of heat. Putting something over them will help you feel warmer. If, on the other hand, you feel warm under the covers but don’t want to fully kick off the blanket, sticking your feet out from under it might help you cool off enough to fall asleep.

Weather and sleep

Temperature has always been a good indicator of when to sleep and wake up for humans. It acts as a “zeitgeber,” which is a time-giving external cue that changes our circadian rhythm. Researchers who looked at sleep in three different pre-industrial societies found that people fell asleep just as the temperature outside started to drop and stayed asleep as it dropped. Also, waking up usually happened before sunrise, when it was the coolest outside and the temperature of the fingers showed that the blood vessels were getting smaller, which is called vasoconstriction.

Keeping your body at the right temperature also affects the different stages of sleep. Researchers have found that your body temperature starts to drop about two hours before you go to sleep and reaches its lowest point during slow-wave sleep. In addition, the temperature in the brain starts to drop a little at this point.

Our body temperature stays around 98.6 °F (37 °C), but it changes by about two degrees Fahrenheit at night.

During sleep, our metabolic output goes down, muscle tone goes down, and sympathetic tone goes down because of vasodilation, which lets heat escape from deeper in the body.Valerie Cacho, MD, is an integrative sleep doctor and an expert on women’s sleep.

Even though light is usually linked to melatonin, Dr. Cacho said that a cool room and a drop in body temperature can also help the body make more of this “sleep hormone.”

Studies have shown that being outside in temperatures that are too high can hurt both the rapid eye movement (REM) phase and slow-wave sleep (SWS). During REM sleep, when your brain is very active, you dream. On the other hand, SWS is linked to less brain activity but faster physiological recoveries. For example, human growth hormone is released, muscles recover, and harmful substances like beta-amyloid plaques are flushed out of the brain. Both are, however, very important for good mental and physical health.

Researchers looked at how 10 older men reacted to warmer bedrooms and how well they slept. They found that even mild heat exposure at night would raise the thermal load, lower REM sleep, make the men more awake, and cause them to sweat more throughout their bodies.

Also, researchers at the University of California, Los Angeles discovered that warm-blooded animals with higher body temperatures have less REM sleep than those with lower body temperatures.

Humidity is another thing that can affect how well you sleep. One study found that being in humid heat made people more awake and less likely to be in REM sleep or SWS. The drop in core body temperature was also slowed down by humidity.

Dr. Kelvas said that if your room is too cold, your body may have to work harder to stay warm, which can keep you from falling asleep more deeply.

Why sleeping in a cold room is good for you

It may not seem important that room temperature has a big effect on sleep, but many people who have lived through a summer heat wave can relate. Think about times when you didn’t have air conditioning and had to sleep with a cold towel on top of you or in the living room, where it was cooler? Or have you ever been sleepy when you woke up from having night sweats? Hormonal changes during menopause make women even more sensitive to temperature changes outside. Even a woman who rides a bike has a slight change in body temperature throughout the month. To be more specific, it has been seen to rise during ovulation.

But the right temperature in your bedroom does more than just help you wake up feeling better. Here are four reasons why a cool room is good for you that will make you want to turn down the heat tonight.

Better quality of sleep

When you sleep in a cold room, your body releases enough melatonin, which keeps the stress hormone cortisol from rising and waking you up. Making it possible for your body’s temperature to drop during the night has been shown to help you spend more time in REM and slow-wave deep sleep, which are two of the best sleep stages for healing. You won’t have to worry about night sweats waking you up and making it hard to sleep at night either.

Get to sleep faster

This is what your body needs to do in order to fall asleep. Setting up a way for your body to get rid of extra heat and support its natural circadian rhythm will help you fall asleep faster. A good rule of thumb is that you should be fine if your sleep latency is between 10 and 20 minutes. People who are insomniacs, for example, have trouble sleeping because their bodies have a higher core temperature. This keeps them awake as their bodies try to cool down. This could wake them up or keep them from sleeping.

Better control of weight

If you don’t sweat, how does sleeping in a cold room help you lose weight? “Good fat,” or “brown fat,” is a type of tissue that is very metabolically active. It gets activated when it’s cold. The white fat around your stomach will burn more if you have more brown fat. Researchers in Australia put men in a controlled sleep environment where the temperature of the rooms was changed. They discovered that after one month of sleeping in a cooler room at 66 °F (18.8 °C), the body’s healthy brown fat had almost doubled in size.

Less chance of getting sick

Insulin sensitivity goes up when brown fat levels rise, which can help keep you from getting type 2 diabetes and other metabolic diseases. The Australian study also found that people burned more calories during the day when they slept in the 66 °F (18.8 °C) room.

A cool room may also help keep you from getting Alzheimer’s by letting your body go through all the healing stages of sleep while you get the recommended seven to nine hours of sleep. According to a study published in the journal JAMA Neurology, both short and long sleep periods were linked to worse outcomes for older adults. These included “greater beta-amyloid plaque burden, greater depressive symptoms, higher body mass index, and cognitive decline,” which shows how important it is to get enough sleep.

What to do when there’s no thermostat

Unfortunately, if you don’t have air conditioning or heating in your home, there are still some things you can do in the evening to help your body cool down before bed and stay cool during the night.

In the evening, take a warm shower or bath.

It might not make sense to cool off in a warm bath or shower, but there is a reason for it. Researchers looked at 17 studies to see how passive body heating in water, like a shower or bath, would affect different sleep metrics and found a link. They looked at data on sleep onset latency, awakenings after sleep onset, total sleep time, sleep efficiency, slow-wave sleep, and how well people felt they slept.