If you've ever noticed yourself having trouble sleeping in the summer, or if you've woken up with your feet freezing cold one winter night, or if you've had trouble falling asleep after a particularly late (in time) evening meal, then you've experienced firsthand why temperature affects your sleep.

Both the temperature of your sleeping environment and your body temperature directly affect how well you sleep. However, we often don't connect how well we sleep to how warm or cold our bed and bedroom are.

In this article, we will gather everything you need to know about how temperature affects your sleep and what you can do to create the most ideal environment for quality and restful sleep.

We'll explain why your body temperature is key to sleep and how many things can alter your temperature and affect how you sleep at night. We'll also give you lots of tips on how to influence your body temperature to instantly improve your sleep.

By learning more about how these changes affect our sleep - and how our sleep affects them - we can more easily adjust our environment and routines. This can lead to more efficient, deeper and more comfortable sleep and, as a result, multiple health benefits .

So let's start by taking a look at what happens to your body temperature during the day and night and how it relates to your sleep.

Body temperature changes during the day

Normal body temperature is around 37°C, but it can vary slightly depending on age, physical activity levels, food intake and time of day. Your temperature varies by up to 1°C throughout the day.

Your core body temperature follows a circadian rhythm, meaning it rises and falls over a 24-hour cycle. At the beginning of the day, your body temperature is low and rises steadily throughout the day. As evening approaches, it begins to drop again.

The drop in core body temperature is thought to be a signal for our bodies to prepare for sleep - this is something that is common to all mammals, from mice to humans.

In preparation for sleep, body temperature begins to drop and this is associated with a reduction in the time it takes to fall asleep . During the night, our body temperature continues to drop until it reaches its lowest point in the early morning hours, around 2 to 4 am.

It has been shown that an increase in core body temperature during sleep triggers arousal . About two hours before you wake up, your core body temperature begins to rise and continues to rise throughout the day, peaking in the early evening.

Additionally, it has been shown that people who suffer from chronic insomnia have a rise and fall in their core body temperature that is out of sync with their normal rhythms. Their core body temperature does not fall in line with their chosen bedtime, making it difficult for them to fall asleep.

For core temperature changes to occur, our body must be able to retain or lose heat effectively.

This is done through the skin, which has a network of blood vessels extending beneath it. The blood vessels open up (this process is called vasodilation) or narrow (vasoconstriction) depending on whether the body's core temperature needs to be lowered or raised.

If the body's core temperature needs to be lowered, heat can be lost through the distal skin (the skin furthest from the core, including the hands and feet) . In this way, the skin acts as a "heat sink" that radiates heat and effectively cools the body.

So when your body needs to lose heat, the blood vessels will dilate, most noticeably in your hands and feet, and heat will be lost. Your hands and feet will feel warm as they dissipate this heat.

Our bodies are very efficient at generating their own heat, so if the temperature needs to rise, blood vessels throughout the body will constrict to minimize heat loss through the skin.

This system works hard 24 hours a day and constantly adjusts to maintain our body's core temperature around 37°C.

Body temperature and melatonin

We know that heat loss through the hands and feet helps us fall asleep quickly , and that this heat loss is associated with an increase in the key sleep-promoting hormone, melatonin.

Melatonin is important in many processes in the body and is thought to be the master signal that activates a sequence of other signals in the body to prepare us for sleep. The production of melatonin itself is largely controlled by exposure to sunlight.

The first light that enters our eyes in the morning is the signal to stop melatonin production in the body. Levels of the hormone remain low for most of the day and then begin to rise as light levels drop in the late afternoon and evening.

There are several connections between melatonin and temperature regulation in the body, and we know that increasing it can reduce core body temperature and increase peripheral temperature .

As melatonin levels increase at night, so does heat loss from the hands and feet. On a more complex level, melatonin is involved in cell signaling that results in the opening of blood vessels to release heat.

Why is this important?

As we said earlier, melatonin is regulated by exposure to sunlight. Adequate exposure to sunlight each day is crucial to keeping melatonin production in sync with sleep/wake cycles.

Since melatonin and temperature are linked, taking care of one can benefit the other. So getting outside in natural light every day, especially in the morning, can help keep your melatonin in check, which can affect temperature regulation.

Why can body temperature affect sleep?

We've already said that changes in body temperature help us fall asleep, but they also affect how well you sleep. A higher core body temperature in bed can affect how deep sleep you enjoy.

Sleep consists of two types of sleep: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. We cycle through NREM and REM several times during the night.

When you fall asleep, you enter the first stage of NREM sleep, called stage 1. This is a very light sleep. Then you move into stage 2 sleep, which is deeper than stage 1 but still quite light sleep. After that, you enter stage 3 sleep, the final and deepest stage of NREM sleep. Stage 3 is followed by REM sleep, which is also a deep sleep.

At this point you may be wondering why we're giving you a tour of the stages of sleep. It turns out that changes in temperature can affect these stages of sleep and, as a result, how well you sleep.

Interestingly, there are slight changes in your body temperature as you cycle between REM and non-REM (NREM) sleep . Your body cools down when you enter NREM and warms up slightly when you enter REM.

We also know that higher body temperatures during sleep are associated with a lower amount of deep sleep, both stage 3 NREM and REM sleep, and this can have a noticeable effect on how you feel when you wake up.

Deep sleep is important for restoring and repairing your muscles and tissues. If you've ever fallen asleep with aches and pains after a particularly tiring day, deep sleep is what helps you feel physically refreshed the next morning.

Deep sleep is also the time when your brain processes everything you experienced during the day and turns it into memories . This means that if you get too hot at night, chances are that your deep sleep is not satisfactory.

That is, you may wake up and not feel refreshed or your head may feel foggy, but you may not necessarily associate it with the fact that your bed was too warm.

So, having analyzed how body temperature affects your sleep, let's examine how ambient temperature can also affect your sleep.

What is the ideal room temperature for sleeping?

For sleep, the ideal bedroom temperature ranges between 15.5-21°C . A good average often cited in the literature is to aim for a bedroom temperature around 18.3°C.

If your room is too hot or too cold, it can have a negative impact on your sleep. Most of us have slightly different preferences for the temperature we feel comfortable in, so you may need to try several options to find the temperature that works best for you.

You should also keep in mind that your bed will affect how warm or cold it is in the evenings. While the temperature in your room should be on the cooler side of the thermometer, the temperature in your bedding should be on the warmer side.

This creates a temperature gradient in which your body remains warm under the covers, but the cooler temperature of the bedroom allows for effective heat loss from your head and exposed arms and legs.

The temperature under your bed sheets should be between approximately 27 and 31°C to ensure good sleep .

When the temperature in your bed drops below 26°C, you may find yourself waking up during the night. Temperatures above around 32°C can also disrupt your sleep, particularly affecting how deep your sleep is .

Air humidity is also important. High humidity levels, especially in warm climates, can reduce deep sleep and increase wakefulness during the night .

It's also worth noting that your temperature preference is also influenced by factors like the time of year and your gender. We can tolerate higher sleeping temperatures during the summer than in the winter, and women prefer a slightly warmer bed temperature than men .

It may be helpful to experiment with different pre-bedtime activities, such as bedding and clothing fabrics, as well as room humidity levels, to determine what works best for you.

For example, if you often get hot in your sleep, our Ice bamboo sheets are an ideal choice, because the fabric we use has the property of being 3 °C cooler than cotton and at the same time being constantly ventilated so as to keep you cool all night long.

Since we're all different, the ideal sleeping temperature is a personal thing. If you find yourself waking up in the night, take a moment to think about whether you feel too hot or too cold. Let's now look at how to improve your sleeping temperature.

How to achieve the perfect temperature for sleeping?

We mentioned earlier that a prerequisite for falling asleep is for your core body temperature to drop slightly. You can actually use this fact to help yourself fall asleep more easily.

But how?

The answer may surprise you. It's not by exposing yourself to the cold, but by warming your skin before you go to sleep. Warming the peripheral skin causes blood vessels to dilate, so more heat escapes through their walls and we lose body heat more quickly.

So, when you fall asleep, you are already in the process of cooling down.

You can help speed up this process by cooling your body's core in the following ways:

• taking a warm bath, shower, or just a foot bath
• mild exercise a few hours before bedtime.

Let's explore these in a little more detail.

1. The effect of a hot bath

Taking a warm bath before bed is a scientifically proven way to help us fall asleep more easily. In fact, it's referred to in the scientific literature as the "warm bath effect," and there's a lot of data to support it.

Spending just ten minutes under warm water an hour or two before bed has been shown to reduce the time it takes to fall asleep, increase the duration of your initial sleep, and also increase your deep sleep .

We probably all know that feeling of getting into bed and snuggling under the covers. This warms the space between your body and the duvet and the blood vessels dilate, allowing the body to lose heat.

This is exactly what happens when you take a bath before bed. You simply start the process before you get into bed, so by the time you fall asleep, the heat loss has already begun.

2. Exercise before bed

Studies have shown that exercising up to two hours before bedtime can reduce the time it takes to fall asleep and may increase the amount of deep sleep you achieve.

When you exercise, your body temperature rises and then, once you're done, it naturally cools down. This effect is similar to what happens after a hot bath. Exercise also increases your sleepiness, helping you feel more tired at bedtime.

Exercise can also help you de-stress and reduce stress, making it easier to get a good night's sleep. So, there are multiple benefits to getting some exercise in the hours before bed.

However, it's best to avoid exercising too close to bedtime, as it's not a good idea to go to bed when you're still hot from exercising, as this will make it harder to fall asleep. The intensity of your exercise can also affect how well you sleep.

A recent analysis of 15 studies on high-intensity exercise before bed found that as long as the exercise was no less than two hours before bedtime, there were no negative effects on sleep.

With anything less than two hours, not only do you risk muscle soreness, but you may experience a decrease in the amount of refreshing deep REM sleep .

3. Choose your bedding carefully

Bedding plays a big role in how warm or cold you feel in bed, so it's worth finding the right balance. If you find yourself waking up with the covers tossed to one side, you might want to consider a thinner duvet. If you're feeling cold, try switching to a duvet with a higher tog rating.

A good option is to choose the Gravity Ice gravity blanket , which is made of thermoregulating fabrics, allowing the body to reach the ideal temperature in winter or summer so that you don't get cold or hot respectively.

What else can affect your body temperature?

What you eat and drink, and how close to bedtime you choose to consume them, can affect your body temperature and significantly impact your sleep. Eating a large or fatty meal too close to bedtime is one such factor that can reduce how well you sleep.

After you eat, your body starts working to digest the food. Your metabolic rate increases, which means your body burns more calories, causing its temperature to rise slightly. Think of it like lighting a wood-fired oven - you put the fuel in, it ignites, and heat is released.

So, if you fuel your body too close to bedtime, or even if you eat a few hours before bed, but the meal was particularly large, high in fat or protein, then your body temperature will be slightly higher than normal.

As we know, your body temperature needs to drop for sleep to occur, so this increased temperature from eating won't help you sleep. This can also happen when you drink alcohol or caffeine in the evening, as both can raise your body temperature.

By knowing the factors that can negatively affect your body temperature and those that can help you lose heat before sleep, you can take steps to optimize your temperature before going to bed.

What should you take away from this article?

Temperature plays a huge role in your sleep, affecting everything from how quickly you fall asleep to how deeply you sleep. Understanding how body and environmental temperature can affect your sleep can help you create the right sleep habits.

• Your body temperature naturally drops in preparation for sleep, and this helps you fall asleep at night.
• Taking a bath or shower in the hours before bed can help your body temperature drop.
• Your bedroom temperature should be around 18.3°C for good sleep, but the specific temperature that works for you may be slightly lower or higher than that.
• If you wake up a lot at night from being too hot or too cold, then this will have an impact on your overall sleep, so it's worth changing your bedding to create the right sleeping temperature for you.
• Sleep disorders, such as insomnia, can be related to temperature regulation problems, so the tips in this article may help you improve symptoms.

Improve your sleep quality with a gravity blanket

Gravity blankets are the most effective way to deal with insomnia and stress without medication, as they have been used for many decades to help people suffering from anxiety disorders, autism, and other sensory disorders.

How do they work?

They are designed to apply gentle, steady pressure to the entire body, which occupational therapists call “ Deep Tactile Pressure .” This steady pressure relaxes the nervous system and helps the body naturally increase levels of serotonin and melatonin (the hormones of happiness and sleep) while reducing levels of cortisol, which is responsible for stress.

As a result, the mind stops "racing", the heart rate drops, the mood improves and the body enters a state of complete relaxation.

Choose the one that weighs closest to 10% of your body weight and upgrade your sleep from the very first night.

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