How Sleeping In A Cold Room Actually Impacts Sleep Quality

According to Mental Health UK, 1 in 5 of us aren’t getting enough sleep. With this in mind, is it any surprise that we are always looking for tips and tricks to get better sleep wherever possible?

One common tip cited is that sleeping in a cold room can improve sleep quality and according to Dr Ritz Birah, Psychologist and Sleep Expert for Panda London, there may actually be some truth to this.

Dr Birah says: “I am frequently asked whether the temperature of our sleeping environment really affects how well we sleep.

“There is increasing evidence that sleeping in a cooler room can, in fact, improve sleep quality, but it’s not just about turning off the heating and braving the cold. Understanding the science behind this can help us optimise our sleep environment in a safe and effective way.”

So, does a colder room make for a better sleep?

Why temperature matters for sleep

Dr Birah says: “Human sleep is intimately connected to our circadian rhythm, the internal body clock that regulates when we feel alert and when we feel sleepy. A key part of this process is thermoregulation, the body’s natural regulation of core temperature.

“Normally, our core body temperature decreases slightly in the evening, reaching its lowest point in the early hours of the morning. This drop in temperature signals to the brain that it is time to sleep and helps initiate deeper stages of sleep, particularly slow-wave sleep, which is crucial for physical restoration and memory consolidation.”

This all makes sense so far, right? However, Dr Birah warns that when our sleeping environment is too warm, this natural drop in body temperature can be impaired.

“A bedroom that is hot or stuffy can make it harder to fall asleep, increase night-time awakenings, and reduce the amount of restorative deep sleep we experience.

“Conversely, a cooler environment supports the body’s natural cooling process, signalling that it is time to sleep and enabling deeper, more consolidated rest.”

What the research says

Several studies support the benefits of a cooler bedroom for sleep quality. Research published in Sleep Health and Physiology & Behavior indicates that the optimal bedroom temperature for most adults is around 16–19°C (60–67°F).

Dr Birah says: “Within this range, individuals generally fall asleep faster, experience longer periods of deep sleep, and report feeling more refreshed upon waking.

“Temperatures outside this range, particularly those that are too warm, have been associated with fragmented sleep and increased wakefulness during the night.”

He adds that experimental studies have also shown that a cooler environment may enhance sleep efficiency.

“For example, in one controlled study, participants who slept in rooms around 18°C experienced an increase in slow-wave sleep compared with those in warmer rooms.

“Slow-wave sleep is critical for physical repair, immune function, and cognitive performance, highlighting why temperature matters beyond mere comfort.”

How cold rooms improve sleep

“The benefits of a cooler bedroom go beyond just helping us fall asleep faster”, Dr Birah urges.

“The body’s thermoregulation interacts with the production of melatonin, the hormone responsible for promoting sleep. Cooler environments can enhance melatonin secretion, supporting a stronger circadian rhythm and helping maintain longer periods of deep sleep.

“Additionally, sleeping in a slightly cool room can prevent overheating during the night, which is a common trigger for restlessness or night-time awakenings.”

He adds that a cooler room, when paired with appropriate bedding, creates a comforting, cocoon-like environment that signals safety and restfulness.

“This combination of physiological and psychological cues contributes to a more restorative sleep experience.”

Practical ways to incorporate a cooler sleep environment

While turning the heating off is not something any of us are up for doing during cold winter months, Dr Birah advises that we can still make our sleeping environment cooler by doing the following steps:

Adjust bedding wisely

Use lighter duvets in winter, or layer bedding so that you can remove layers if you become too warm during the night. Breathable, natural fabrics like cotton, linen, or bamboo allow for better air circulation and heat regulation.

Thermoregulating mattress and pillow materials

Memory foam or latex mattresses that retain less heat, along with pillows designed for cooling, can help maintain a comfortable core temperature throughout the night.

Pre-sleep cooling routines

A lukewarm shower before bed may sound counterintuitive, but it helps slightly raise body temperature, which then drops rapidly after stepping out of the shower, naturally signalling sleepiness.

Ventilation and airflow

Keep a window slightly ajar or use a fan to circulate air. Even in winter, a small gap in the window can provide a cooler microclimate without making the room uncomfortably cold.

Use sleepwear strategically

Lightweight, breathable sleepwear can allow the body to cool naturally. Conversely, heavy or non-breathable clothing can trap heat, negating the benefits of a cooler room.

Avoid overheating before bed

Hot drinks, heavy exercise, or exposure to heated environments right before sleep can elevate core temperature. Allowing time for your body to cool down beforehand enhances sleep onset.

Sweet dreams!