Hot vs cold showers before bed: Which is best for a good night’s sleep?

Keeping clean and getting into a zen mindset are just two of many good reasons to shower before bedtime. But did you know the temperature of your bedtime bathing session can impact how well you sleep?

Our natural circadian rhythm relies on temperature cues to know when to wind down. Sleeping on a reliable, tried-and-tested cooling mattress is one way to help regulate your body temperature at night. However, a relaxing shower can also benefit your slumber.

But is a hot or cold shower before bed best for a good night’s sleep? We investigated the research and spoke to Dr. David Rosen, medical director at sleep apnea treatment company Complete Sleep, to see if there is a definitive answer.

Why does the temperature of your nighttime shower matter?

You may think the temperature of your nighttime shower should depend on personal preference. But there is a close relationship between temperature and sleep, and you can use the shower to help regulate your body temperature for improved slumber.

Your core body temperature must drop to facilitate the release of sleep-inducing hormones, which need to be present for you to fall and stay asleep at night.

“Temperature regulation is fundamental to healthy sleep architecture,” Dr. Rosen explains.

“Your core body temperature naturally drops by 1-2°F (0.5-1°C) in the evening as part of your circadian rhythm, triggered by melatonin release. This cooling process signals sleepiness and helps initiate sleep onset.”

Therefore, keeping your bedroom cool, sleeping with breathable bedding and lowering your temperature in the evening are crucial steps toward getting good quality shut-eye. Environments that are too hot can cause nighttime awakenings.

Hot vs cold shower before bed: Which is best for sleep?

There is research supporting both sides of the hot vs cold shower debate. Considering your body temperature must drop for you to sleep peacefully, you may think a cold one would be best.

But then, we’d probably all agree, there’s nothing more relaxing than being drenched in warm shower water. So, which way should you turn the temperature dial?

While one small study found that 12 athletes who immersed themselves completely in cold water for ten minutes after evening exercise experience a drop in core body temperature for 80 minutes after immersion, fewer nighttime awakenings and more deep sleep within the first three hours of snoozing, most research points to a warm pre-bed shower.

A review of 13 studies in 2019 concluded a warm bath or shower between 40 and 42.5 °C improved self-rated sleep quality and sleep efficiency, and that taking it one to two hours before bedtime, for even 10 minutes, shortened sleep onset latency.

Overall, there appears to be more evidence that a warm rather than cold shower is best for sleep.

Even though your body temperature rises while you’re in the shower, as soon as you get out, your core temperature will drop rapidly. This temperature decline can help initiate the production of sleep hormones.

Time your evening shower for better sleep

Dr. Rosen agrees that a warm shower is better for sleep optimization. But he warns timing your warm shower in the evening is crucial to resting well.

“A warm shower taken 1-2 hours before bedtime triggers vasodilation (blood vessel expansion) in your extremities, which helps dissipate core body heat more efficiently afterward,” he says. “This enhances your natural temperature drop.”

However, he adds, taking a hot shower immediately before bed can temporarily raise core temperature and delay sleep onset. So, be sure to take at least an hour to relax between your shower and hitting the hay.

Other ways showering before bed helps you sleep

Regardless of temperature, showering before bed has many benefits, from relaxing the mind to improving sleep hygiene…

Completes your bedtime routine

A key component to falling asleep fast and sleeping well through the night is a well-established nighttime routine.

You may assume this is something you don’t need after pre-school, but a bedtime routine can help you sleep whatever your age.

Think of your body like a machine that needs a little fine-tuning. A nighttime routine helps it recognise it is time to wind down to sleep.

As a catalyst for cooling down your body and activity that helps you relax, a warm shower is a no-brainer when you’re deciding what to include in this routine.

Improves sleep hygiene

Showering before bed helps maintain a clean sleep environment, which is crucial for restorative, healthy sleep. It’s important to wash away any allergens and oils built up on your skin during the day before getting into bed to stop them from irritating you through the night and disturbing your sleep.

“Showering removes the day’s accumulation of sweat, oils, and environmental pollutants, which can improve comfort and skin health during sleep,” Dr. Rosen says.

Allergens and body oils can also build up in your mattress, causing stains and premature aging.

Even the best mattresses can’t wash themselves, so you should be conscious of taking these residues into bed if you want your mattress to remain comfortable and supportive for the duration of its lifespan.

Stress reduction

Showering often has a calming effect on the brain and body. Warm water can helps release tension in muscles, and can reduce cortisol, which is likely to result in you feeling calmer before bed.

Another bonus for warm water, Dr. Rosen points out, is that it activates the parasympathetic nervous system, the processes of which including lowering heart rate, which puts our body in a state of ‘rest and digest’ calmness (cold water, meanwhile, activates the sympathetic nervous system, our ‘fight or flight’ response).

Showering also provides time to reflect on the day and to compartmentalise worries before going to bed, which can help prevent nighttime anxiety sabotaging your rest.