How a Cold Shower Before Bed Affects Your Sleep

Cold showers are typically an unpleasant occurrence that happens when you run out of hot water. However, some people are now touting the benefits of a cold shower when it comes to sleeping better at night.

In this article, we’ll look at what the research says about how cold showers — and hot showers — affect your body and your ability to sleep.

How does a cold shower affect your body and sleep?
For hundreds of years, cold bathing has been a way to invigorate the body. Ancient RomansTrusted Source used to progress through several heated rooms before plunging into a cold bath. Today, most people simply turn the dial on their shower to get a cold blast.

There are a lot of reported benefits of cold bathing or showering on the body. These include:

enhancing immunity
enhancing overall feelings of vitality
improving blood circulation
However, there aren’t a lot of definitively researched benefits. We’ve included some below.

May make you feel more awake and alert
Researchers in an older 2002 study found that cold exposure activates the sympathetic nervous system. As a result, the body releases hormones such as norepinephrine and cortisol. Norepinephrine particularly triggers a reaction in the body’s blood vessels designed to redistribute the blood and warm the body.

Cortisol is another consideration. The body releases cortisol levels throughout the day that follow a fairly predictable pattern. Cortisol usually peaks at around 9 a.m. and decreases to its lowest point around midnight. Some studiesTrusted Source have connected increased cortisol levels at night with poorer sleep.

Do cold showers help you sleep?
Researchers haven’t looked specifically at whether cold showers can increase cortisol levels and affect sleep.

However, one study on cold exposure found that the body releases cortisol when exposed to the cold, while another found that increased levels of cortisol at night may lead to poor sleep. This could suggest that taking a cold shower before bed may be less beneficial for sleep.

Cold showers may be helpful for those who want to feel more awake or alert during the day.

May boost your immune system
To test the theory that cold showers boost the immune system, researchersTrusted Source randomized more than 3,000 participants to four trial groups: one group took hot showers only, while three groups took hot showers and included a blast of cold water for 30, 60, or 90 seconds at the end of their shower.

At the study’s conclusion, the researchers measured factors like reported illness and sick days over 30 days. They found that those who included any blast of cold water during their shower had a 29 percent reduction in sick days than those who took hot showers only.

Interestingly, the participants didn’t report that they were sick over fewer days, just that their symptoms weren’t as intense, so they were able to work. The researchers theorized the cold water may have helped reduce the intensity of their perceived symptoms

Soothes sore muscles after exercise
Professional athletes have long used ice baths to soothe sore muscles after a game or race. While cold showers may enhance hormone levels in those who are sedentary and take a cold shower, they can have the opposite effect on those who exercise.

A 2015 studyTrusted Source looked at high-intensity cyclists exercising in warm temperatures. The researchers asked a control group to take a cold shower for 1 to 3 minutes. They asked another group to omit the shower.

The researchers found that those who took a cold shower after exercising were able to decrease their heart rate more quickly and felt more comfortable, compared with those who didn’t take a cold shower.

The researchers also measured cortisol levels in both groups, but didn’t find any key differences.

Potential downside: You may incur lingering cold sensations
There aren’t many known downsides to cold showers. In a 2016 studyTrusted Source that examined the effects of cold showers, about 13 percent of participants reported a persistent sensation of cold in their body, including their feet and hands. The researchers didn’t note any other side effects.

How does a hot shower affect your body and sleep?
Fortunately, there are a few more studies on hot showers before bed and sleep. Some of the results are below.

Improves sleep quality
A 2019 systematic review found that taking a warm shower or bath (104 to 108°F, or 40 to 42°C) for at least 10 minutes 1 to 2 hours before bedtime improved the participants’ sleep quality more than those who didn’t take one.

Lowers blood pressure at bedtime
A 2019 study found that soaking in a warm bath for 11 to 15 minutes before going to sleep helped older participants lower their blood pressure before bed. Some participants’ blood pressures dipped as much as 16 mm Hg after a warm bath.

Helps you fall asleep faster
A recent study looked at more than 1,000 older adults with an average age of 72 who took a hot bath before bedtime.

The researchers found that those who took a hot bath before bedtime reported falling asleep quicker than those who didn’t take a hot bath before bed.

Potential downside: It may dry or irritate your skin
Like cold showers, there aren’t a lot of harmful side effects related to hot showers, providing the shower water isn’t too hot and you limit your shower time to around 10 minutes. Otherwise, the water could dry and irritate your skin.