Hot or cold shower? Researchers compare which ensures better sleep

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

Let’s take a look at what the research says about how cold showers, and hot showers, affect your body and your ability to sleep.

Impact of a cold shower on our body

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For hundreds of years, cold bathing has been a way to invigorate the body. Ancient Romans 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:

Feeling more awake and alert

In an earlier study, researchers 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.

Improved immunity

To test the theory that cold showers boost the immune system, researchers 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.

Soothing for muscles

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.

The effect of a hot shower on your sleep and body

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Coming to the impact of hot showers there has been numerous studies conducted in this area and here are a few findings:

Better 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.

Lower blood pressure

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.

Fall asleep quicker

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.

So, which is better?

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The available research on the effects of hot or cold showers on sleep shows that people have a variety of responses to water temperature. This makes hot or cold showers before bed, and whether they can improve your sleep, seem more like a matter of personal preference.

Generally speaking, there’s more data to support that hot showers help improve sleep. This is likely because warm showers are thought to be relaxing, while cold showers are thought to be stimulating.

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