July 31, 2024

Why Body Temperature Matters for Adult Sleep

Adults

It was 90 degrees in Virginia the other night…at 10 PM! Growing up a Texas girl, heat used to be par for the course so I know some of you deep Southerners will raise an eyebrow at this being a big deal, but now that I’ve adjusted to life as a resident of Virginia, the past couple weeks have felt uncharacteristically HOT!

With record-breaking temperatures popping up around the country this summer, it seemed like an appropriate time to talk about how temperature relates to sleep.

You may readily agree with the statement, “It’s easier to sleep in a cold room than a hot one,” and you may have your nightly room thermostat set lower than during the day, but do you know why?

How Temperature and Sleep Work Together

Let me start with a crash course on circadian rhythm. You probably know the term, but you may not know that at its simplest, the circadian rhythm is essentially the cycling relationship between two hormones, cortisol (our alert hormone) and melatonin (our sleepy hormone).

In an ideal world, cortisol will be high in the morning, drop throughout the day, and be low at night when it’s time to go to bed. In parallel, melatonin should be low during the day and rise at night. This makes sense both logically and experientially! Absent any disruptive factors, we expect to be most alert during the day and get sleepy when evening and bedtime approaches.

Interestingly, another bodily function rises and falls throughout the day in concert with these hormones – our body temperature. Temperature is one of the two factors that generally governs your circadian rhythm, with light being the other one.

Your temperature is higher during the day then drops (or should drop) at night, and your body actually looks for this drop in temperature as a cue to produce melatonin and facilitate sleep onset. Then as morning approaches, your body temperature naturally begins to rise, suppressing melatonin production and allowing cortisol production to rise again so you can wake up ready for the day.

A key takeaway here is the principle that for restful sleep to happen, your core body temperature must drop 2-3 degrees leading up to bedtime.

In an ideal world, your body is wonderfully designed to do this naturally. But as we all know, things aren’t always ideal when it comes to bodily function and sleep. Different factors can keep your core temperature too high before bed or cause it to rise too fast at night, resulting in unwelcome disruptions to your sleep.

So, if you’re one of about 57% of Americans who find their sleep sometimes disturbed by the heat, whether because of the summertime temperatures or another factor, there are options to keep yourself cool throughout the night!

Tips to Help “Hot Sleepers” Cool Down at Night

Here are some best practices that you can employ before you go to sleep to beat the heat:

  • Turn your thermostat down! The ideal temperature for adult sleep is 60-68 degrees Fahrenheit, so turn the thermostat down a few hours before bed. 
  • Stop exercising at least ninety minutes before bed to give your body time to cool down.
  • Stay hydrated!
  • Use fans. For standing fans, try putting a bowl of ice cubes behind it to circulate even colder air. For overhead fans, make sure the blades spin counterclockwise to circulate cool air!
  • Skip the nightcap! While alcohol doesn’t actually change your core body temperature, it sends messages to your brain that you’re warm, which can throw off sleep!
  • Find your furry friends a new bed – they are heaters!
  • Take a hot shower or bath 1-2 hours before bed. This is one of those “counterintuitive” sleep principles. In the short term, the warmer water might heat you up while you’re in it, but the wonder of how our cardiovascular system works means in the long run, it allows our body to radiate heat out through our skin so our core body temperature can drop more quickly.

Tips for Staying Cool with Kids or Other “Cold Sleepers” in the House

Perhaps you’ve gotten this far and think, “That’s great, but my wife would freeze to death,” or, but the ideal temperature for my kids’ rooms is 68-72 Fahrenheit!

Part of the difficulty with getting the temperature right when you sleep is sharing your living space with someone who has a different preference or need. While my current living situation is such that I have complete control of the thermostat, I used to rent the basement from some friends in a three-story townhouse.

They were not only hot sleepers, but they also slept on the third floor (and heat rises!) so they tried to offset the heat with the thermostat. Therefore my basement room was FREEZING! I actually ran a space heater year-round to stay warm while they were often sweltering on the top floor.

If you’re in a similar situation, here are some personalized adjustments to try:

  • Invest in breathable bedding and pajamas (wool is really great temperature regulator!).
  • Try sleeping with an ice pack or frozen water bottle at night.

Conclusion

Sleep is complicated. And if you’ve been struggling with sleep for any length of time, this may seem oversimplified. Could turning your thermostat down and taking a warm bath before bed actually help you sleep better?

It absolutely could!

AND it might not be the only trick or tool needed to help you get a better night’s sleep. There are other tips and tricks to try both during the day and night to help you not only fall asleep well at night but stay asleep all night long.

For this reason, I created a free guide all about the Best Bedtime Routine for Adults, which includes a sleep environment checklist. It will teach you all about sleep hygiene and how to build a bedtime routine that will help your mind and body prepare for sleep – cooling down is just one tiny piece of that puzzle! So make sure you snag it!

If you find these suggestions helpful, but not a full solution to your problems, reach out! I’d love to set up a (free) discovery call to hear more about where you are on your sleep journey and to find ways I can help you not only stay cool, but also comfortable and sleeping well at night.

With Grace,

Kathryn, Your Adult Sleep Coach

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