Cooler bedroom temperatures help the heart recover during sleep:
Maintaining a bedroom temperature of 24°C [75°F] at night while sleeping reduces stress responses in older adults, according to new Griffith University research.
Dr Fergus O'Connor from Griffith's School of Allied Health, Sport and Social Work assessed the effect of increasing nighttime bedroom temperatures on heart rate and stress responses in older adults.
"For individuals aged 65 years and over, maintaining overnight bedroom temperatures at 24°C reduced the likelihood of experiencing heightened stress responses during sleep," Dr O'Connor said.
"When the human body is exposed to heat, its normal physiological response is to increase the heart rate.
"The heart is working harder to try and circulate blood to the skin surface for cooling.
"However, when the heart works harder and for longer, it creates stress and limits our capacity to recover from the previous day's heat exposure."
Study participants wore fitness activity trackers on their non-dominant wrist, and the bedroom temperature was monitored via installed temperature sensors throughout the Australian summer-long data collection period.
The data from the study provided the first real-world evidence of the effect of increasing bedroom temperature had on heart rate and stress responses.
"Climate change is increasing the frequency of hot nights, which may independently contribute to cardiovascular morbidity and mortality by impairing sleep and autonomic recovery," Dr O'Connor said.
"While there are guidelines for maximum daytime indoor temperature, 26°C, there are no equivalent recommendations for nighttime conditions."
Journal Reference: O'Connor, F.K., Bach, A.J.E., Forbes, C. et al. Effect of nighttime bedroom temperature on heart rate variability in older adults: an observational study. BMC Med 23, 703 (2025). https://doi.org/10.1186/s12916-025-04513-0
(Score: 2) by JoeMerchant on Wednesday February 04, @07:08PM (4 children)
Anyone share a bedroom with a woman over 50 years of age, and have any kind of climate control in your room?
I don't think I could get away with a bedroom temperature over 22C, though I remember sleeping just fine in a 30C room in my 20s.
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(Score: 4, Informative) by Gaaark on Wednesday February 04, @10:34PM (3 children)
We sleep at a temp of 20C (and I'd prefer 19C).
My wife sleeps covered up and i sleep with just a sheet and maybe a blanket pulled half-way up. I sleep MUCH better at colder temps (all depending on how my son impacts that sleep, though).
--- Please remind me if I haven't been civil to you: I'm channeling MDC. I have always been here. ---Gaaark 2.0 --
(Score: 3, Interesting) by JoeMerchant on Thursday February 05, @12:54AM (2 children)
Cold is relative, even for us. In summer 68°F (20C) is too cold for us, but in winter it's not too bad - with a warm wool blanket.
In summer, our night time thermostat is usually set to keep us at 72°F (22.22C), and we'll be O.K. at 73°-74°F in the upstairs bedroom, which is always about 2°F warmer than the kids' bedrooms downstairs.
But, then, we grew up and lived in Miami until we were ~35 years old. Back in the 1970s, windows still opened on our homes and our parents would reluctantly turn on the A/C when it was getting to be more than 78°F (25.55C) at bedtime.
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(Score: 1) by jelizondo on Thursday February 05, @01:26AM (1 child)
Oh! You're Florida Man, that explains a LOT.
Sorry, sorry. Just friendly banter, no malicious intent 😜
(Score: 3, Funny) by JoeMerchant on Thursday February 05, @02:32AM
We bought some land and spent some time in a little town in the middle of Florida for a few years.
In that town was another man about my age with my same last name and a similar first name - people would ask if he was my brother, or sometimes assume he was. He had a colorful history of abuse of various drugs, small time dealing, arrests for soliciting prostitutes, etc. Ehhh... no, never met him.
Then there's this guy, who just might be my hero: https://www.fox13news.com/news/florida-man-accused-taking-key-west-conch-tour-train-joyride-having-meth [fox13news.com]
I had celebrated my 57th birthday not too long before - my celebration was nowhere near as epic or even memorable...
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(Score: 4, Insightful) by Tomahawk on Wednesday February 04, @08:11PM (2 children)
I'd have to have the heating on all night to maintain that temperature, even in summer.
I'll stick with my 20°C or less room.
(Score: 4, Interesting) by Reziac on Thursday February 05, @04:18AM
Waaaay too warm. I spent too many Montana winters in a semi-heated trailer where it might be zero to 10 C in there by morning, and even now that I live in a real house just like a real person, in winter I usually keep it around 15-18C at night, and it's probably not that warm when I sleep downstairs next to the big window. When the heat comes on in the morning, when it gets to 20C it wakes me up. I start the night with a down comforter, but by morning it's usually on the chair. Summer nights the big fan is pulling in cool air all night, and it's around 16C by morning. (Needless to say, I don't use the A/C much.)
So, according to this research, I should live forever. :P
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by driverless on Thursday February 05, @11:26AM
Same here, at 24°C I'd be awake half the night unable to sleep due to the heat.
(Score: 4, Insightful) by pTamok on Wednesday February 04, @08:45PM (3 children)
For me 24°C is way too high. 16°C to 18°C seems about right, and I like chillier so long as it is not damp.
As a student, one of the bedrooms I used for a year, in winter, had a reasonably thick layer of ice on the inside of the windows in the morning from my exhaled breath. (Single pane windows) I'll admit to wearing a thick cotton nightshirt, which did have an accompanying hat, which I never needed.
To be fair, the room temperature is pretty much irrelevant so long as you have adequate bed coverings and mattresses. Cotton-covered quilts filled with Eider-duck down feathers [wikipedia.org] work well for the cover. A well-ventilated mattress is also a must, as it needs to be able to remove the water in your perspiration. A cover with the correct insulating factor for the room temperature allows you to keep warm from your body heat alone. I hate being cold in bed, and regard sheets and blankets as entirely inadequate. If you get too hot under a quilt, just stick an arm or a leg out.
I have been required to use hotel rooms where the AC was entirely unable to get the temperature down to something I regarded as comfortable for sleeping. In a couple of places I have had to use a dampened towel as a blanket operating as a 'swamp cooler' where the evaporation cooled me down. It may well be that my body naturally 'runs hot' while I am asleep.
(Score: 4, Informative) by Reziac on Thursday February 05, @04:27AM (2 children)
I don't use sheets at all, because in a cold room (since I seem to think heat at night is optional) sheets are chilly. Instead I use a furry throw, which always feels warm. And over that, a down comforter as needed. It is really astonishing how cold the room can be if the bed is warm -- I lived for years with limited heat in a cold climate, and being cold at night was never a problem. Also, bedsocks work wonders.
Some years back I found a weird blanket that has fairly stiff "fur" and traps heat like nothing else I've seen. It's like an instant space heater. It's more than sufficient at 30F and probably would do the job well below that. (It also weighs about ten pounds, so is perhaps best used as a tent.)
And there is no Alkibiades to come back and save us from ourselves.
(Score: 3, Funny) by driverless on Thursday February 05, @11:28AM (1 child)
So do I, although he's not really a throw but more a self-propelled leap. Also serves as a weighted blanket if he's curled up on your feet.
(Score: 2) by Reziac on Thursday February 05, @11:39AM
LOL, I used to have several of those. The bed could get downright crowded. :)
And there is no Alkibiades to come back and save us from ourselves.
(Score: 3, Insightful) by hopp on Wednesday February 04, @09:01PM
We never keep the house warmer than 19.5° and overnight it's only heated to 13°. I couldn't imagine a house at 24° all the time.
(Score: 4, Insightful) by Freeman on Wednesday February 04, @09:58PM
Pretty sure the until death do us part is the conditional for, if you dare to raise the thermostat.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 4, Interesting) by janrinok on Wednesday February 04, @10:41PM
Nighttime is 18 deg, daytime is 20 deg.
[nostyle RIP 06 May 2025]
(Score: 3, Insightful) by Anonymous Coward on Thursday February 05, @02:39AM (1 child)
Hawaii and some tropical/hot countries seem to have OK life expectancy. Do most people in those places sleep with AC on set to 24C?
https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_life_expectancy [wikipedia.org]
https://en.wikipedia.org/wiki/List_of_countries_by_life_expectancy [wikipedia.org]
From what I see older people acclimatized to warmer climates don't do well when it's cold. They often get pneumonia etc and die (more elderly dying of pneumonia during winter happens in colder climates as well?). Which is ironic because lots of hospitals in warmer climates follow regimes set by countries with colder climates and thus they tend to have very very cold temperatures.
Some say it's to stop the bacteria, fungi, etc from multiplying. The last I checked, the cold is not killing the superbugs in hospitals either: https://floridaphoenix.com/briefs/theres-a-life-threatening-type-of-fungus-emerging-in-florida-and-its-resistant-to-drugs/ [floridaphoenix.com]
See also:
https://www.sciencedirect.com/science/article/abs/pii/S0043135411004854 [sciencedirect.com]
Based on known science most animals that get fevers due to infection have immune systems that prefer warmer not colder. Many patients might actually recover better if you keep them warm (but not too warm of course).
(Score: 3, Touché) by VLM on Thursday February 05, @03:01PM
Could just leave it at that, its around 5 to 10 percent as a cause of death depending who's numbers you use.
I live in the frozen north and we are in "winter" by southerner standards for about ten months of the year. So yeah at least half the people die "in the winter" in that it was recently below freezing, our growing season is only 5 or 6 months depending on how many risks you want to take.
(Score: 2) by fliptop on Thursday February 05, @04:29AM
I heat w/ wood so winter temp can range from 60-mid 70's (F) and in summer I keep the A/C at 78. I don't have a preference for sleeping temp. Covers can be kicked off it it's too hot, and an oscillating and/or ceiling fan is adequate.
Our Constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other.
(Score: 3, Interesting) by ledow on Thursday February 05, @08:23AM (1 child)
I live in the UK.
24C in the bedroom would be a tropical party. We should be living forever if I extrapolate this nonsense.
(Honestly, my aircon / heatpump is set to 20C... and that's true everywhere... my home. My car. My workplace. And for 95% of the year, that's heating or - at best - just maintaining temperature)
(Score: 3, Insightful) by gnuman on Thursday February 05, @11:31AM
https://en.wikipedia.org/wiki/2022_United_Kingdom_heatwaves#Impact_on_health [wikipedia.org]
Yes, I know, it's cold now. It will be cold tomorrow. But this is basic research on stressors for night vs. day.
(Score: 2) by gnuman on Thursday February 05, @11:37AM (1 child)
So, it seems it's cold outside for most people here and we all forgot what warm is. But, if you clicked on the actual article ..
And then they talk about how they looked at people living in retirement homes in Australia.
They are not talking about perfect temperatures or ideal temperatures or what you prefer. They are simply trying to measure at what temperature heat stress is less of a factor for a given population. Yes, this probably doesn't apply to people living in tropical countries all their life. But it's another data point and probably important when it comes to cooling centers during heat waves. You know, in the summer time, when it's warm again.
(Score: 3, Funny) by Reziac on Thursday February 05, @11:49AM
Well, if they were worrying about cooling things down in cold weather, I'd be concerned....
https://www.sciencedirect.com/science/article/pii/S2542519625000543 [sciencedirect.com]
"In Barcelona, the optimal temperature was 23·6°C with the risk increasing steadily for mildly cold days and sharply for hot days. Over 19 years, these risk curves translate to 10772 cardiovascular excess deaths linked to cold and 556 to heat."
And there is no Alkibiades to come back and save us from ourselves.
(Score: 3, Interesting) by VLM on Thursday February 05, @03:07PM
I'm honestly surprised that dew point wasn't the determining factor.
It gets warm and humid a couple weeks every summer and I find it VERY difficult to sleep when the dew point is above 70 or so, without air conditioning (camping, "the old days", uni student housing in late august in the old days, etc)
Assuming you're not dehydrated, your skin will approach the dew point unless you're laying in the sun or way over dressed.
Your nose/throat stabilize temp and to some extent humidity long before air hits the lungs outside really extreme situations (-20F around here a couple weeks ago) so its probably a skin effect rather than a lung effect.