# Hot Weather Sleepiness ?
**URL:** https://boards.straightdope.com/t/hot-weather-sleepiness/115564
**Category:** Factual Questions
**Created:** [June 23, 2002, 2:57pm UTC](https://boards.straightdope.com/t/hot-weather-sleepiness/115564 "2002-06-23T14:57:54Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@dragongirl](https://boards.straightdope.com/u/dragongirl)
#### Post date: [June 23, 2002, 2:57pm UTC](https://boards.straightdope.com/t/hot-weather-sleepiness/115564/1 "2002-06-23T14:57:54Z")
[Whiney] It’s sooooo hot![whiney]
It’s about 90 degrees her and I’m usually pretty energetic, but when it gets this hot, I can’t seem to do anything.
Why does the heat make me so tired ?
Does it make everyone tired ?
Thanks.
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### Author:  [@kiz](https://boards.straightdope.com/u/kiz)
#### Post date: [June 23, 2002, 3:15pm UTC](https://boards.straightdope.com/t/hot-weather-sleepiness/115564/2 "2002-06-23T15:15:19Z")
I don’t know if it’s the heat _per se_ or the humidity, but the phenomonon knows no bounds. As you’ve witnessed, the hotter it gets, the more lethargic everyone/everything is. There’s a stereotype out there which claims heat is the reason why southerners are (pardon me, I’m paraphrasing here) “slow” when it comes to day-to-day moving around.
I know this doesn’t exactly answer the question, but I’m so glad you asked it – I’ve been wondering myself!
🙂
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### Author:  [@dwc1970](https://boards.straightdope.com/u/dwc1970)
#### Post date: [June 23, 2002, 6:14pm UTC](https://boards.straightdope.com/t/hot-weather-sleepiness/115564/3 "2002-06-23T18:14:18Z")
I don’t have an online cite handy, but in David Feldman’s book called _When Did Wild Poodles Roam the Earth_ this question is addressed.
> [@](#):
>
> There is no doubt that heat saps us of energy. Many Latin, Asian and Mediterranean cultures routinely allow their work force to take siestas during the hottest portion of the day, aware both that productivity would slacken during the early P.M. hours without a siesta and that workers are refreshed after an hour or so of sleep.
>
> Yet all of the sleep experts we consulted agreed with the declaration of the Better Sleep Council’s Caroline Jones: “Heat is not what makes us sleepy in the afternoon. Researchers have documented a universal dip in energy levels that occurs in the P.M. regardless of the temperature.” These daily fluctuations of sleepiness within our body are known as “circadian rhythms.” David L. Hopper, president of the American Academy of Somnology, told _Imponderables_ that late evening and early afternoon are the “two periods during the twenty-four-hour cycle when sleep is possible or likely to occur under normal conditions.”
>
> Some sleep specialists believe that circadian rhythms indicate humans have an inborn predisposition to nap. But somnologists seem to agree that the natural sleepiness most of us feel in the afternoon, when it happens to be hottest outside, has little or nothing to do with the other very real enervating effects heat has upon us.
>
> Environmental temperatures _do_ affect our sleep patterns, though. Most people sleep better in cool environments, which explains why most of us are restless when trying to sleep in hot rooms even when we are exhausted at night. And if the temperature should shift while we are asleep, it can cause us to awaken, as Hopper explains:
>
> > [@](#):
> >
> > Our body temperature is lowest in the early morning hours and highest in the evening. During deep NREM and REM sleep, we lose our ability to effectively regulate body temperature, so if the outside temperature is too warm or too cold, we must arouse somewhat in order to regulate our body temperature more effectively. During sleep we are not unconscious, so signals are able to get through to arouse us when needed, much as we awaken from sleep when we need to go to the bathroom.
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### Author:  [@sailor](https://boards.straightdope.com/u/sailor)
#### Post date: [June 23, 2002, 7:29pm UTC](https://boards.straightdope.com/t/hot-weather-sleepiness/115564/4 "2002-06-23T19:29:22Z")
In tropical climes there are certain times of day
When all the citizens retire
To take the clothes off and perspire.
It’s one of those rules that the greatest fools obey
Because the sun is far too sultry
And one must avoid its ultraviolet ray.
The natives grieve when the white men leave their huts
Because they‘ re obviously, definitely nuts!
Mad dogs and Englishmen go out in the midday sun.
The Japanese don’t care to,
The Chinese wouldn’t dare too.
Hindus and Argentines sleep firmly from twelve to one.
But Englishmen detest a siesta.
In the Philippines they have lonely screens
To protect you from the glare.
In the Malay States there are hats like plates
Which the Britishers won’t wear.
At twelve noon the natives swoon,
And no further work is done.
But mad dogs and Englishmen go out in the midday sun…
The toughest Burmese bandit
can never understand it,
in Rangoon the heat of noon
is just what the natives shun,
they put their satchel down
and lie down;
In the mangrove swamps
where the python romps
there is peace from twelve 'til two;
even caribous lie around and snooze
'cause there’s nothing else to do;
In Bengal, to move at all,
is seldom if ever done
But mad dogs and Englishmen
go out in the midday Sun
Noel Coward 1899-1973