# Does sunlight itself make you tired? Why? **URL:** \ **Category:** Factual Questions\ **Created:** [July 11, 2008, 7:05pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170 "2008-07-11T19:05:28Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [July 11, 2008, 7:05pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/1 "2008-07-11T19:05:28Z")
I love the sun, and heat. But taking my shirt off and getting lots of full-on sun even for just five or ten minutes makes me want to go inside and take a nap. That’s what I just did. I almost never can nap during the day. Wish I could more often, but it just ain’t happening. Then a little time shirtless in full, hot sun and I’m overcome with a tired lethargy; gotta sleep! Why? If it’s hot at night, I can’t sleep, so it’s not just the heat. It seems to be exposure to the sun, then shade that triggers a sleep reflex, hot or not. ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [July 11, 2008, 7:18pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/2 "2008-07-11T19:18:53Z")
Do you also enjoy feasting on the blood of the living? Because if so I think I can diagnose what your problem is. More seriously, usually when I hear people complain about the sun making them tired, they’re talking about a few hours of exposure wearing them out, like how people coming back from the beach are always wiped out even if all they did there was sit on a towel and read. I suppose due to some mixture of dehydration and sunburn. But I’ve never heard of anyone being exhausted by just a few minutes of exposure. ---
**Author:** ![Gala\_Matrix\_Fire](https://avatars.discourse-cdn.com/v4/letter/g/4da419/32.png) [@Gala\_Matrix\_Fire](https://boards.straightdope.com/u/Gala_Matrix_Fire)\ **Post date:** [July 11, 2008, 7:52pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/3 "2008-07-11T19:52:18Z")
I have no factual information, but if you open a poll thread in IMHO I’ll be happy to tell you that sunshine makes me sleepy, too. ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [July 11, 2008, 7:57pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/4 "2008-07-11T19:57:32Z")
[QUOTE=Gala Matrix Fire] I have no factual information, but if you open a poll thread in IMHO I’ll be happy to tell you that sunshine makes me sleepy, too. [/QUOTE] I won’t start a new thread but if it appears a factual answer isn’t forthcoming, I’m more than happy to have a mod move this to IMHO and treat it as a poll. ---
**Author:** ![Oy](https://avatars.discourse-cdn.com/v4/letter/o/bc8723/32.png) [@Oy](https://boards.straightdope.com/u/Oy)\ **Post date:** [July 11, 2008, 9:35pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/5 "2008-07-11T21:35:48Z")
Here’s another piece of data. Sun in a car, even in the winter, makes my entire family drowsy. That is, when you’re sitting in a car and the sun is beating down. Probably especially in the winter - in the summer it’s too hot. ---
**Author:** ![Antinor01](https://avatars.discourse-cdn.com/v4/letter/a/ecae2f/32.png) [@Antinor01](https://boards.straightdope.com/u/Antinor01)\ **Post date:** [July 11, 2008, 9:40pm UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/6 "2008-07-11T21:40:51Z")
Makes me sleepy as well. It also makes me sneeze. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [July 12, 2008, 12:08am UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/7 "2008-07-12T00:08:11Z")
Hmmm…many creatures rest when it is hot out. My educated guess is that this is a built in reaction by your body to conserve energy, focus on cooling and prevent dehydration. Survival-wise, it’s better to have a natural tendency to stay hydrated and rested than it is to have a natural tendency to want to run around, overheat, dehydrate in the sun and increase the chance of death. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [July 12, 2008, 12:11am UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/8 "2008-07-12T00:11:46Z")
Many years ago, I lived in an apartment right on the beach, in Long Beach, NY (on the southern shore of Long Island). I was working the graveyard shift in Manhattan, and was having a helluva time trying to sleep during the day in summer, what with the beach crowd’s noise and kids playing basketball next door. I discovered that if I went out to the beach, with lots of sunscreen, I could get at least a few hours of sleep, then come inside and go immediately to bed. ---
**Author:** ![Stathol](https://avatars.discourse-cdn.com/v4/letter/s/71e660/32.png) [@Stathol](https://boards.straightdope.com/u/Stathol)\ **Post date:** [July 12, 2008, 1:34am UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/9 "2008-07-12T01:34:47Z")
[QUOTE=Antinor01] Makes me sleepy as well. It also makes me sneeze. [/QUOTE] Behold, the [photic sneeze reflex](http://en.wikipedia.org/wiki/Photic_sneeze_reflex)! You are not alone. ---
**Author:** ![Oy](https://avatars.discourse-cdn.com/v4/letter/o/bc8723/32.png) [@Oy](https://boards.straightdope.com/u/Oy)\ **Post date:** [July 12, 2008, 3:41am UTC](https://boards.straightdope.com/t/does-sunlight-itself-make-you-tired-why/456170/10 "2008-07-12T03:41:55Z")
Welcome, **Stathol**. We like that kind of early post around here. Brief, factual, includes a cite. Keep up the good work! 🙂