# What's the deal with those big honking headaches after all day under the sun? **URL:** \ **Category:** Factual Questions\ **Created:** [May 31, 2005, 2:10pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213 "2005-05-31T14:10:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Carnac\_the\_Magnificent](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Carnac\_the\_Magnificent](https://boards.straightdope.com/u/Carnac_the_Magnificent)\ **Post date:** [May 31, 2005, 2:10pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/1 "2005-05-31T14:10:31Z")
This weekend, I spent an entire day on the beach. By day’s end, I had one of those pounding headaches. Thinking back, I recall similar headaches from other sun-filled days, either gardening all day or doing some rafting, boating or kayaking. What causes this? Is it dehydration? (A friend suggested low-grade sun poisoning.) These few headaches resemble the low-blood-sugar type I get when I have been too busy to eat all day. This weekend, however, I ate well, tho I drank little fluids on the beach (and touched no alcohol). ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [May 31, 2005, 2:31pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/2 "2005-05-31T14:31:56Z")
I vote for dehydration ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [May 31, 2005, 2:35pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/3 "2005-05-31T14:35:40Z")
Could be dehydration, or could (WAG) have something to do with the bright sunlight shining in your eyes all day. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [May 31, 2005, 3:09pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/4 "2005-05-31T15:09:36Z")
Another vote for dehydration. ---
**Author:** ![Little\_Bird](https://avatars.discourse-cdn.com/v4/letter/l/3ec8ea/32.png) [@Little\_Bird](https://boards.straightdope.com/u/Little_Bird)\ **Post date:** [May 31, 2005, 3:12pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/5 "2005-05-31T15:12:50Z")
I get these after sitting in a sunny location for an hour or so, indoors or out. I doubt mine are dehydration, I think it’s just a combination of “Too Bright” and “Squinty Stress.” I try to wear sunglasses and that seems to help. 🆒 ---
**Author:** ![Mr.Moto](https://avatars.discourse-cdn.com/v4/letter/m/9de0a6/32.png) [@Mr.Moto](https://boards.straightdope.com/u/Mr.Moto)\ **Post date:** [May 31, 2005, 3:23pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/6 "2005-05-31T15:23:56Z")
I vote for a migraine. Bright light can be a trigger, as can dietary changes. The fact that you’ve linked the two in a similar-feeling headache is key. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [May 31, 2005, 3:32pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/7 "2005-05-31T15:32:02Z")
My vote is for your headache telling you to stop being out in the sun all day on a sandy beach with sun glare off the water. I suppose the beach had dazzling white sand like at Fort Walton Beach, FL. ---
**Author:** ![Carnac\_the\_Magnificent](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Carnac\_the\_Magnificent](https://boards.straightdope.com/u/Carnac_the_Magnificent)\ **Post date:** [May 31, 2005, 5:34pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/8 "2005-05-31T17:34:13Z")
> [@David Simmons](#): > > My vote is for your headache telling you to stop being out in the sun all day on a sandy beach with sun glare off the water. I suppose the beach had dazzling white sand like at Fort Walton Beach, FL. I was wearing dark, polarized, 100 percent UV A/B-filtering shades. Sunblock part of the day. Migraines? Never have them, knock on sand. Also never have these headaches when outside for, say 2-3 hours, but yes if for a long time. Also get them when I haven’t eaten much all day. Once it comes, relief takes a few hours. Dehydration sounds likely. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [May 31, 2005, 5:45pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/9 "2005-05-31T17:45:04Z")
Happens to me, too, and I’ve always assumed it was dehydration. ---
**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\ **Post date:** [May 31, 2005, 5:57pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/10 "2005-05-31T17:57:34Z")
I vote muscle tension…from squinting. I bet you don’t wear your sunglasses every second you are out in the sun. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 31, 2005, 8:16pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/11 "2005-05-31T20:16:39Z")
> [@ultrafilter](#): > > Another vote for dehydration. Or possibly a caffeine withdrawal headache because you’ve spent all day out in a natural environment, coffeeless, rather than huddled in front of a computer screen guzzling can after can of Jolt cola. ---
**Author:** ![BiblioCat](https://avatars.discourse-cdn.com/v4/letter/b/ed8c4c/32.png) [@BiblioCat](https://boards.straightdope.com/u/BiblioCat)\ **Post date:** [May 31, 2005, 10:31pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/12 "2005-05-31T22:31:31Z")
If the headache went away with a regular dose of OTC medicine like Advil, it probably wasn’t a migraine, although long hours in bright sunlight can be a migraine trigger. It certainly is for me. I’m thinking it was a combination of squinting in the sunlight and dehydration. Stay out of the sun for long stretches, and drink plenty of water. ---
**Author:** ![Cat\_Whisperer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cat_whisperer/32/4839_2.png) [@Cat\_Whisperer](https://boards.straightdope.com/u/Cat_Whisperer)\ **Post date:** [June 1, 2005, 12:01am UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/13 "2005-06-01T00:01:01Z")
I get the same thing - a relentless headache that isn’t touched by OTC meds after too much sun. I don’t drink _any_ caffeine, and I’m usually well-hydrated, so that isn’t it for me. I have found that wearing sunglasses and a hat whenever I go out in the sun helps a lot. I think it is a touch of sun-stroke and/or a bright light triggered migraine. ---
**Author:** ![Queen\_Bruin](https://avatars.discourse-cdn.com/v4/letter/q/e274bd/32.png) [@Queen\_Bruin](https://boards.straightdope.com/u/Queen_Bruin)\ **Post date:** [June 1, 2005, 1:09am UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/14 "2005-06-01T01:09:10Z")
I vote for mild sunstroke. That sun can be a nasty bugger. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [June 1, 2005, 1:32am UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/15 "2005-06-01T01:32:03Z")
> [@Reeder](#): > > I vote muscle tension…from squinting. I bet you don’t wear your sunglasses every second you are out in the sun. I agree. Having been to the vast majority of my college’s home games for the past 15 years, I can say that as far as day games are concerned: If I forget my sunglasses, I have a splitting headache by the end of the 4th quarter, regardless of temperature (I recall the worst headace being on a bright cool day after a cold front, actually) If I don’t forget the sunglasses, then I never do get a headache. Sunburned and a little dehydrated, yes, but my head never hurts. ---
**Author:** ![Malodorous](https://avatars.discourse-cdn.com/v4/letter/m/e47774/32.png) [@Malodorous](https://boards.straightdope.com/u/Malodorous)\ **Post date:** [June 1, 2005, 1:50am UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/16 "2005-06-01T01:50:33Z")
> [@Carnac the Magnificent!](#): > > These few headaches resemble the low-blood-sugar type I get when I have been too busy to eat all day. This is exactly what I experience, I have a headache and am tired as if my blood sugar was very low. Not sure why but being out in the direct hot sun all day makes me exhausted, leading to headaches exactly as you describe ---
**Author:** ![shijinn](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@shijinn](https://boards.straightdope.com/u/shijinn)\ **Post date:** [June 1, 2005, 6:42am UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/17 "2005-06-01T06:42:05Z")
> [@Carnac the Magnificent!](#): > > … I was wearing dark, polarized, 100 percent UV A/B-filtering shades. Sunblock part of the day. … did you wear a hat? ---
**Author:** ![Carnac\_the\_Magnificent](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Carnac\_the\_Magnificent](https://boards.straightdope.com/u/Carnac_the_Magnificent)\ **Post date:** [June 1, 2005, 12:36pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/18 "2005-06-01T12:36:51Z")
> [@shijinn](#): > > did you wear a hat? Most of the time, yes, though I find I can get these headaches more easily if my head isn’t allowed to, um, ventillate better. Frankly, I don’t see how people wear caps in hot weather. Doing that tends to overheat me and, no, I am not overweight or deconditioned. Weird. Sounds like the best-fit answer is: dehydration. I’m guessing that, during 6 hours under the hot sun, a person needs to drink probably 6-7 glasses of non-alcoholic fluids. During that period, I might drink 2-3. ---
**Author:** ![LionelHutz405](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lionelhutz405/32/536_2.png) [@LionelHutz405](https://boards.straightdope.com/u/LionelHutz405)\ **Post date:** [June 1, 2005, 1:30pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/19 "2005-06-01T13:30:58Z")
> [@Carnac the Magnificent!](#): > > Frankly, I don’t see how people wear caps in hot weather. Doing that tends to overheat me Me too. I find some hats seem to hold in so much heat I actually feel worse than when I don’t wear one. I’ve found those ‘just the brim’ types that golfers wear help a lot. You get the brim to keep the sun out of your eyes, but the top is open to allow your body heat to escape. ---
**Author:** ![Cat\_Whisperer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cat_whisperer/32/4839_2.png) [@Cat\_Whisperer](https://boards.straightdope.com/u/Cat_Whisperer)\ **Post date:** [June 1, 2005, 10:32pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-those-big-honking-headaches-after-all-day-under-the-sun/306213/20 "2005-06-01T22:32:53Z")
I’m just the opposite - I hate hats, but if the sun beats down on my dark brown hair all day, I’m _going_ to get a headache, so I wear a light-coloured hat to reflect the sun’s rays instead of them soaking into my head.