Why does even 5 minutes of sun cause headache - and 10 mins cause nausea?

i have the same problems.

does it happen in the winter sun? If not it could be allergies in the spring/summer. We all change as we get older.
talk to your your Doc about a Flonase prescrip. or try otc stuff first

staying hydrated, wearing sunglasses and wearing a cool ventilated hat (not a baseball cap) also help me

I have the same issue. If I go outside for more than 4 or 5 min in the sun without my sun glasses on. For me the headaches started around 13, at 18 I discovered sunglasses. Now I work outside all day everyday and don't really get too many headaches. My doctor said that it was because of my eye color, they are a very light blue, any light colored eye is susposed to put you at a higher risk. The problem with this theory is that I also get bad headaches if I'm hungry and don't eat right away, and my latest problem is the rain. It didn't bother me until about a month ago, but if it's hot outside and then all of a sudden it poors and the temp drops it's an instant migrane. So I understand your pain, 4-5 min outside and I have a headache that the only way to relieve is to go inside in a very dark room and sleep. If I'm out for 10 min I'm throwing up... still haven't found a quick fix for that. Anyways I would try sunglasses, I work at a golf course and people pick on me because of my "racoon" eyes, but I don't care because it's better than throwing up. Try "eyejacket" type of sunglasses because they block more of the light

I have had these same symptoms for years. It always happens on hot summer days when I am exerting myself in the sun.
Yesterday, I helped a family member move furniture and it was around 88-F. I was able to go for around 4 hours and then the precursor to the nausea came on: a dull headache. I spent the next 2 hours throwing up with dry heaves so bad, and wretching so bad, that it broke the tiny blood vessels in my face. I spent 2 hours laying on a cold bathroom floor next to the toilet. Whenever this happens, my body breaks out in tremendous sweat and I am drenched from head to toe. After about 2 hours of laying there with a fan on me, it subsided. My body will then go into a chilling effect where I feel extremely clammy. This happens about once or twice every summer. Last year, it happened after trying to remove a tree stump in the backyard. The only thing you can do is lay down with air blowing on you and wait till it subsides.
I know that it has nothing to do with hydration as I continuously drink water during all my time in the sun. I hypothesize that it has to do with a sun allergy.
I've learned to try to control it as I only cut grass after 6 pm and stay away from doing outdoor activities during the heat of the day.
I've had this go on for as long as I can remember and the only thing I can link it to is the sun exposure. I can be inside and run 3 miles on a treadmill and sweat profusely but it won't cause my symptoms.

My wife gets migrane headaches within minutes of going into bright sunshine. The often last for hours. I am curious if anyone has any ideas that might help. Someone told her chugging a bottle of Gatorade sometimes helps. It has helped her a couple of times, but not always. Maybe the person who made the suggestion is a Gatorade salesman. We are open to suggestions.