Vision blur, nausea when hiking?

its fatigue. obviously your not drinking enough water. drink gatorade too or something sweet. you need the electrolytes in the body, not just water. when you sweat you sweat out all the salt in your body. water doesnt replenish that, but gatorade or drinks along those lines do. but also drink water. also, eat. if you dont you wont have energy.

your body might not be able to withstand what your doing to it. maybe take it back a mile or two till you get adjusted to it, then slowly pick up the pace and mileage.

your symptoms are that of dehydration, so just keep hydrated and youll be fine.

Oh no, migraine. :-( Have you eaten and slept enough? Some people have a tendency to migraine while others only get them if they are very tired or have not eaten - the clue is the nausea and brightness. Is the headache one sided? That would confirm it. The only thing to do is lie in a dark room and drink lots and eat carbs even if you really don't feel like it. If it keeps happening there are good meds. I get them very badly and take tablets 5 times a day but there are tablets you can have just when you get one that are quite good.

take your glucometer with; you and check your glucose levels when you are feeling that way. It usually means my glucose is going under 65 mg/dL so I need to sit and have a snack and definitely a bottle of water.

Listen to Nana. Where you are, someone would find you. Where I go hiking, they won't find the body until the buzzards start circling.