Heat Exhaustion or something else?
I went biking yesterday and covered just under 12km. I was going at a relatively casual speed, though would go quicker when going uphill. I do this trail often. About 8km in I felt all right, I was a little sweaty and tired but still felt energized. Once I reached the top of a big hill, the second I stopped, I felt absolutely exhausted- I could barely stand or do anything. I couldn't get enough air, was breathing rapidly and I thought I was going to faint. It was quite scary, and I struggled for balance and was incredibly nauseous. It lasted a long time, and while trying to recover I kept having to stop because I could barely walk. I am still on a waiting list to see if I have exercise-induced asthma, so I believe my difficulty breathing along with the heat and humidity may have caused heat exhaustion. I'm positive that if I'd kept biking the way I had been for another five minutes I would have passed out, vomited and been unable to breathe, and that I may have been in a dangerous situation. With what I've described, is it possible that I had heat exhaustion? What can I do to protect myself if I find myself in similar circumstances again?