I have been biking for years. I am a 62 year old female in average shape and have never had a problem like this until last summer. When it is hot out, and I climb a steep hill or long incline, I feel nauseous at the top of the hill and sometimes throw up. Today it was not even that hot...81 here in NC and I still got sick. I drink lots of water....at least I think I drink enough. Today I ate a granola bar right before the ride and thought maybe I need to eat at least 1/2 hour before I ride. I have researched this online and can't seem to find anyone else who experiences this. I just want to learn what to do to keep this from happening. It's very frustrating because otherwise I am a decent rider and I like to ride hills as it increases my workout. It doesn't feel like heat exhaustion as the only symptom is nausea. I'd be happy to hear your thoughts. Thanks