I had to work this morning so I couldn't do a club ride.

I did have a time window to ride this afternoon, so I did go for a ride.

Conditions were sunny, temp about 90, medium humidity. Not awful but pretty warm.

I went by my general guide to drink 1 bottle/hour...First hour felt reasonably good, I was actually drinking a bit more than that 1 bottle/hr...when I came to a nasty hill (approx 12% grade, but only 1 km long)...I made it to the top and drank more water but I started to feel "off" and really nauseated. I was wondering if maybe I was drinking TOO much water and bloating myself...I limped home and had to "steal" some extra water from a municipal building's spigot on the way home. When I got home it was clear that I was borderline dehydrated and had not had enough fluids in me.

It was "only" a 2 hour ride but I went through 3 bottles and still got overheated and borderline dehydrated.

Other than drink more and avoid riding in the heat, any ideas on how to avoid this from happening?