Originally Posted by
mcafiero
So basically I attribute it to over-exertion on my rides.
You mean ... serious dehydration on your rides.
Before your next ride (this weekend?) ...
-- on the day before, make sure you drink at least 8 cups (2 litres) of water, fruit juice, or whatever you prefer (not alcohol). You should be urinating almost clear and fairly decent amounts all day.
-- on the morning of the ride, while you're getting ready to go ... drink a tall glass of water. Just plain ordinary water. You can also have a cup of coffee or glass of orange juice or bottle of Ensure or whatever you normally drink before a ride, but have that tall glass of water too.
Then when you get on the bicycle, right away start drinking one 750 ml bottle every 1 to 1.5 hours ... more frequently if it is hot, windy, or you're exerting yourself a lot. Don't forget to eat something with a bit of salt mid-ride.