Originally Posted by aliasfox

You say you're riding in NYC - are you riding surface streets, laps of Central Park, or Greenways? Surface streets and greenways have a lot of stop and go, especially if you're trying to keep pace with traffic - sprinting can definitely take it out of you. I laid down 1000 miles last year, almost exclusively on Manhattan city streets - figured it was the best way to get exercise while avoiding riding into other peoples' breath like you would on the Greenway or Central Park. If needed, I could sprint at the same speed as traffic, but it'll definitely take it out of you!

My typical distances are 20-50 miles, with the 50 mile ride being the 9W (Manhattan West Side Greenway, across the GWB, onto 9W, turn around at The Filling Station). For any ride longer than 25 miles, I consider bringing a gel and Clif bar - would rather have and not need than the other way around. The gel (I use SIS/Science in Sport) is good for getting some electrolytes, as I don't like putting Gatorade in my bottles (nasty to clean out). I eat when I get home, and for those longer efforts I'll take a ~45min nap afterwards, followed by a liberal dosing of iced coffee. I actually find it much better to move around for the rest of the day (walking, a light hike) than to lie on the couch, as my muscles seize and make it more difficult to move afterwards.

I would say taking a bit of time to recover after 2-3 hrs of exercise is normal. Take it slow and work your way up to being comfortable with your 40 mile rides. However, if you're still de-energized for hours after a bit of conditioning, it may be time for a checkup.