I ride to work three days a week, 45 miles RT. Going to work is a breeze. My pedaling feels strong and I usually average 15+mph. However, the last few weeks, my rides home have been really lagging. It feels like I'm riding with my brakes engaged. I can't seem to average any faster than 13 mph.

I'm trying to figure out if I need to eat more in the afternoon, I'm simply getting old or if it is just the heat.
Heck, maybe I should invest in some EPO

Anyone out there experienced anything similar, (riding strong in the morning and dragging in the evening)?

If so, how did you overcome it or are you still dealing with it?

Thanks.