You just never know
 

Started out my ride today with a pretty intense headache, a stomach that didn't feel real great and an overall blah feeling. I figured I would ride for an hour and see how I felt, if things didn't get better would head home and take it easy. First 20 minutes were a lttle nasty but then the sinuses opened up and cleared out and everything came together, rode 50 miles and had my second fastest averg MPH of the season. It just goes to show you never know how you will feel on a ride. I've also had the opposite where I felt pumped, couldn't wait to get out and then the whole ride felt like I was pedaling in wet concrete.

Have you had this experience before?

Ths dichotomy happens to me almost every time I go out. Feel great...bad ride. Feel lousy...killer ride.

Been there, done that, got the tee shirt.

Some of my fastest times have been when I went out to "get in zone" for cardio. Didn't fell like going anywhere.

My feedback:
I have been able to control my metabolism with consistent food intake, sleep and control of other body functions. All things being equal, my average speed over a 50 mile bike run varies by 1.0 MPH due to these factors. I must say that I will not over-stress my legs for fear of doing permanent damage. But I do go fast. With 700 x 38 tires on limestone I go 17.6 MPH. The trail is undulating flat and it is wind neutral because I go back and forth.

The biggest variable is the weather. Today I ran into extreme rain storms, another day I had 100 degrees with 100% humidity. My best time was (of course) at about 78 degrees and almost no wind.