Originally Posted by Veloria

I've been riding my fixed gear roadbike since July. At first only 25% or so of my rides were on this bike (the rest being on a geared roadbike), but as winter approaches it has become more like 95%. The bike is very comfortable and I never feel tired while I am riding it. But strange things happen to me after the rides. I have no appetite after coming home, and have to force myself to eat. And when I fall asleep, I want to sleep for like 12 hours - which is not normal for me at all. I will also often get a fever after the ride (2-3 hours later) and even a sore throat - both of which will go away after I sleep. None of this ever happens to me when I ride a geared roadbike on the same route. What's going on - Is fixed gear riding so much more strenuous that it's inducing some sort of crazy "over-exercised" immune system response? The distances I am riding are 30-40 miles with mild hills and I had never ridden a fixed gear bike prior to this summer.