The biggest risk one runs when preparing for an endurance event, or even just exercising to “stay in shape” is overtraining.  Some people call it “burnout.”  The cause is simple:  doing too much too soon.  Some of the symptoms include persistent tiredness, heavy feeling in the legs, inability to complete scheduled training rides, sleep disturbance, lack of appetite, constipation or diarrhea, anxiety, depression, irritability, loss of enthusiasm, and an inability to concentrate.  The cure is to stop or severely curtail your training.  Ask anybody who’s tried, though.  Cutting down on your training when you feel the need to do more and more is very difficult.  It’s best not to get into the trap, and most books on running or bicycling will give you hints for avoiding overtraining.

I was starting to experience some symptoms of overtraining (loss of sleep, especially), and during today’s 38 mile  ride my legs were uncharacteristically sore and heavy.  So this next week I’ll be doing the miles, but at a much lower speed in order to let my body rest a bit.  I’ll see how I do on next week’s ride, and decide then if I need to rest a little more.