Just grit your teeth and work through the pain, basically :) That's what I did. If you have intestinal candida then biking is going to make you feel worse then you've ever felt before. It was biking that cured me of my yeast infection. Just biking for 30 min. made me feel nauseaous for days afterwords. I figured out how to deal with it, though. Sweating, drinking water, and Liver Flushing will all cut those die-off symptoms by over 50% (it made biking die-off bearable for me). If you have die-off symptoms really bad after biking, it means your liver is overloaded and it's time for a cleaning. I will warn you, though, that Liver Flushing may make it all seem worse for the first day or two but eventually you will be able to tell the difference. Try Shelley's recipe for the cleansing carrot salad. It's not a true liver flush, but it will make you feel A LOT better when you bike. The general rule with Liver Flushing is that the worse you feel, the more successful the flush, so I would recommend eating the salad at night so that you'll sleep through all the discomfort that accompanies liver cleansing.
Anyways, good luck! It's a long battle but eventually this yeast infection will go away! :)