Great balls of fire and the vicious cycle: a study of the effects of cycling on male fertility.

Over the past few years we have been bombarded with publicity telling us to do more exercise in order to reduce our risk of developing heart disease. Also, as commuter traffic increases and petrol prices rise, workers are constantly looking for quicker, cheaper and greener ways of travelling short distances. As a result of this, bicycle sales have risen exponentially. However, as the popularity of cycling increases, so do the fears that spending hours in the saddle every day may not be as beneficial as first thought. For many years now reports in the literature have suggested that exercise in general, and cycling specifically, may actually increase an individual's risk of developing problems in the male reproductive system. In this report I will review the evidence available in the literature, paying special attention to cycling and the risks of developing testicular cancer, secondary impotence and, most importantly, the effects on male fertility.