http://www.scoobysworkshop.com/body-shaving/
YES, this is fitness related. In hot weather, cardio performance is often limited by how much heat you can dissipate. Your muscles ability to work is diminished as core temperature rises as a self-regulating mechanism to keep the body at a safe temperature. Body hair is insulation and it slows evaporative cooling. Remove the body hair and it increases your heat dissipation thru evaporative cooling and thus raises your ability to perform in hot weath