Endurance training and hair loss.
The connection between exercise and hair loss is often misunderstood. Distance running, intense strength-training, swimming, bicycling, or any intense and prolonged exercise by itself does not cause hair loss as long as you consume adequate calories and nutrients, stay hydrated and don't lose excessive amounts of weight.
The side effects of some of these activities (sun, wind, water) can be hard on hair, however. If you undertake an intense physical training regimen, give your hair protection from injury too by using products with SPF protection.