False... This is a very false way of thinking, and a very dangerous way of thinking as well. Many people exercise because of the benefits you see for ones health, however there are a lot of things that can go wrong. Cardiac Arrest, possible collapses, dehydration, overexertion, exercise induced asthma, or exacerbation of asthma and COPD. There also a lot of ways to get injured....
This is why first aid is an inherent must for any staff member of a fitness organization. You can't merely standby for such things as cardiac arrest to be treated by EMS.... Every minute counts.