Not running down the benefit of fitness. By far, I think a person harms their health more by a lifetime of screen watching rather than triathlon training.
Defining fitness as what we are able to do and health as what our organs can do for us.
There can come a time when our fitness hurts our health. It could happen in one event or as a cumulative effect.
Have you had experience(s) where your fitness was detrimental to your health? Once this happened did you modify your training or approach to fitness? Your guidelines?