I have a good friend who used to be into the Iron Man and Marathon stuff. He is in great shape and is 60 plus years old. His Dr told him to stop and keep his exercise limited to walking and light cardio. The Dr told him these extreme events put a lot of stress on the body and heart even for someone in shape. The Dr said these exercise/training events do not have long lasting benefits and and are unnecessary. He likened it to a Race car engine that runs hard during a race and unexpectedly fails. Now if I could just get the motivation to walk and do light cardio....
I’ve heard High-Intensity Training is the way to go. Five minutes of alternating between all-out sprints and resting, will beat two hours of cardio.
I can see the doctor’s point, however, some doctors have the notion that during a marathon or a bicycle road race, the athlete is running continuously at maximum heart rate, which is not the case. Maintaining max HR for that amount of time is not possible. A pro racer is not running anywhere near max during a 3 to 6 hour training ride, maybe he’s cruising along at 120-130 bpm, maybe lower. Different metabolic processes are involved in each exercise “zone”. Exercise physiology is a topic still not adequately covered in medical schools. Thirty years ago, 1 hour total was all that was spent on the topic. Now it is 2 3 hour lectures. Not credit hours, clock hours. It is still not sufficient.