Marathon running is much more regulated now.

In 2016, when I ran my first marathon, there was no medical exam; you could sign a waiver and register. The same applied to the championships and Category A gold standard.
At 20, I believed the secret to longevity was:
1) Strict dietary control (high protein, low fat, low carbs)
2) Regular sleep schedule
3) Consistent exercise (gym + over 4 times a week of 5KM runs, over 3 times a month of 10KM runs, regular marathons)
At 30, I believe the secret to longevity is:
1) As long as health indicators are fine, eat whatever you want, otherwise make targeted adjustments.
I believe in scientific analysis of the theorem—change what needs to be changed, add what needs to be added. Just dismiss generic, empty talk as nonsense.
2) Any bedtime is fine, as long as you get enough sleep.
3) Avoid unnecessary hardship, stick to light exercise.
4) Everything is someone else’s fault; I have no problems. No rush, no internal conflict.