2020 fasting change
You said recently that you switched to 3-day fasts once a month from 7-day fasts once a quarter saying it was a similar number of days (36 vs. 28). But on the 3-day fast you reach your target only on the 3rd day, so 12 on-target days per year, whereas for the 7-day you are on target for 5 days (days 3-7), so on target days are 20. Have you considered a 5-day fast (3 days on target) six times a year (30 days total, 18 on target)? Less total days, more on target than the once a month.
Aerobic Exercise effects on heart
Peter, I, like you, am a lifelong endurance athlete. I'm now 56 and still train roughly 15 hours a week on average, split between swim-bike-run, though mainly bike. As recently as pre-Covid I was doing 25-30 hours per week (mostly on the bike), with several high intensity sessions per week. In the last couple of years I've read about potentially adverse effects of exercise on the heart and I have listened to your podcast with James O'Keefe a couple of times. Yet you have said recently that you want your patients to be in the elite group of aerobic performance, a decade younger than themselves, and you seem to advocate for significant Zone 2 and VO2 Max workouts to achieve this. Question, is there data that would establish the line between too much and not enough? Is it intensity based? Cumulative time?