Yesterday I saw the 8-time bodybuilding champion die suddenly due to fitness; today I saw Zhang Xuefeng die suddenly on a treadmill. If you truly love running, that's understandable, just be mindful of the risks. If running is for health, for most people, it is a relatively inefficient and high-risk form of exercise. For the average person, it's best to check your heart rate and maintain zone 2 while doing uphill walking like the elderly. Efficient fat burning, no risk, and no knee injuries.