https://www.nytimes.com/2017/04/12/well/move/an-hour-of-running-may-add-seven-hours-to-your-life.html
http://www.medicaldaily.com/life-expectancy-runners-vs-non-runners-running-2-hours-week-any-speed-mileage-415554
“the gains of life expectancy are capped at around three extra years, no matter how much people run.” ......"improvements in life expectancy reach their peak at about four hours of running per week, but they did not decline. Meanwhile, walking, cycling, and other activities boosted lifespan, but not at the same rate."
