Primal Movement for Longevity
Our digestive systems evolved over millions of years, and our genes have also learned to respond to certain physical demands we've been placing on them throughout humans' history. Mark Sisson, author of ‘The Primal Blueprint’ a book and author I highly recommend, believes in what he calls a primal exercise pyramid. It is as follows: Lift heavy things once in a while (roughly twice a week, as little as 10 to 30 min each session is possible), Sprint (all out effort) once a week(less than 5 minutes actual full blown sprinting), and move frequently at a slow pace, 2 to 5 hours total per week.
(Graphic from the 'Primal Blueprint' by Mark Sisson, I highly recommend this book!)
This is based on what humans have been doing for hundreds of thousands of years. As hunter gatherers we spent a good amount of time moving at a slow pace; walking on hunts, walking to gather supplies or scout, than walking back to home camp. Every once in awhile we needed an all out sprint, to hunt, or to survive being hunted! We would also carry carcasses back to camp, or firewood and other supplies, or possibly move heavy rocks and wood to build shelter. Each time we lift a heavy load, our muscle fibers tear slightly, our genes than signal the body to repair them, making them slightly larger, anticipating this load (or larger) for next time. Each time we sprint, our body repairs the muscles and makes them more efficient, knowing we might need to run FASTER next time. As far as moving frequently at a slow pace, there are a myriad of health benefits, the biggest benefit being in keeping our body limber and keeping our metabolism up.
For longevity, I would recommend lifting weights/strength train two to three times per week, sprinting once a week, and moving at a moderate pace (walking, jogging, cycling, etc.) 2 to 5 hours per week, everyday basically. Even a 15 minute walk everyday can do wonders for our metabolism. One does not have to lift weights to strengthen muscles. There are unlimited body weight exercise options one can do to tear those muscle fibers. I will also always suggest yoga for over-all longevity. There are just too many mind and body benefits of yoga to ignore from reducing stress, helping focus, improved circulation, building muscle, flexibility, etc. (a google search of "health benefits of yoga" yields over two and half million results).