This is an interesting bit from Runner’s World on why an ultramarathon (50-100 miles) could be easier on your body than just a simple marathon:
I’ve heard people say ultras are easier on your body than marathons. How could that be?
From the intensity standpoint, it’s easier. You’re going at a moderate rate over a longer period of time. You’re stopping at aid stations, you’re getting something to eat, refilling your water bottle. In marathons, you go, say, three and a half hours at the exact same pace over pavement. Most ultra courses have a variety of terrain, so you’re using different muscles. Even the outlook is different: I’m going to walk for 30 minutes, then I’m going to run downhill for 40 minutes. That’s completely different from I’ve got an hour and 15 minutes of First Avenue ahead of me.
Thanks to Paul Kedrosky for the pointer, who asks what the business parallels are. My takeaway from the above is that variety is key — change of activity, change of scenery, etc. It makes sense that going hard for six months is easier than going hard for three months, if the six month plan involves some a mix of tasks and perhaps a few weekend get-aways.
Life is a series of sprints, not a marathon. So says the Power of Full Engagement, a book that has influenced my thinking on balance issues.