You need to keep the blood drifting efficiently through the veins for longevity sake. Fortunately, it requires less effort than you would expect to maintain your health and youth.
One great thing about drifting/hitchhiking is that you can get plenty of exercise walking down the side of the road with a backpack. I would typically walk anywhere from 10 to 50 miles over the course of a multi-state hitch (remember, though, its illegal to walk the side of the interstate).
Below are some daily minimums I would incorporate into your daily living. Considering the long roads ahead of you (with a 10 to 60lb backpack), we recommend the following daily minimums:
20 – Pushups;
20 – Situps;
5 – pullups;
9 minute mile;
*At the very minimum, I would stay in shape by walking and using the stairs everywhere…walking is probably your most important, low-impact, exercise, and the key to your mobility no matter what age. It’s easier on the knees compared to jogging, and, at the right pace and distance, it is just as beneficial.
For the more motivated, here are some of the standards set forth by the US Army:
Army Ranger Performance Standards
Pushups – 49 to 80 (in 2 minutes)
Situps – 59 to 80 (in 2 minutes)
Two mile – 15:12 to Sub 13:00
5 mile – 40:00 to 35:00
16 mile hike w. 65lb pack – 5hr20min to 4 to 5 hours
15 meter swim with gear – pass/fail
Top End Ranger:
*100 situps in 2minutes
*100 pushups in 2minutes
*2 miles in 12 to 14minutes