"Wired to run, meaning that our brains are probably, have been sort of rewired from an evolutionary sense to encourage these running and high aerobic-activity behaviors," Raichlen said. Several anthropologists believe the same as Raichlen and that humans learned to run long distances from chasing their prey down.
Raichlen decided to test his theory and conducted an experiment using dogs and ferrets. The dogs experienced the high and the ferrets did not. This concluded that this level of exercise was encouraged by natural selection and is in our evolutionary roots. The high runner's or dogs get from this level of exercise is a body produced drug named cannabinoids which are the same chemicals in marijuana.
I completely believe Raichlen's theory because I'm a rower and it is an intense aerobic sport and to condition we spend a lot of time running long distances. If i go three days without exercise, I find myself freaking out and feeling lazy and lethargic. I call these my exercise withdrawls and I just "have" to run or some form aerobics or I will not be a happy person. Finishing a long intense row or run, has the best feeling ever. Sure your legs are on fire with pain, but the accomplishment and every breath you've taken you know you succeeded. What can beat that feeling?
I'm pretty sure my body has produced that drug as well as in any other rowers on my team. We're addicted to rowing and the high we get from it.
