Comments on the benefits of Savasana from Roger Cole, Yoga Teacher and Scientist. Taken from an interview between Leslie Howard, an Oakland-based yoga teacher and Roger Cole, an accomplished scientist educated at Stanford University and the University of California, with specialties in the science of relaxation, sleep, and circadian rhythms, and a Yoga Teacher.
The value or benefits that come from dedicated practice of Savasana are in part physical and in part mental. In your brain you are always processing impressions—the mind is doing things, observing things, or observing the results of your doing things, or memories are already in the mind while minimizing new input or effort. When you are in Savasana, we actively stop actively working in the world muscularly, and if our mind is set right, we can observe what is in the mind. It’s not that we stop processing—the mind is always going—but it’s going in a way that doesn’t require this executive function in the brain (the part of you that says, now I must do this , now I must do that). It doesn’t involve “I” at all. It’s an egoless watching, and with that I think what happens physiologically is that information gets processed—connections between nerve cells that need to be strengthened, connections that aren’t used much tend to diminish—so we actually change the brain patterns or they change or reorganize themselves.
I like to think of the impression of a forest, an ancient forest. It has been there for so long—holding still for so long—that everything is sort of coming into its own balance without anyone directing it. And so our own mind—if we just leave it alone—will come into its own equilibrium. We stop pushing it around, adding things to it. So a lot of the benefit of Savsasana is allowing the time to for the process to take place.
It's also restful for the body; you give your heart and your muscles a chance to recover. Internal recovery function is analogous to what is happening in the brain—think of cells healing themselves as an information process. The brain is organizing proteins, reestablishing them, getting rid of waste. So it’s a rest period for the body and a reorganization period for the body.
--- taken from the Yoga of Aging website