Interesting topic. The value of exercise is invaluable from someone who knows! When I was diagnosed with tongue cancer and was going through all the treatments, I stayed active with a physical fitness program. Granted there were some days my workout was being able to walk from my bed to the front door and back, but it was a positive accomplishment. Then when the treatments were over and my strength was coming back as well as my mental attitude, I began to exercise with more intensity.

It makes a huge difference how you feel physically and mentally. Plus it is something that you can control. The endorphins get pumping and your attitude does improve. I give you a sense of accomplishment.

The biggest blow to my mental health came when due to all the radiation, I lost the use of my voice! Bummer... Not being able to talk was unimaginable.
Again, my salvation was exercise. It was one thing that I could control and did not have to talk while doing it. Lifting, biking, running, canoeing ... all activities that did not require talking, could be done alone or with other people.

Eventually, not talking made me realize many attributes a person has and many opportunities one has even without a voice. The situation caused me to build a website for the voiceless community, professionals and "victims."
Exercise has been the key to keeping my head on straight and believing less in hope and more in expectations.