People are complex human beings who experience life on several levels (physical, emotional, mental and spiritual.) Real change work is done on all levels. The results and benefits are experienced in many ways.
In relation to healthy and fitness the benefits can be a new heightened self image. Achieving fitness goals leads to self-confidence, improved body image and discipline.
And as ones health improves it will effect the over all immune system, meaning a better work performance, fewer missed days at work and school etc. Good health can bring a increase in oxygen flow throughout the body especially the brain.
On a physical level health changes reduces the risk of injury.Strengths the heart, lowers blood pressure, assists in anti-aging, digestion, skin, hair etc. Everything depends on circulation and the only way to get things circulating is by moving.
Finally ask a professional athlete if training is a spiritual experience and they will agree. Many people roll their eyes when you start talking about a professional athletics. As if they cannot relate to them. But we can learn alot from a professional. About their thoughts, their attitude etc. And if you apply what we learn to all levels you can experience the benefits on all levels