There's few other negative responses to your comment, but there's plenty of research linking physical fitness with mental improvement. I recently went from morbidly obese to quite fit and even as a younger person I noticed a significant improvement in my cognitive abilities. I'm just less tired, less foggy, able to think for longer periods of time with less fatigue. It's been quite a nice side benefit.

Of course some people are unable to remain fit, but many more simply choose not to prioritize it. I suspect it the vitality you demonstrate helps sell your "brand", and also just helps you to be better than you would be otherwise.