There several reasons exercise are beneficial to the body physically and mentally, but unfortunately its not part of our regular culture and health expert have failed to encourage people to exercise. Some of thesd reasons are

1. it reduces stress
2. it helps to fight addictive habit
3. Increases metabolism
4. helps in fighting diseases
5 Sharpens one senses
6. Boost confidence

And many more

http://naijasphere.com/why-you-need-to-exercise/

I highly doubt even the health section moderator exercises. I'm yet to see moderator created health-themed topics here.

About the number 2 - It replaces an addictive habit not fight it.

Also, it strengthens one's body in a way that everyday activities become effortless. Doing an exercise routine daily helps you improve in it and add more hours thereby seeing you become stronger as years pass.

It gives a sexy body.