Exercise really is a wonder drug. The best of the best!
If only doctors could prescribe it and have people adhere to the prescription.
If only American culture weren't so car-centric and our daily lives involved some natural amount of exercising. We've built a society where only the privileged few can walk or bike to work. It's just too easy these days to barely move in our normal life. Drive to work, drive to the store, drive the kids places... you literally have to specifically schedule exercise (and ironically, many people will drive to the gym to walk on a treadmill).
There are simple things that add up:
Skip the elevator and take the stairs.
Park at the far end of the parking lot, not next to the door.
When I run errands, I park at a central location and walk to the various destinations.
When I meet a friend or associate, instead of meeting at a restaurant, I propose meeting at a nice area and have a walk & talk.
It adds up.