Human minds just are not built to consistently do things they don't enjoy, especially if the payoff is very far away. So instead of trying to convince people to do boring, tedious, or not very pleasurable things "for their health", we should look at ways to trick ourselves into thinking we are doing fun or yummy things! One tip: "sightseeing" is more fun than "exercise".

And walking with someone you like is more fun than walking alone on a treadmill.

Watching movies while on a treadmill works.  Skimboarding is probably the best exercise. You are running in soft sand, in an explosive manner, you have to use bizarre, highly under-utilized muscles that require you to maintain your core balance, and it's followed by a brief and enjoyable "reward" and then getting clobbered in ways that require excellent lung capacity.

Heh heh, that's cool to watch but too advanced for me!

why not make more of your life about having fun?  seems like it helps all around (fitness, mental, anti-cancer, etc.) hooray for a joyful life

Just as long as you leave room for the important unfun activities.