As I know DHV by health is better observed than learned or told, but during winter it is much more difficult to show off a nice body. Are there any other ways to DHV by health? Is inviting her to play a sport a good way?
Thanks

A rich man has no need to say he is rich. That would be an actual DLV because he feel the need to qualify himself.

Unfortunately no, it is not the season for flashing your sixpack. And you shouldn't focus on forcing situations where she will notice how fit you are. What you could do is, focus on HER body, and what lies beneath HER winter clothes instead of your own, be curious about her body, and it allows for her to be curious about yours.

And about asking her out to play sports. I wouldn't recommend if you planning on taking her to play something you're really good at, in order to DHV. The purpose of the date is not to DHV, but to enjoy it and have fun. If you enjoy it and have fun, she mostlikely will too.
Tell her it would be so fun to go out swimming together, like kids do. It's childish, fun, you get to look at her body and vice versa.

Hope it helped, goodluck.