If you had played some other VR games you'd already know that plenty of VR games feel like exercise and make you break a sweat, without needing a fancy treadmill hardware. Simply out of the fact that you are moving around a lot.
Space Pirate Trainer and Thrill of the Fight are two of the more intense games that come to mind.
i'd be satisfied with a boxing game cross-platform. I have the full PSVR suite complete with 2 motion controls. It's no Vive but it does the job for far far cheaper. So, controls in hand, I'd box my way to a championship and a rock hard bod and enjoy every minute.
Still not on board with VR. About the only use I see is it will let you instinctively look around the cockpit in a racing/flying game.
I think it is a fad, just like 3D.