I've always known that my sedentary lifestyle was killing me, but I never thought it would keep me from playing video games. Valve's SteamVR Developer Showcase proved otherwise, albeit unintentionally. Virtual reality is wholly unlike the so-called "active" games of the last decade.

In Wii Sports, you lazily waggle and swing a remote. With Kinect, you sloppily wave and "dance" to match an on-screen beat. In virtual reality, you just move. If it's an action game, you instinctively dodge a barrage of deadly lasers. You kneel down to hide behind a crate, only to leap up in a squat-jump to shoot at an enemy behind cover. You're not thinking about it, you're just doing what you have to in order to win. Twenty minutes later, and you've put yourself through an intense cardio workout.

That scenario sounds hypothetical, but it isn't -- that's exactly what happened to me last week playing demos for Hover Junkers, Space Pirate Trainer and AudioShield. Although I only spent 15 minutes with each of these games, all of them tricked me into being far more active than I planned. That, I realized, was what made being active in VR so different than playing contemporary motion-controlled games: I was exercising by accident.

Audioshield, for instance, had me blocking rapid-fire abstract missiles to the beat of Metallica's "No Leaf Clover," effectively putting me through short bursts of fast-paced shadow boxing. Hover Junkers forced me to duck behind virtual cover to avoid enemy fire in what amounted to a ten-minute squat routine. At the time, I just thought I was playing a game, but each experience left me gasping for breath. I shamefully realized the truth: I'm too out of shape to play some of the best VR games coming to first-generation headsets. That won't do.

For the first time in my life, video games are about to enact a positive change on my lifestyle. If I want to experience fast-paced action in standing, full-body VR of the kind I saw at Valve's SteamVR showcase, I'm going to need to get into better shape. As an inherently lazy man, I'm not happy about that -- but it's a reality I'm going to have to accept. Now, if you'll excuse me, I have to go for a run. Because I want to play video games later. Man, the future is weird.