I’m out of breath in a hotel room.For the past 13 minutes, I’ve been doing jumping jacks, push-ups and squats, guided along by my iPhone. I feel terrific, and thrilled that I got a decent workout before starting my day out in the real world.

Welcome to the 7 Minute Workout app. There are many of them, including The 7 Minute Workout, 7 Minute Workout Challenge, The 7 Minute Workout with High Intensity Interval Challenge and the Johnson & Johnson Official 7 Minute Workout. Take a look at the featured apps these days on iTunes, Google Play or the Windows Phone app store and you’ll notice several offerings for 7 Minute apps. (It is “New Year, New You” time, after all.)

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The apps promise to cut the typical 30- to 60-minute workout down to a bite-size one. And best of all, the apps are free.

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Experts do say the most effective workouts are those 30 minutes or more in length. But if you’re crunched for time — like I was in the hotel room — and these apps can get you up to high intensity before starting the day, I say great.

For these apps, all you need to get started is a wall, a chair and some floor space.

Most of them have 12 classic exercises to perform — along with some optional extras.

The Johnson & Johnson 7 Minute Workout (iOS, Android), for instance, includes jumping jacks, crunches, squats, lunges and push-ups. It also stretches the seven minutes by offering an optional three-minute warm-up and three-minute cool-down with stretching exercises. (Hence, my 13 minutes with the app.)

The app offers visual clues for how to do the exercise, plus an announcer who takes the place of a trainer, to cue you and keep you in shape.

(This is vital — you’re on the floor, smartphone or tablet by your side, watching the screen to make sure you’re doing it correctly.)

Once done, you click a slider for motivation — this tells the trainer how much he should bark at you.

The other 7 Minute apps are surprisingly similar — a host of exercises and visual clues to perform them.

The main difference between a 7 Minute workout and what you’ll get at the gym? No breaks between exercises. It’s a full seven minutes without stopping.

Now, if seven minutes is too much time to devote to exercise, you might want to give Hot5 a try. The app, from the folks who make the MyFitnessPal calorie-counting app, has 25 exercises to choose from. The idea is that you select a few to do in five minutes, and import the results directly into MyFitnessPal.

Bottom line: You can’t lose for getting out of your chair. So as we try to make good on our New Year’s resolutions, here’s a free way to go for it. And since you don’t have to get dressed and out the door to the gym, maybe you’re more likely to actually do it.

Readers: What do you think of the 7 Minute apps? Is that enough time to get an effective workout? Let’s chat about it on Twitter, where I’m @jeffersongraham.