HOUSTON -

No machines, no weights. Just seven minutes of your time.

Researchers say if you're crunched for time, they've found the key to changing your body and improving your overall health.

Many people struggle to find the time to get into the gym, but researchers claim this new exercise craze reaps the benefits of hours of running and pumping iron in just seven minutes.

Houstonian Sean Coerve told Local 2, "It's pretty intense!"

It promises maximum results with minimal investment. It's just 12 simple exercises, done in rapid succession, with less than 10 seconds of rest in between.

On a pain scale of one to 10, you should be hovering at an eight.

"The more you do, the more you become accustomed to what you might call pain," said Coerve.

An article published in this month's American College of Sports Medicine's Health and Fitness Journal explains the seven minute High Intensity Circuit Training workout incorporating moves like jumping jacks, push-ups and lunges.

Houston strength and conditioning coach Hayden Cowie with Shape Fitness USA explained why it works. "I think because you go from anaerobic to aerobic and you cross that aerobic threshold, you come back down so you're burning calories at a higher rate," said Cowie. "You're body's really working hard the entire time. It's very intense. It's super intense."

But Cowie said the order in which you do the exercises is just as important.

"Sequencing is key, said Cowie. "You can't burn out smaller muscles and little intrinsic muscles and then try to work the major muscle, because they support it. You have to start with the big muscles and work your way down. It's kind of the trickle effect."

Houstonians who've committed to the workout say they've built muscle, increased endurance and seen noticeable health benefits.

Maria Hammerlein told Local 2, "My cholesterol level is perfect. I have the heart of a 25-year-old and I'm way past that, and I just have a better attitude about life, and it's just the fountain of youth."

Cowie added, "You're not just stronger, but you're stronger longer."

Cowie's class is an hour long and while he believes in the training, he doesn't believe just seven minutes a day is going to cut it.

He explained, "If you play a sport, it's a great to supplement a workout, but I don't recommend anyone put themselves through seven minutes of intensity every day and think that's all they need to do."

Hammerlein added, "I would say stretch it to 30 minutes if you can, but seven is better than nothing."

The authors of the study agree it's better than nothing.

They do say if you have the time, you can repeat the circuit two or three more times.

The Seven-Minute High-Intensity Circuit Training Workout

Perform the following exercises for 30 seconds each with 10 seconds of rest in between. Aim to perform 15 to 20 reps of each exercise within the 30-second span for a total of about seven minutes. Repeat entire circuit two or three more times if needed.

1) Jumping jacks

2) Wall sit

3) Pushup

4) Abdominal crunch

5) Step-up onto chair

6) Squat

7) Triceps dip on chair

8) Plank

9) High knees/running in place