Whoever said slow and steady wins the race didn’t have a full-time job, a slowing metabolism, and an endless to-do list. When it comes to staying in shape on a tight schedule, there’s no fairy tale solution, but there might just be a practical one: interval training.

Research suggests that by alternating bursts of high and low intensity activity, interval training can super-charge fat-burning, boost metabolism, and improve cardiovascular fitness [1] [2]. These dynamic workouts require no fancy equipment and can clock in at just 15 minutes a pop (consider how long we spend hitting the snooze button every morning). Intervals are also ideal for keeping workouts fun and varied and, since speed and resistance can be easily adjusted to meet any skill level, they’re very newbie-friendly.

Sound too good to be true? The Greatist team zipped over to Crunch Fitness — Union Square, where Master Trainer Jennifer Cassetty invited us to test three interval workouts, each tailored to fit our testers’ varying fitness levels. Read on to get some programs, takeaways, and tips on revving things up with intervals.

Beginner Program

[4-minute warm-up]
2-minute walk 
2-minute jog
1-minute run 
Repeat 3 times through
[5-minute cool-down and stretch]

What our Greatist tester, David, had to say: “I don't run often (read: almost never), and while I enjoyed the program, I had a bit of trouble adjusting my stride to fit the different paces.” What David recommends: “Start small and work your way up. I felt great even though the runners next to me absolutely smoked my workout. It was an awesome feeling afterwards. I definitely got a good workout.”

Intermediate Program

[5-minute warm-up]
30-second walk
1-minute sprint 
1-minute incline lunges on the treadmill
Repeat 6 times through
[5-minute cool-down and stretch]

What our Greatist tester, Leah, had to say: “As a distance runner, I usually just set the timer on the treadmill and go. With interval workouts, you need to pay attention to the clock the entire time, especially when the intervals are short.” But the time flew by, Leah said, and she liked being in control of her speed and incline: “It’s a great way to track your progress.”

Advanced Program

[5-minute warm-up]
1-minute sprint, 1-minute jog
2-minute sprint, 1-minute jog
3-minute sprint, 1-minute jog
2-minute sprint, 1-minute jog
1-minute sprint
[5-minute cool-down and stretch]

What our Greatist tester, Derek, had to say: “Interval training is fun because there's never enough time to give up. There's always a break coming in just a few seconds, so you can push yourself to the brink knowing there's an opportunity to breathe (literally) afterwards.” Why keep it up? “At least for me, it's an effective way to maximize precious gym time. Plus, when I'm done, I always feel like I've accomplished something instead of just slogged through it.” In a recent post, Derek shares his favorite interval workout.

Tips From Our Expert

Ready to give intervals a try? Consider Cassetty’s quick tips for a safe and effective run:

• Foot Action. Most sneakers are built to last up to 500 miles before the shock-absorbent foam breaks down. Keep feet happy and healthy by replacing them as often as needed (usually after about 6 months).
• Stride Right. A stride that’s too short or too long can lead to repetitive stress injury. How to know what’s just right? When running with the proper stride length, the feet should land directly underneath the body. If the body appears to bounce, take that as a sign the stride is too short.
• Mind the Incline. Hills (artificial or not) can add strain to the knees. For those attempting incline lunges, be sure to take a big enough step forward that the knee stays directly over the heel, which will minimize knee strain.
• Balancing Act. For a 5-day-a-week workout schedule, try intervals for 2 of those days and steady state cardio for the remaining 3. A balanced mix keeps the cardiovascular system working efficiently.
• Mix it up. The beauty of intervals is their built-in variety. If the above programs need a little kick, try adding a lateral shuffle (be careful when trying on the treadmill) in order to work different joints and challenge muscle memory with new movement patterns. Tired of the treadmill? Hop on a bike or an elliptical instead.
• Loosen up. High-intensity exercise demands a proper warm-up, cool-down, and post-run stretch session. Be sure to focus on the main muscle groups worked, holding each stretch for 10 to 15 seconds a side, then repeat.
• Think Big. Intervals are all about progression. Aim for a 10 percent increase each week— whether that’s increased speed, resistance, or duration. “The point is to take you out of your comfort zone, so if you don’t feel like you’re challenged, move on,” Cassetty says.
• Be committed. As with any new workout, patience is key. Some interval converts might see results as quickly as 2 weeks in, while others might need 12. Train hard and take pride in keeping track of your progress!

Share your favorite interval workout tips in the comments below!