Think you need to sweat for an hour for it to count? That’s the old way of thinking. These days, more and more people are doing tougher, quicker workouts—and seeing similar benefits. Studies have shown that 20 minutes of high-intensity interval training (HIIT) can result in the same amount of weight loss as 60 minutes of moderate exercise. And it just so happens they’re also a lot easier to fit into your busy life.
“The number one reason why people don’t exercise is a lack of time,” says Jason Karp, PhD, running coach and author of 14-Minute Metabolic Workouts: The Fastest, Most Effective Way to Lose Weight and Get Fit (Skyhorse Publishing, 2017). “Is 14 minutes all you need? It is, if you do it right. But it does mean you’re going to have to push yourself.”
Below are three workouts designed by Dr. Karp to improve your cardiovascular and muscular strength. In addition to the 14 minutes it takes to complete the workout, Dr. Karp recommends a 10-minute warm-up to get your muscles ready (a slow jog will do), plus five minutes to cool down. That’s less than half an hour to get fit, fast. Ready, set, go!
Workout #1: Aerobic Tempo 3×4
Choose your favorite type of cardio exercise (running, cycling, rowing, swimming) and alternate hard efforts with easy ones. The hard efforts should feel like a 7 or 8 on a rate of perceived exertion scale (RPE) of 1 to 10, and you should reach about 80 to 85 percent of your maximum heart rate during the interval.
| Duration | RPE | Intensity | |
| Rep #1 | 4:00 | 7-8 | 80–85% max HR |
| Recovery | 1:00 | 2-3 | |
| Rep #2 | 4:00 | 7-8 | 80–85% max HR |
| Recovery | 1:00 | 2-3 | |
| Rep #3 | 4:00 | 7-8 | 80–85% max HR |
| Total time | 14:00 |
Workout #2: Treadmill Hill Pyramid
For this treadmill workout, you’ll need two speeds: one for each rep and one for each recovery period. The only variable that will change is the incline (grade). It will go from a low of 2% to a high of 8% during the reps, and back down to 0% during the recovery stages. During the recovery intervals, you should still be moving at a slow jog.
| Duration | Grade | RPE | Intensity | |
| Rep #1 | 1:00 | 2% | 8 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #2 | 1:00 | 4% | 8 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #3 | 1:00 | 6% | 8.5 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #4 | 1:00 | 8% | 9 | >90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #5 | 1:00 | 6% | 8.5 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #6 | 1:00 | 4% | 8 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Rep #7 | 1:00 | 2% | 8 | 85-90% max HR |
| Recovery | 1:00 | 0% | 2-3 | |
| Total time | 14:00 |
Workout #3: Sprint/Body Weight Circuit
Alternate 30 seconds of sprinting (which can be done outdoors as a run or indoors as fast cycling on a stationary bicycle) with strength training moves. Move quickly from one exercise to the next. Try to complete two circuits, with a two-minute rest between them. (The exercises that are not self-explanatory are described below the workout.)
| Exercise | Duration/reps |
| Sprint | :30 |
| Squat jumps | 10-15 |
| Push-ups | 10-15 |
| Pike crunches* | 10-15 |
| Sprint | :30 |
| Squat side steps | 10-15 each side |
| Superman** | 10-15 |
| V-sit*** | 10-15 |
| Sprint | :30 |
| Mountain climbers | 10-15 each leg |
| Triceps dips | 10-15 |
| Russian twists**** | 10-15 |
* Pike Crunches: Lie on your back on the ground with your arms outstretched above your head and legs straight. In one smooth motion, crunch up and lift your torso off the ground while lifting both legs. Your arms and legs will meet in the middle in a pike position. Slowly lower your torso and legs back down to the starting position and repeat for the prescribed number of reps.
** Superman: Lie facedown on the ground, legs together and straight, and arms straight and extended above your head. Simultaneously raise your arms, chest, and legs off the floor and hold for two seconds. Slowly lower your arms, chest, and legs back down to the starting position and repeat for the prescribed number of reps.
***V-Sit: Sit on the ground with your legs raised up, knees bent. Lean back while simultaneously straightening and lowering legs to create a V shape (your hips should be the point of the V as you balance on your buttocks). Repeat for the prescribed number of reps.
****Russian Twists: Sit on the ground with your legs bent and feet anchored under an immovable object. Lean your torso back so that it creates a V shape with your thighs. Hold your arms extended in front of you with your hands clasped. Twist your torso as far as you can to your right side. Hold this position for a brief moment and then twist your torso to your left side. Continue to twist back and forth for the prescribed number of reps.
This information is for educational purposes only and is not intended as a substitute for medical diagnosis or treatment. You should not use this information to diagnose or treat a health problem or condition. Always check with your doctor before changing your diet, altering your sleep habits, taking supplements, or starting a new fitness routine.
Gabi Redford
Gabi Redford is an award-winning health and fitness writer in Annapolis, Maryland. An avid open water swimmer and triathlete, she is a four-time All American triathlete and three-time qualifier for the ITU World Championships as a member of Team USA.