Q: Sometimes I only have 20 minutes for a workout. What are the most efficient exercises to make the best use of my time?
One of the biggest barriers to establishing a regular workout routine is a lack of time. Finding an extra hour (or more if you include travel to a gym) to exercise most days of the week can feel like an insurmountable challenge, especially if you have a busy work schedule, family responsibilities or a long commute.
The good news is you can get the same (or even better) results from an intense 20-minute workout as you can from a one-hour session.
A large study from 2019, for instance, found that replacing 30 minutes of sitting each day with moderate to vigorous physical activity was associated with a 45 percent reduction in mortality risk. And many studies have found that short, intense workouts two to three times a week can improve lung function and cardiovascular health.
Experts from the Centers for Disease Control and Prevention recommend that most adults get 150 minutes of moderate-intensity exercise each week, but you can cut that in half, to 75 minutes a week, if the workout is intense.
Stephen J. Carter, a cardiovascular physiologist at the Indiana University Bloomington School of Public Health, said that shorter, more intense workouts are better than longer, less intense workouts at lowering the risk of cardiovascular disease and reducing overall mortality rates.
“People really can glean a lot of favorable benefits in a short amount of time,” Dr. Carter said.
How can you get an effective workout in 20 minutes?
Maillard Howell, head of fitness at Reebok and co-owner of Dean CrossFit in Brooklyn, said the key to getting an effective workout in a short amount of time is focusing on compound exercises.
A compound exercise is one that uses multiple muscle groups at the same time to perform a movement — like squats, push-ups or deadlifts. Isolation exercises, like bicep curls or calf raises, won’t raise your heart rate as quickly as compound exercises and primarily work one muscle group at a time.
If you’re short on time, “you want big movements that use big muscles,” Mr. Howell said.
When you use multiple muscle groups, your body shunts blood away from organs to the working muscles, Dr. Carter said, which ultimately raises your heart rate.
Taxing your heart like this two or three times a week can bring a host of cardiovascular benefits, Dr. Carter said, including a decreased heart rate (a sign of a healthy heart) and lower blood pressure.
In addition to compound movements, the other secret to making a short workout effective is minimizing rest time between exercise reps and when transitioning between movements, Mr. Howell said. While you don’t want to rush through an exercise and risk poor form, you also don’t want to stop moving and take a five-minute break in the middle of your workout.
“I don’t need you to go faster, just don’t slow down,” Mr. Howell said.
How should you prepare for your workout?
With any workout, Mr. Howell said that it’s essential to start with a warm-up and end with a cool down. But for a 20-minute workout, your warm-up will have to be efficient.
“You don’t want to spend 15 minutes warming up,” Dr. Carter said. “That means that you’re going to have to to take the warm-up seriously.”
He recommended a three- to five-minute warm-up with the goal of increasing your circulation. “I keep it dynamic. I just want to start moving, and I’m a big fan of raising your body temperature before a workout,” Mr. Howell said.
He likes to do the cat-cow yoga pose, where you start on all fours and arch your back and look up at the ceiling, then round your back, dropping your head between your shoulders. Repeat this movement about 15 times, until your body starts to feel looser, then move onto some jumping jacks and high knees, where you bring your knees up to your chest one at a time, either by marching or running in place.
What should your workout be?
One of Mr. Howell’s favorite full-body, no-equipment, time-efficient workouts is simple and can be scaled to any fitness level or ability.
The workout is: Five body weight squats, five push-ups and a 30-second plank — repeated six times, resting for no more than 30 seconds between rounds. If you can’t do a push-up on the floor, do it against a countertop or a stable bench. You can modify the plank by putting your knees on the floor or doing a standing plank by placing your forearms on the wall.
If this is easy for you, Mr. Howell said, you can ramp up the intensity by trying 10 squats, 10 push-ups and a 60-second plank — repeated 10 times. If you have access to a dumbbell or kettlebell, Mr. Howell suggested throwing them into the mix. You can change the body weight squats to goblet squats, holding a kettlebell or dumbbell in both hands at chest level as you squat. Set a timer for 20 minutes and try doing 15 goblet squats, 15 kettlebell or dumbbell swings and five minutes of running on the treadmill (or around the block) at a moderate pace. Repeat this routine until the 20 minutes are up.
One of Dr. Carter’s favorite high-intensity exercises is a squat to an overhead dumbbell press, which involves holding dumbbells at your shoulders when you descend into the squat, then pressing the dumbbells overhead as you stand.
“It’s a pretty wicked workout,” Dr. Carter said, “and people can squat down to a level they find comfortable and use modest weights.”
How should you end your workout?
Once you’ve completed the workout — and caught your breath — Mr. Howell suggested a three- to four-minute cool down. He recommended static floor stretches, like the pigeon pose — with one leg stretched out straight behind you, and the other leg bent in front with the side of your calf resting on the ground. You can rest your calf up on a bench to make it easier, or just go through any stretches that feel good.
Remember to keep challenging yourself after you grow stronger and improve your cardiovascular fitness. After a few weeks, try a slightly heavier weight, more repetitions or perhaps a more challenging version of the movement.
“You’re not going to get all the good stuff that comes from exercising if you keep doing the same thing at the same weight all the time,” Mr. Howell said, “so start playing around with maybe something a little heavier and go from there.”