Shorter, high-intensity workouts offer the same benefits as longer, moderate ones — here’s how to get started and how it could transform your body

You can get in a great high intensity interval circuit with a heavy bag.

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You can get in a great high intensity interval circuit with a heavy bag.
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  • High-intensity workouts are some of the best ways to improve health and athletic performance.
  • With a short, intense interval workout, researchers have found that some people see benefits equal to or better than those from conventional exercise routines.
  • Here’s how to get started.

If you want to make the most of a short span of time for working out, consider a high-intensity workout.

With brief bouts of high-intensity interval training, it’s possible to achieve or even exceed the physical benefits that people get from spending much longer periods of time working out.

“Time is everything for people,” Jason Barone, a clinical director at an organization called Professional Physical Therapy, previously told Business Insider. “High-intensity training is kind of perfect for the busy schedule – you don’t need a gym, you can do it at your home, you’re looking at about a 20- to 30-minute workout.”

When Barone and other trainers talk about high-intensity workouts, a number of activities qualify. The basic idea is that people work out at close to full-on intensity for short periods of time instead of doing longer workouts at more moderate, 50-70% exertion levels. Some of these workouts include short sprints, some involve circuits of body-weight exercises, and others use weights or kettlebells.

High-intensity training is not always better than a more traditional exercise routine. There are good reasons to do longer workouts – they can help your body adapt to achieve certain fitness goals, such as preparing your joints and muscles for the strain of a long race like a marathon. But intense workouts are often the best way for athletes to improve performance.

They can have powerful effects on health too, helping people rev up metabolism to burn fat, lower blood pressure, and more.

Here’s why you might want to give high-intensity training a try – and what you can do to get started.


Even extremely small amounts of all-out effort — just one minute — can have powerful effects on overall fitness.

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In one small study published in 2016, researchers had a group of men do workouts consisting of three 20-second bursts of all-out exertion, with some warm-up, cool-down, and rest in between sets. The results suggested those participants’ fitness levels improved as much as those of men who worked out for 45 minutes at moderate intensity.

Both groups showed almost a 20% gain in one measurement of the body’s ability to use oxygen – called VO2 peak – which the authors use to represent cardiorespiratory fitness. There was also a dramatic improvement in how all participants’ bodies handled blood sugar. The men in both groups also had a dramatically increased mitochondrial count in their muscles, a sign of good cellular function.

The difference is that one group got their workouts done much more quickly.


Muscles respond to sprint intervals in the same way they do to longer workouts.

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A fitness instructor leads a SoulCycle class at their Union Square location in New York, April 13, 2011.
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REUTERS/Shannon Stapleton

One recent small study published in the American Journal of Physiology had eight young adults complete three cycling workouts in a randomized order over the period of three weeks.

One was a moderate intensity cycle at about 50% of maximum effort for 30 minutes; the second involved going at 75% of max effort for four minutes at a time four times, with one minute rest between each; and the third workout included four 30-second, all-out sprints, with a four-and-a-half minute break after each.

Muscle biopsies before and after each workout showed similar responses – in each case, their cells reacted in a similar way, indicating that the muscle strengthening efforts of each workout were similar, even if one involved only two minutes of all-out effort.


Various studies have shown that high-intensity interval workouts can lead to big improvements in blood-sugar levels.

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One review of research found that people who start doing high-intensity workout programs can improve insulin sensitivity by 23-58%. The studies analyzed in that review ranged from two to 16 weeks long.

Insulin sensitivity helps people’s bodies regulate blood sugar levels. Researchers think high-intensity training plays a role because the regimen improves the ability of muscles to take up glucose from blood so those muscles can be ready to jump into action.


High-intensity workouts might be the best way to improve blood pressure.

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Several studies have found that after 12 to 16 weeks of high-intensity training programs, people at risk of hypertension showed significant improvements in arterial stiffness (which leads to high blood pressure).

These high-intensity programs were more effective for improving that stiffness than conventional exercise routines.


High-intensity training is one of the most important ways to improve athletic performance.

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Whenever you look at a training program designed to help someone become faster, stronger, or a better performer in a certain sport, that program will almost certainly include sets of high-intensity intervals.

That’s because these sorts of programs push people’s limits, which is what you need to do to improve at a sport.

High-intensity interval workouts are much more effective than pure endurance training at improving VO2Max (that commonly used measure of how well muscles use oxygen). Even people who don’t improve much with traditional exercise programs often see significant improvements after doing interval training.


To get started with a high-intensity training program, Barone recommends picking a type of workout that you’re interested in.

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On a basic level, any high-intensity interval program involves a warm up, followed by a few cycles of intense activity with short rest breaks in between.

That activity could be sprinting, swimming, cycling, or do body-weight exercises.

Researchers have studied bursts of activity as short as 20 seconds at a time, but most studies have people go at full intensity for between one and four minutes before they take a short break. Then they repeat the cycle.


There are plenty of pre-designed interval workout programs you could try.

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Several routines that we’ve found effective include body-weight exercises using the the 7-Minute Workout app or the Sworkit app.

You can also try this study-backed 10-minute routine, which includes just one minute of all-out exercise. Other routines involve more strength training.


You can even do a form high intensity interval training for weight lifting or strength training.

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A recent study by the American Council on Exercise (ACE) found that it’s possible to apply the high-intensity interval framework to strength training, too.

When researchers had a group of people start strength training, they assigned them to three groups: one that would do a traditional weight-training program that built up weight slowly, a control group that wouldn’t work out, and a group that would do far fewer repetitions of each exercise than the traditional group, but all at maximum effort.

The group that did the max-effort workouts spent far less time in the gym, but they got stronger faster and stronger overall.


Don’t push yourself too hard during your first high-intensity workout.

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Barone recommends that if you’re doing a new type of activity, you start at a beginner level. This is especially true if you are trying to get back into shape but haven’t been working out regularly. Don’t pick something that’s too complicated for you to do with proper form or technique. Start simple and work your way up to harder programs to avoid injuring yourself.


Warm up properly.

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When going all-out, there’s a chance you could injure yourself if you aren’t warmed up. And that doesn’t mean quickly stretching and touching your toes, either.

Barone suggests doing a five-minute dynamic warmup that will help get your muscles ready to go. When warming up and stretching, focus on the muscles you’re going to use – your shoulders don’t need much attention if you’re going to be sprinting, for example, and your back shouldn’t get neglected if you’ll be swimming.


Listen to your body.

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While high-intensity training by definition means you have to push yourself, make sure you don’t put yourself out of commission and miss your next workout. Try to complete every exercise with the best form you can.

“It’s good to push the body, but you need to listen to it as well,” Barone said. “Be aware of warning signs … don’t push through pain, that might mean you need to take it easy.”

If you feel a sharp or sudden twinge, stop and assess the situation before you continue.


Repeat.

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High-intensity workouts can yield great benefits if you do them several times a week, perhaps balanced in between other longer workouts.

But the best form of exercise is one you can do regularly. If you find a routine you like enough to do on a consistent basis, that’s the way to see the most improvement over time.