After reading this book in June of 2018, I wrote,

 

"The 150-minute-per-week workout is obsolete. Based upon what I learned in this book, I do 5-minutes of high-intensity exercise per week and I'm staying in great shape."

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See all my book recommendations.  

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Here are the selections I made:

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If you count only the intervals—that is, if you total the time our test subjects were required to perform hard exercise, then our sprinters worked out for just under ten minutes a week. Compare that with the other group’s four and a half hours of continuous moderate-intensity exercise per week. The time the sprinters spent exercising amounts to less than 5 percent compared with the endurance group.

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The past decade has seen an explosion of research into the science of high-intensity interval training, better known by its acronym, HIIT, pronounced “hit.”

 

But the fact is, a method exists that enables you to reap the benefits of hours of exercise in just minutes per day.

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HIIT is so popular that it has ranked at or near the top of the annual list of worldwide fitness trends compiled by the American College of Sports Medicine, the largest sports medicine and exercise science organization in the world.

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Fitness means different things to different people. To exercise scientists, it means cardiorespiratory fitness, a parameter that can be measured in the laboratory by way of a test called maximal oxygen uptake or “VO2max” (the “V” stands for “volume”). It is also called aerobic fitness, and it refers to the capacity of your body to transport and utilize oxygen. Scientists have found that it’s one of the best predictors of overall health.

 

The more aerobically fit you are, the better your heart can pump blood, the longer it takes you to get out of breath, and the farther and faster you’re able to bike or run or swim. One more thing: It also happens to be the form of fitness that helps you live longer and live better by reducing your chances of developing ailments like cardiovascular disease and diabetes.

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The problem with these guidelines is that they scare plenty of people away from exercising. Lots of people are actually incredulous about it—it’s like, you want me to work out for two and a half hours a week? Are you crazy? I can barely manage the laundry! And in fact, only 15 to 20 percent of Americans actually meet those fitness guidelines.

 

You hop into the saddle and pedal as hard and as fast as you can for thirty seconds against a high resistance. The idea is to go all out. “Go as hard as you can,” I told the subjects. “As if you’re sprinting to save a child from an oncoming car—go that fast.”

 

doubling of endurance capacity in only six training sessions? With just sixteen minutes of hard exercise? It seemed miraculous.

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We decided to compare our sprint-training program with a strenuous regimen of moderate-intensity endurance training based on the typical physical-activity guidelines. We recruited twenty people and divided them into two groups, with five men and five women in each group.

 

One group was put on a quite rigorous endurance training regimen for six weeks. These subjects rode stationary bicycles five days a week for forty to sixty minutes per day. They cycled at an intensity of 65 percent of their maximal aerobic capacity, which is within the moderate range as recommended in the public health guidelines. The pace was enough to get their heart rate elevated and get them sweating.

 

Now for the interval-training group. They also went on a six-week-long training regimen, but one that required much less work and time. It was modeled after the protocol used in our first study. The subjects began by spending a couple of minutes warming up on the exercise bicycle. Then they performed a thirty-second-long sprint. They rested for four and a half minutes, and then they did another sprint, repeating this four to six times. Instead of training five days per week, they trained three days.

 

If you count only the intervals—that is, if you total the time our test subjects were required to perform hard exercise, then our sprinters worked out for just under ten minutes a week. Compare that with the other group’s four and a half hours of continuous moderate-intensity exercise per week. The time the sprinters spent exercising amounts to less than 5 percent compared with the endurance group.

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How did the results for the two groups compare? Basically, the improvements were the same for every fitness parameter that we measured. That means both groups improved following the training, but we could not detect any significant differences in the extent of the change between the two groups. The increase in aerobic fitness? The same. The increase in mitochondria in the subjects’ muscles? The same. The change in fuel use and, particularly, the subjects’ ability to burn fat during exercise? The same.

 

And if you can tolerate it, a minute’s worth of maximal exercise, in the form of three all-out sprints for twenty seconds each can change your physiology as much as fifty minutes of cycling at a moderate pace. Studies from my lab have demonstrated all these things. The naysayers warn that high-intensity intervals are only for people who are really fit and really motivated. But those naysayers are wrong. Listen: Some people shouldn’t perform interval training. But it’s a rather limited group, and many more—even those with chronic diseases—can benefit from an interval-based approach to fitness.

 

 

Peak Intensity • 10+ Duration • 25 minutes The Evidence • When it comes to boosting fitness, there’s something remarkably potent about going all out—and this is the protocol that helped us grasp that. We based it on repeats of the Wingate test, a 30-second all-out sprint on a stationary bike. It’s exhausting—and remarkably powerful. The training protocol features a series of five 30-second all-out sprints, a total of just 2.5 minutes of hard exercise per day. In our study, we had our subjects repeat the protocol three times a week, amounting to a weekly time commitment of just 1.5 hours, and less than 10 minutes of hard exercise a week. After 6 weeks, we compared the sprint group’s benefits with those experienced by a group that exercised continuously at a moderate intensity five times a week for a total of 4.5 hours a week, also for 6 weeks. The sprint subjects either equaled or exceeded the conventional exercisers in their improvements in aerobic capacity, muscle endurance, and the ability to burn fat. A remarkable result, considering the sprint group spent a third of the time exercising. 

 

A minute of hard exercise. You sprint as hard as you can, for twenty seconds, and then repeat that twice more for a total of three sprints? Congratulations. You’ve just done the most potent workout available. I feel confident saying a minute because we just published a study that showed people who did a minute of all-out exercise three times a week, within a total time commitment of 30 minutes a week, had the same improvement over three months as the people who did all the exercise specified by the public health guidelines. That is, 150 minutes a week of continuous, moderate exercise. Here’s why: Intensity is more important than duration. Relative to all sorts of health benefits, it is more time-efficient to exercise hard for a short amount of time than it is to exercise easy for a long amount of time.

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Next, in an experiment that lasted twice as long, at twelve weeks, we compared a sprint group that did three minutes of hard exercise a week, set into a protocol that lasted thirty minutes a week, with a group that exercised for 150 minutes a week, as recommended by the guidelines. Incredibly, the benefits turned out to be the same.

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In late 2014 we published a study that tracked the benefits of the smallest amount of exercise my lab has tested: three 20-second sprints per day, totaling a minute’s worth of hard exercise per day amid a total per-day time commitment of 10 minutes. Repeated three times in a 7-day period, the protocol amounted to 3 minutes of hard exercise per week. We asked sedentary, overweight, and obese men and women in their twenties and thirties to follow the protocol for 6 weeks and were astonished at the results. Just 3 minutes of intense exercise per week reduced blood pressure by 6 to 8 percent, and elevated cardiorespiratory fitness by 12 percent, translating into a reduced risk of dying and developing chronic illnesses.

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Most remarkably, research we’ve just conducted in my lab tracked the 1-minute-interval protocol’s effects over 12 weeks on sedentary, nonathletic individuals and compared the benefits to those of another group that conducted 135 minutes a week of moderate aerobic exercise. And the benefits were the same. That’s right: It was possible for everyday, nonathletic sedentary individuals to derive the cardiorespiratory benefits of 135 minutes a week of traditional endurance training—three 45-minute sessions per week—with just a single minute’s worth of hard exercise repeated three times per week.

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THE WORKOUT Warm up with some light physical activity for 3 minutes at an easy pace. Blast through a 20-second sprint at an all-out pace. Rest with some light activity at intensity 1 for 2 minutes. Blast through another 20-second sprint. Repeat the cycle until you’ve completed 3 sprints. End with a 2-minute cool-down for a total duration of 10 minutes. Feel free to customize the sprint activity to any full-body movement that significantly elevates your heart rate—such as the stair climbing I mentioned earlier in this chapter. Note that the protocol we tested in the lab featured different warm-up and cool-down times. To bring this workout in line with the others in this book, I’ve used a 3-minute warm-up and a 2-minute cool-down. 

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