The One-Minute Workout: Science Shows a Way to Get Fit That's Smarter, Faster, Shorter

by Martin Gibala

traditional exercise training involves traveling a certain distance at a relatively constant pace.

That sort of training has a lot of therapeutic benefits. It reduces stress and can provide the opportunity to enjoy the outdoors. But my research has shown that it is anything but the most efficient way to train.

If time is our most valuable resource, and if we’re attempting to get the most benefit from exercise in the least amount of time, then, as my research has shown, we’re better off employing interval-training techniques.

The idea is to vary the intensity of your workout. Go hard, relax, go hard, relax. The harder you go, the shorter the duration and the fewer intervals you need to achieve the same benefits of a much longer endurance-training workout.

More recently, the prestigious academic journal Cell published a study about a compound, known by the acronym AICAR, that helped sedentary mice run for 44 percent farther than untreated mice. The study raised a flurry of excitement about the possibility of developing an exercise pill, yet no one’s been able to replicate the results in humans.

A. J. Jacobs wrote in Esquire, “HIIT could be the biggest time-saver since microwaves.”

Again, that’s nonsense. Workouts don’t have to last an hour. They can last ten minutes or even less—and get you remarkable fitness benefits in that time.

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.

So how do you build aerobic fitness? For a long time, many coaches and athletes thought that becoming aerobically fit required an enormous amount of exercise performed at a moderate pace.

the body has two main ways of powering movement. It draws mostly on the anaerobic system when it requires lots of power, as when lifting heavy weights or all-out sprinting. And it mainly draws on the aerobic system when it performs less-intense movements for longer bouts of time, like jogging or cycling long distances.

But the essential message is the same: as you repeat the basic pattern of sprint, rest, sprint, rest, a greater proportion of the energy comes from aerobic metabolism.

1973 study of Swedish military recruits by one of my mentors, the legendary Scandinavian physiologist Bengt Saltin, concluded that physical fitness could be rapidly improved by interval training despite a short time investment.

The Japanese researcher Izumi Tabata showed in 1996 that training using brief, intense intervals could substantially improve cardiorespiratory fitness.

Two years later, my master’s thesis adviser at McMaster, Duncan MacDougall, showed that training in short, hard intervals could dramatically increase the amount of mitochondria in muscles, the cell...

The experiment we designed looked at whether a handful of sprints could improve endurance performance. It worked like this: We assessed how long the subjects could pedal a stationary bicycle set to a fixed workload. Then the subjects went off and conducted six training sessions over two weeks.

The six training sessions conducted by the subjects required them to sprint on a stationary bicycle. The specific protocol is known as a Wingate test (named after the Israeli sports institute where it was developed, the Wingate Institute), which is designed to measure someone’s anaerobic power—the all-out explosive effort necessary to bike, skate, run, or swim as fast as possible.

Wingates can be helpful. “If you’ve never done the Wingate-cycle test, let me try to explain what it feels like,” A. J. Jacobs wrote in his Esquire article about interval training. “It feels like your legs are giving birth. It feels like you’ve got an eight-martini hangover in your calves. Your face contorts like a porn star in an AVN-award-winning threesome scene. You emit noises that resemble feedback at a thrash-metal concert. . . . The upside: It’s over in 30 seconds.” Jacobs is exaggerating just a little about how painful Wingates are. But his greater point is sound. You’re supposed to give it your all.

As the results came in, it was difficult to maintain that façade of impartiality. The numbers were crazy. The sprinters had doubled their endurance times. On average, before the training, the eight subjects could pedal the bike for twenty-six minutes until exhaustion. Following the six sessions of interval training, the average time was fifty-one minutes. It was an amazing result.

more mitochondria mean you can generate aerobic energy more quickly and with less fatigue.

In short, the experiment showed that approximately ten minutes of hard exercise a week boosted overall fitness to the same extent as four and a half hours per week of traditional endurance training. It’s mind-blowing. A tiny bit of sprint training has the same effect on the human body as a whole lot of endurance training—despite a much lower training volume and time commitment.

Under strictly controlled conditions, in experiments that have been published in the most reputable peer-reviewed physiology journals, my lab and others around the world have shown that small amounts of interval training can produce benefits we usually associate with large amounts of endurance training. The harder and faster you go, the less time your exercise requires. Go as hard as you can in short bursts, and you can get the benefits of an endurance exercise regimen with less than 5 percent of the time spent in hard exercise, 10 percent of the work expended, and only one-third of the total workout time commitment. To

One important aspect of fitness is the ability of your heart and lungs to pump blood and oxygen throughout your body. This is what most people mean when they talk about “cardio” fitness.

Another component of fitness is the ability of your muscles to use the oxygen that gets delivered.

Muscles use oxygen to burn fuels, such as sugars and fats, in a complex process that yields the energy-laden molecule known...

Muscles store only a small amount of ATP. It’s a relatively heavy molecule and therefore just not efficient to keep on hand in large quantities.

One convenient form of energy is a molecule called phosphocreatine. Think of this molecule as dollar bills in your wallet. Phosphocreatine is easy to convert, but you tend not to keep it in large quantities. It’s used to immediately resupply ATP when your muscle starts to contract. Phosphocreatine fuels the lion’s share of the energy during your first few seconds of sprinting. This process is extremely fast, but the capacity is very limited.

Another process that can supply ATP relatively quickly is anaerobic glycolysis, which involves the partial breakdown of sugars stored in muscle. You can think of these as the fives in your wallet. The process is quick but rather inefficient, and can get bogged down by the formation of metabolic by-products. The classic by-product is lactic acid, which accumulates in the muscles of sprinters and is part of the reason why they eventually slow down during a race.

By far, the most efficient way to supply energy is through a process called oxidative metabolism, which involves the use of oxygen to burn fuels such as sugars and fats—the large-denomination bills in your wallet. While slower than the other two processes, oxidative metabolism provides the capacity to utilize many different fuels. The other nice thing about it is that, given adequate fuel availability, the capacity is almost limitless.

To summarize, the key to aerobic metabolism is all about getting oxygen and fuel to the mitochondria in the muscles. This

Endurance exercise typically refers to long-duration, low- to moderate-intensity activity that increases the body’s ability to use oxygen to produce energy for sustained movement.

A physician named Hans Selye in the 1930s developed a theory about the way the body responds when stressed. Selye’s general adaptation syndrome says that the body responds in a manner intended to reduce the stress the next time we experience it.

Then, once the stressor is gone and the body is recovering, the body adapts so that the next time the same stressor presents itself, it disturbs the body to a lesser degree.

AMP in particular triggers the activation of a protein with the unwieldy name of 5’-adenosine monophosphate-activated protein kinase, or AMPK. In turn, AMPK activates a protein called—bear with me here, because it, too, is a mouthful—peroxisome proliferator-activated receptor gamma coactivator-1alpha, which most physiologists refer to by its short form, PGC-1α—that last symbol is pronounced “alpha.”

Some scientists also believe that PGC-1α helps stave off age-related muscle decay.

The bottom line for our purposes is that PGC-1α is a key signal that triggers skeletal muscle remodeling, allowing the body to perform exercise for longer than it did before.

That year, we submitted a study to the Journal of Physiology in which sixteen college-age students performed six training sessions over two weeks. In each training session, half the subjects cycled continuously for 90 to 120 minutes at a moderate-intensity pace. The other eight subjects performed four to six 30-second sprints at an all-out pace, separated by 4 minutes of recovery. The endurance training group’s total time commitment was 10.5 hours over the two-week period. In contrast, the total training commitment for the sprint group was about 2.5 hours, including the recovery periods—although the total amount of hard exercise for the sprint group was just 18 minutes. Once the two weeks were up, testing revealed that the two groups had improved to a virtually identical extent in every measure we tested. Both groups improved their cycling time-trial performance by the same amount and also demonstrated remarkably similar changes in the molecular makeup of their muscles. Considering the difference in the amount of time the two groups trained, it was an incredible result. A total of just 18 minutes of very intense exercise produced the same benefits as 10.5 hours of traditional endurance training.

Sean McGee, who was an expert at analyzing the molecular changes that exercise prompted.

Muscle fibers

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relatively easy m...

moderate-intensity enduranc...

Ty...

fast-...

powerful mo...

high-intensity ...

recruits type I muscle fibers and the larger ...

trigger training adaptations.

exercise snacking—breaking a workout into multiple chunks spread throughout a day.

six hard reps of minute-long incline walking.