It’s a commonly-held assumption that getting in shape requires hours and hours of rigorous exercise. But some fitness experts believe all that’s really required to stay physically fit are short burst workouts performed at a high level of intensity. Here’s why just a few minutes of exercise each day may be all you need.

It’s called high-intensity interval training (HIIT) — and it’s proving to be a surprisingly effective way to stay in shape. It sounds almost too good to true, with workouts typically lasting no more than four minutes at a time. But many trainers and practitioners have found that it works. And it’s the kind of thing that can be easily integrated into any busy schedule.


Top image: Christmas Abbott doing a burpee. Abbott is a business owner, a NASCAR pit crew front tire changer, and an avid CrossFitter — a strength-and-conditioning program that integrates high-intensity interval training. Credit: SHFHS.

The trick, of course — and there’s always a caveat to these things — is that these workouts must be executed at high-intensity. That means balls-to-the-wall full exertion. So if if you don't like to get physically intense, then this workout style is probably not for you. What’s more, if you have a workout routine that you love, it’s working for you, and you’re able to stick with it, then by all means continue with that!

HIIT protocols come in many shapes and sizes, but it all got started in the 1990s with the advent of the now-famous Tabata technique.


The Tabata protocol

Back when he was coaching the Japanese Olympic speed skating team, Izumi Tabata, along with his colleague Irisawa Kochi, began studying the effectiveness of a specific training routine — one that involved a rotation of short burst maximum efforts followed by short periods of rest. More specifically, the coaches were looking at a method that consisted of repetitions of 20 seconds of intense work, followed by 10 seconds of rest. Thus, an entire workout could be performed in only four minutes when repeated eight times. Tabata put his skaters through this routine about four to five times per week.


And it worked brilliantly.

As Tabata’s ensuing paper showed, athletes who do this type of interval training experience tremendous benefits in anaerobic capacity. In addition, high-intensity workouts have also been shown to improve overall conditioning, improved glucose metabolism, and improved fat burning.

Why it works

And indeed, the power of HIIT lies in its ability to facilitate fat burning, even once the training is done. Part of this has to do with having an elevated temperature. But it’s also because our bodies can’t bring in enough oxygen during these periods of strenuous exercise, creating a kind of oxygen “deficit.” This results in post-exercise oxygen consumption, or EPOC, and it helps by boosting our metabolism. EPOC is also associated with hormone balancing, replenishment of fuel stores, cellular repair, innervation (the excitation of organs and muscles), and anabolism (when energy is used to construct molecules from smaller clumps).


So, while conventional wisdom tells us that we need to workout for long durations to burn calories, the EPOC effect shows that it’s also the intensity of the exercise that matters. At least in the case of aerobic exercise. The takeaway here is that, if you want to stick to your low-intensity workouts, that’s fine — but you might want to to incorporate quick, intense bursts every now and then.

Tougher than it sounds

Admittedly, four minutes of work does not sound like much. That is, until you try it.


I’ve integrated the Tabata protocol into my own training and I can honestly tell you it’s tough. And it doesn’t matter what kind of shape you’re in or who you are — when you give a total effort for 20 seconds, and you have to repeat that eight times with only 10 second breaks, it starts to burn, and the cardio picks up quickly and appreciably. I find that I’m pretty gassed by the end of it.

Another advantage of the Tabata protocol is that it can be applied to a host of exercise techniques. Personally, my favorite way to do Tabatas is on a stationary rower, but it can also be done by skating, sprinting, bicycling, and so on. All that’s required is that the motion be physically demanding (i.e. an aerobic exercise) and that it be done at absolute full tilt — specifically, a maximal oxygen uptake (VO2max) of about 170%.


HIIT may also result in less wear-and-tear on the body.

It’s also worth noting that the Tabata protocol is not the only one. There’s also the Gibala protocol (60 seconds of work at 95% VO2max with 75 seconds of rest repeated for 8 to 12 cycles) and the Timmons protocol (three 2 minutes bursts of gentle pedalling on a stationary bike followed by 20 seconds of cycling at total effort).

There’s also the 4x4 12-minute per week workout which recently got some press and is worth reviewing.


The 12-minute per week workout

Late last month, researchers from the Norwegian University of Science and Technology published a paper in PLOS ONE showing that only four minutes of vigorous activity three times a week is enough to be fit and healthy.


The purpose of the study was to determine just how much exercise, and how intense that exercise needs to be, to get the most bang for the buck. The key metric used by the researchers, a team led by Arnt Erik Tjønna, was VO2max, and their efforts focused on the optimal way to improve it among normally inactive men.

Tjønna’s team took 24 men who were overweight (but otherwise healthy) and put them through a 10-week training session that involved three weekly high-intensity interval exercises.

The researchers set up two groups, one that consisted of 13 men who performed four intervals of four minutes at high intensity at 90% of maximal heart rate, interspersed with three minutes of active recovery at 70% maximal heart rate (which is known as 4x4 training, a protocol that has previously been shown to be effective). The second group followed a fitness routine that consisted of one 4-minute interval at 90% maximal heart rate.


The group which performed just one high intensity workout each week saw a VO2max increase of 10%, while the 4x4 group experienced a boost of 13%. Both groups saw decreases in blood pressure.

“Our study demonstrated that slightly overweight and healthy individuals only required brief, duration bouts of exercise with good effort three times a week, to produce large increases in VO2max and work economy and reduce blood pressure and fasting glucose levels,” the researchers wrote in their study. “Additional studies to examine both adaptations at the molecular level and feasibility for public health appear warranted.”

So not only are quick and intense workouts advantageous, they don't even need to be that frequent.


Not quite everything the body needs

While HIIT protocols are clearly effective, it’s my personal opinion that they’re not completely adequate to a well-rounded fitness routine. These regimes are biased towards aerobic exercises, typically at the expense of resistance training. As I’ve noted before, integrating strength work into your workouts is critical.


Obviously, it’s possible to do resistance training in conjunction with HIIT. I do CrossFit, so I get my fix that way. Alternatively, it’s also possible to do strength work in a Tabata style. For example, you could do a three cycle 12-minute workout in which pull-ups, push-ups, and squats are performed at high-intensity. There are many, many other possible combinations.

Another drawback of HIIT is that it can be emotionally tough at times. As noted earlier, if high-intensity is not to your liking, just stick to what works.

Lastly, HIIT may also prove challenging for individuals who are considerably out of shape, obese, or who are dealing with cardiovascular or other health issues. It’s not the kind of thing that can be immediately rushed into, lest there be plenty of wheezing and nausea. For those still keen to do it, my advice would be to take it easy the first few times, and resist the urge to go to full exertion.


Images: Tabata via, wall ball image via crossfitpc, VO2 test via Yahoo!.