If you've ever said you just don't have time to work out, it's time to find a new excuse.

New research from McMaster University says that all you need for a 'significant' health benefit from your exercise is just one minute of your time.

But, it's a really intense minute.

Martin Gibala, a professor of kinesiology at McMaster University, says that's all it takes. And, he says he has the research to prove it. Below, is an edited and abridged interview with professor Gibala. You can listen to the full interview by clicking the image at the top of this page. 

Martin Gibala, professor of kinesiology at McMaster University

Q. What made you want to study the effects of very brief moments of exercise?

We've been interested in interval training for quite some time now. Over the years we've been increasingly interested in the health effects of small doses of exercises over a short time period.

'We like to think of it as fitting exercise around your life instead of fitting your life around exercise.' - Martin Gibala, professor of kinesiology at McMaster University

Q: What's the best way to spend one intense minute of exercise?

There's a trade off between intensity and duration. Let me say that these types of all out sprint workouts are not necessarily for everyone. But if people are willing and able to exercise at a very intense pace at a very high relative effort you can generate benefits despite a very small dose of exercise. 

In our recent study it was only a minute of very hard work that people were doing. The catch is that the minute was divided into three 20-second bursts of activity with a little bit of recovery. But, even if you include the warm-up and cool down the total time commitment was only 10 minutes, three times per week.

Any way you slice it, it's a small dose of exercise and time commitment, especially when compared to the current public health guidelines. 

Q: Why focus on the value of small workout bursts?

We know the number one cited barrier is lack of time. It's an excuse for some people but, obviously, many individuals lead very busy, time-pressed, lives and they might find it difficult to fit in the time recommended in the public health guidelines.  

For a lot of people, if they don't have a block of 30 or 45 minutes, they'll blow off their workout. Even if you have ten minutes over your lunch hour, perhaps you can go out and vigorously climb a few flights of stairs and know that you will get some significant health benefits from the exercise.  

We like to think of it as fitting exercise around your life instead of fitting your life around exercise.

Q: What should happen in those brief 20-second bursts?

Work out hard. It needs to be very intense. In our studies we told people to go all out for 20 seconds. What's interesting is that when we asked people to rate their perceived exertion on a 20 point scale where 20 is maximum exertion they say it's about 15. So, it is perceived as hard but not perceived as maximum all out exercise.

Q: Does it matter what type of exercise you are doing?

I don't think so. We've also been looking at stair climbing in our laboratory. For anyone who can vigorously climb a few flights of stairs, even if you are just walking up the stairs, it's a practical way that you can apply this. But, running, swimming or rowing, all of the cardio exercises that we think of, could be adopted in an interval manner. 

Cardio and insulin sensitivity benefits

Q: What are the health benefits?

We compared that type of exercise, three 20-second bursts three times per week over twelve weeks, with people who were doing 150 minutes per week of continuous exercise, basically modelling the public health guidelines. We looked at their cardiovascular fitness. We measured that objectively in the lab. Both groups improved their fitness by almost 20 percent over the 12 weeks. 19 percent in both groups.

We also looked at how well people controlled their blood sugar, their insulin sensitivity. We infused an amount of blood sugar into their system and looked at how the body responds to that increase in blood sugar. The improvement in insulin sensitivity was the same in the two groups. We included a control group of subjects who did nothing. They did not improve at all. 

The main takeaway is that both groups improved by the same amount despite very different time commitments in total exercise. 

Q: So, if that 45-minute workout that you planned shrinks down to 10 minutes, it's still worth it?

Absolutely. It's good to boost your health. And, we also know that for athletes who are already very fit, they train this way to maintain fitness. It's a good way to boost your health very, very quickly. Also, as people get more fit other types of physical activity hurt less. It might encourage people to take the stairs more often. I'm not a behavioural psychologist but a lot of my colleagues at McMaster and around the world are looking at this issue of behaviour and how these types of exercises compare when it comes to mood and motivation. 

The traditional thinking is that if exercise is uncomfortable, people won't do it. People seem to be willing to trade off the temporary discomfort of the intervals for the reduced volume of exercise required. There's a lot of interesting behavioural research coming out now. Some suggests that people actually prefer this type of training.

The findings are published online in the journal PLOS ONE. Read the full study here.