“I’m too busy.” Do you hear that from friends who don’t do things that are good for them, like exercise? What they mean is: “I’m busy doing things that I’d rather do than exercise.”
McMaster University in Ontario, Canada, for reasons unknown to me, has been a major source of research in the field of high-intensity interval training (HIT). The initial research focused on HIT that involved all-out effort – working in bursts of 30 seconds, followed by four minutes of recovery on a special bicycle. This level of effort can be painful. As participants ran out of stored glycogen and become anaerobic, their quads burned and they gasped for air. Maintaining this regimen for four to six intervals takes dedication.
Two years ago, Martin Gibala, chair of the Department of Kinesiology at McMaster, expanded the research to include eight to twelve one-minute bursts on a standard stationary bicycle at a lower intensity with rest intervals of 75 seconds for a total time of 20 to 25 minutes per session. While this involves working at up to 95 percent of maximum heart rate (MHR), it’s considerably below the all-out effort previously studied.
The good news is that the benefits obtained in both methods are equal to or greater than those from long-duration endurance training – aerobic exercise at 60-70 per cent of MHR for one hour or more. But, there is no free lunch; lower-intensity HIT involves more time than the all-out effort, although still much less than standard endurance training.
This type of exercise helps retain fast-twitch muscle fibers, the ones that tend to go away as we age because we don’t use them enough. Fast-twitch muscle fibers allow us to hit the golf or tennis ball with more power, for example. It also helps improve our brain function by generating neurogenesis – the growth of new brain cells – and reduces the risk of diseases, such as type 2 diabetes.
Dave, one of my cycling buddies, had a nasty fall last October where he cracked his pelvis. He was in a wheelchair and then on crutches for several weeks, which was followed by physical therapy. He started biking again three months later; the surprise to all of us is that he returned stronger than before the fall.
During a break on our ride, a cyclist asked him how he did it. He said, “When I was recuperating, I remembered Harry talking about high-intensity interval training and decided to give it a try. I found it works. I got more done in less time and got stronger.” I should mention that Dave is in his mid-60s.
No matter how you exercise (walking, biking, swimming or a spin class), try incorporating low-intensity intervals, or even all-out effort intervals, into your work out.