Kinected: High-intensity offers surprising benefits

High intensity sprint drills, or interval training, have been used for many years by athletes to improve speed, quickness and power

High intensity sprint drills, or interval training, have been used for many years by athletes to improve speed, quickness and power in sports.

But since the mid-1990s, there have been investigations by researchers on the effect this kind of training has on non-athletes. This research has been showing increasingly beneficial results on everything from weight control to blood sugar regulation. This high intensity interval training is sometimes called HIIT for short.

Interval training is usually defined as exercising at high intensity or speed for a short period of time (often 10 to 30 seconds) using a large amount of muscle mass doing an activity such as running or cycling, followed by a rest period, then repeating the process a number of times in one training session.

Rest periods consist of either complete rest, or up to about 50 per cent of maximum working intensity.

Decades ago it was assumed by the public and athletes alike that if you wanted to improve your aerobic performance, you should do only aerobic exercise (like long runs) and to improve anaerobic performance you need to do anaerobic exercise (like sprinting). We thought doing anaerobic exercise would not improve the aerobic benefits on the body like fat loss, improved aerobic capacity, blood sugar regulation or heart health.

However, many recent studies are changing this view. In 2008 a paper was published by researchers at McMaster University that showed that doing 2.5 hours of sprint interval training produced similar biochemical muscle changes to 10.5 hours of endurance training and similar endurance performance benefits.

The interval used was one minute of high intensity work followed by 75 seconds of rest repeated 8-12 times, three days a week compared to five days a week of the traditional aerobic workout.

The McMaster study also found a benefit to a less intense interval program for those who were very sedentary.

Another researcher at the University of Birmingham found using a similar interval training regimen with as little as three 20-second intervals each week for four weeks improved insulin sensitivity by 24 per cent.

In another study by the same researchers, a 15-week program of HIIT on a group of young women showed significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance.

The reason for these effects is not completely understood, but may have to do with the fact that when you exercise at very high intensities, you use more of the working muscle mass, and this may stimulate these systemic changes in your body, improving both the aerobic and anaerobic systems.

The implication for those who do not like exercise or feel they never have an hour a day to do a workout is that these drills can take as little as 10 or 15 minutes to do and have many benefits to fitness, metabolism and body composition.

Always seek the advice of your family doctor before embarking on an exercise program.


Kerry Senchyna holds a bachelor of science degree in kinesiology.