The Times they are Changing
Short spurts of high-intensity training might be just as effective as hours of traditional exercise, according to Canadian researchers.
When it comes to walking across Niagara Falls on a tightrope or selecting a life partner, it probably pays to take your time. In fitness matters, however, speed doesn’t always kill—in fact, current research suggests that faster may even be better or at least equal to slow and steady, especially when the goal is to build endurance.
A recent study conducted at McMaster University in Hamilton, Ontario, and published in the Journal of Physiology, concluded that about 20 minutes of interval training—a short burst of intense exercise such as sprinting, followed by a longer bout of gentler exercise—may offer the same benefits (such as fat loss and improved health and fitness levels) conferred by two hours of traditional exercise performed daily.
“Our study definitely showed that high-intensity interval training improved endurance. We measured specific enzymes that are indicative of the muscle’s ability to use oxygen; the enzymes increased after training by a similar extent in both the high intensity training and endurance training groups. Both groups also showed similar improvements in exercise performance, despite the large difference in training volume between groups,” reports Dr. Martin Gibala, associate professor of kinesiology at McMaster.
Additional research from Laval University in Quebec indicates that interval training can produce a greater decrease in fat levels than a traditional exercise program conducted over the same period of time, according to Toronto-based Maximum Fitness Training advisor Craig Ballantyne, president of CB Athletic Consulting.
“Interval training allows us to bury myths such as the ‘fat burning zone’ and that it takes ‘30 minutes of exercise before your body begins to burn fat.’ While a lot of skeptics dismiss the potential fat-loss benefits because the workouts are so short, [as Dr. Gibala points out] the calories burned in 20 minutes of intervals are the same as in 20 minutes of steady-state-exercise at 70 per cent of VO2max,” says Ballantyne, a regular contributor to Men’s Fitness Magazine who has his Masters Science degree and developed Turbulence Training workouts.
Despite the persuasive results of studies, researchers don’t fully understand the underlying mechanisms that produce such compelling evidence on behalf of high-intensity training techniques.
“…Certainly, interval training appears to ‘recruit’ or stress muscle fibers that are not normally recruited during submaximal endurance training; these fibers adapt or remodel and improve their fatigue resistance,” explains Dr. Gibala.
Interval training is ideal for people pressed for time and is accessible for beginners, yet is still satisfying and productive for athletes possessing a high degree of fitness.
“High-intensity training is not only for elite athletes. However, people should be used at least used to exercise and have some sort of ‘aerobic’ base prior to starting intervals. In addition, obviously anyone should check with their physician before trying an unaccustomed exercise program. The beauty of interval training is the infinite variety (in terms of intensity, duration and number of intervals, plus the recovery intervals) and it can be scaled to any level of fitness. For a person who is only used to walking around the block, interval training might consist of walking at a faster pace than usual, then backing off, and repeating this cycle a few times. A practical method for people is one-minute ‘on’ (or hard), one minute ‘off’ (or easy), repeated 10 times for a 20-minute workout,” says Dr. Gibala.
Make it Quick:
Craig Ballantyne recommends the following interval training regimens:
For the Novice:
Warm up: Five minutes of walking at 3.5 mph.
Speed up and walk at 4.0 for 60 seconds.
Slow down and stroll at 3.0 for 75 seconds.
Repeat steps two and three five more times.
Finish with five minutes of walking at a comfortable pace to cool down.
For the Athlete:
Warm up: Five minutes of jogging or cycling at 30 per cent of your all-out effort.
Run or cycle for 60 seconds at about 80-90 per cent of your all-out effort—the speed you’d run or cycle to save your life equals 100 per cent—from that point, adjust how fast and hard your work so your output reflects the recommended percentage. It should cause your leg muscles to fatigue in about one minute.
Slow down to 30 per cent of your all-out effort for 75 seconds. Make sure you slow down to this very light pace.
Repeat steps two and three five more times.
Finish with five minutes at 30 per cent of your all-out effort to cool down.
“With more experience you can increase the intensity of the interval,” advises Ballantyne who suggests using different modes of exercise to do intervals.
“If you like to train outdoors, you can do hill sprints or run in waist-deep water. In the gym, use the treadmill, cross trainer, stationary bike and even the rowing machine—anything that allows you to increase the workload for a short time and then back off.”