Here’s the fastest way to burn calories

Most of us forego exercising because we think it requires a lot of commitment and time. A series of recent studies found that the reality is much easier and a very (very) short workout is enough.

 Walking (photo credit: INGIMAGE)
(photo credit: INGIMAGE)

Many people believe that in order to maintain fitness they need to exercise at least an hour a day, but research shows that only a few seconds are enough. According to a new study examining the power of super-fast workouts that are repeated about 20 times daily, a few seconds at a time may be all we need to build and maintain fitness and strength. Four, to be exact.

Almost anyone who has a passing interest in exercise has probably heard of high-intensity interval training (HIIT), a workout of short, intense and repetitive bursts of exercise called intervals, with rest periods of a few seconds in between.

However, the ideal length of each interval (each burst of exercise), remains unclear. What is certain is that such intense training shouldn’t be too exhausting, and any interval should be as strenuous and tolerable as possible.

For Dr. Edward Coyle, an expert in kinesiology (science of body movement) who heads the Human Performance Lab at the University of Texas at Austin, that means a period of about four seconds. 

He and his colleagues came to this number after examining professional athletes. During physiological tests in Dr. Coyle's lab, the athletes created speed and power while pedaling on special stationary bikes equipped with a heavy wheel which had no resistance. Within two seconds of pedaling these unique bikes,  the researchers saw that the athletes reached an overall level of aerobic effort which they maintained for a short time while continuously repeating the motion, with a few seconds of rest between exercises.

Since we aren’t all professional athletes, Dr. Coyle's estimate for the general public was double the time i.e. four seconds. But can four seconds really provide enough exercise? To try to find out, he and his colleagues conducted a series of additional experiments.

During the first study published last year, they asked college students to complete five repetitions of four-second intervals on the specially designed bike, each hour over an eight-hour workday. They found that the subjects’ metabolized fat much quicker the next day than if they hadn’t exercised at all.

In a broader study in which unfit adults participated, it was found that four-second interval training sessions, during which volunteers repeated short but intense intervals on the bike at least 15 times per session, significantly increased aerobic fitness and leg muscle mass after eight weeks.

Get up and walk around during the day

For the latest and most recent study, published in Medicine & Science in Sports & Exercise, Dr. Coyle and colleagues examined 11 healthy and active young people who did 30 strenuous four-second reps on the bike, with a rest of at least 15 seconds in between. The volunteers came three times a week for eight weeks.

After the experiment, the researchers found that the volunteers added 13% to their aerobic fitness measurement and 17% to their muscle strength, measured in how many watts they produced while cycling. These results suggest that a few seconds of strenuous exertion "definitely provide enough stimulation" to strengthen even already strong muscles, said Dr. Coyle.

"In general, it's a good idea to get up and walk around during the day," said Coyle, who has also researched sedentary lifestyle and its harmful effects, "and then sometimes, too, walk around intensely," even for a few seconds.