With our increasingly busy modern lives, it's often difficult to fit everything we'd like in to all of our days. Getting exercise is of course very important, especially if you drive to work and spend most of your days sitting at a desk. But, luckily, consensus from the experts is that short workouts really do work.
Though it's recommended that adults get 30 minutes of cardio exercise a day, this is very difficult when it's necessary to balance work, raising children and taking care of one's home - not to mention getting enough sleep each night so you can start the day refreshed. But it turns out that mixing interval training into one's schedule can help. For example, though a 30-minute, moderately paced walk burns 112 calories, mixing just eight 30-second speed-walking sprints into the 30-minute walk – for a total of four extra minutes – will enable you to burn 165 calories.
In a recent Oprah.com article, Dr. Martin Gibala said that doing short, intense workouts actually helps us get fitter in less time:
"Your body thinks, 'Whoa! That was hard work,' and it responds by increasing your ability to use oxygen and burn fat," Gibala said.
This is because intense, short workouts work fast-twitch muscle fibers – those responsible for speed and power. In contrast, during a brisk walk, we typically use mostly slow-twitch muscle fibers, which are built for endurance.
In a study Gibala led at McMaster University, half of the participants engaged in 20- to 30-minute cycling workouts with six 30-second "sprints," while the others engaged in a 90 to 120 stationary bike workout at lower-intensities. After two weeks, the people who worked out in intense intervals were just as fit as those who worked out up to four times longer.