We’ve all heard that exercise is important to overall health, yet more than half of Americans don’t get the amount of exercise recommended by the CDC. Studies show that the number one excuse people give for not exercising is a lack of time. Conventional wisdom tells us that to get results from exercise, it’s necessary to invest lots of time to running, walking, cycling, hitting the gym and other activities, but research shows that’s not always the case. Interval training makes it possible to burn fat and strengthen the cardiovascular system with minimal time investments and has been proven effective in numerous studies.
The Basics of Interval Training
During the 1930s, a German running coach named Woldemer Gerschler introduced a revolutionary new training method to his sport, giving birth to modern-day interval training. Gerschler’s idea was that athletes could build endurance more effectively by working alternating between short bouts of strenuous exercise and longer periods of less intense exercise. This key concept is the core of interval training–pushing the body as hard as you can in a short burst and then resting or turning down the intensity until you pick up the pace again.
Aerobic Versus Anaerobic Exercise
To understand why interval training works, you first need to grasp the differences between aerobic and anaerobic exercise. Simply put:
- Aerobic exercise or cardiovascular exercise is powered by oxygen. When the body is in an aerobic state, it is using oxygen from air to convert carbohydrates into energy to meet the demands you’re placing on it. In an aerobic zone, your heart functions at roughly 50 to 80 percent of its maximum rate. During aerobic exercise, you may feel out of breath, but you should be able to maintain a steady pace.
- Anaerobic exercise is not fueled by oxygen. The body instead uses glycogen stored in the muscle tissue as its power source. Anaerobic exercise is incredibly strenuous and can leave you feeling breathless and unable to continue after more than 1 or 2 minutes. When performed for long periods of time, anaerobic exercise leads to a build-up of lactic acid in the muscles that causes soreness and fatigue. Examples of anaerobic exercise include working out with heavy weights, sprinting or jogging if you ordinarily walk.
The Effects and Benefits of Interval Training
During an interval training session, you move your body from a short anaerobic state to a longer aerobic state repeatedly. During the anaerobic period, lactic acid accumulates in the muscles but is then burned during the aerobic period. There are many benefits to alternating between the two forms of exercise, including:
- Increased fat burning. Interval training has been shown to burn more calories and to increase the ratio of fat to muscle that is burned per calorie. In one study conducted at the University of New South Wales in 2008, 20-year-old women of normal weight who had never exercised before completed a 15-week interval training program. They lost more body fat than a similar group of women who did traditional cardiovascular exercise.
- Improvements in cardiovascular function. Over time, interval training greatly strengthens the heart and improves endurance. This has been evidenced by many studies, including a 2006 study published in The Journal of Physiology that found that cyclists who followed a high intensity interval training for 8 weeks could bike for twice as long as they could at the beginning of the study at an identical testing pace.
- Boosts in metabolism function. Interval training greatly improves metabolism function to help you burn fat and fight oxidative damage. A 2002 study found that interval training can increase the production of a key metabolism hormone, human growth hormone or hGH, by 450 percent.
- Reduced soreness. Several studies have confirmed that interval training reduces the risk of feeling sore the day after a workout.
- Less workout burnout. Alternating between high and low intensity intervals keeps workouts challenging and fresh. As a result, you’re less likely to become bored of your fitness routine and give it up or skip sessions.
- More efficient workouts. Perhaps the most exciting benefit of interval training is that it allows you to make big improvements in your fitness level while investing a minimal amount of time. A 2011 study shared at the American College of Sports Medicine Annual Meeting revealed that just 2 weeks of interval training could produce the same gains in cardiovascular and respiratory functioning as 6 to 8 weeks of traditional long distance workouts. Fifteen minutes of alternating between high and low intervals on a treadmill has been shown to equal the calorie burn and other benefits of jogging on a treadmill at a moderate pace in an aerobic zone for an hour.
Getting started with interval training is as easy as mixing short sprints into your run or jogging for short bursts when you head out for a walk. At the gym, try going harder and slower with heavier weights and then rest in between. You can also find DVDs, online workouts and apps that feature interval training workouts. Just be sure to check with your doctor before you begin any new exercise program to ensure best results.