It seems everyone’s ultimate fitness dream would be to achieve the same benefits of time-consuming endurance exercise in a fraction of the time.
Well, it’s not just a dream. With high-intensity interval training (HIIT), this dream can be a reality.
HIIT is not for the faint of heart. It can be difficult, but fortunately, it can be incorporated into many different exercise regimens. And, the benefits are too great to ignore.
What Does HIIT Mean?
HIIT is essentially interval training, but with a twist. Short for high intensity interval training, HIIT is a method of cardiovascular exercise that alternates short periods of intense exercise with periods of less-intense exercise.
When your exercise stays consistent, your body stays consistent. When you push yourself to work harder, your body adapts and changes. This concept explains why HIIT works so well.
Benefits of HIIT
Science shows HIIT is equal to—if not superior to—long periods of endurance exercise. Just what is HIIT doing for you? Here’s a closer look:
Performance and Power
Scientists have found “brief, intense exercise training may induce metabolic and performance adaptations comparable to traditional endurance training.”
In a cycling study, subjects performed 4 to 6 repeats of 30 second all-out cycling with 4 min recovery, or 90 to 120 minutes of continuous cycling. The results were similar: both increased muscle oxidative capacity, muscle buffering capacity, and muscle glycogen content.
Yet another study found sprint interval training and endurance training increased muscle oxidative capacity. Clearly, HIIT produces similar results in terms of athletic performance as endurance training.
You may be tempted to believe the only way to improve cardiovascular endurance is to exercise for long time periods. However, HIIT also holds the key to enhancing endurance.
In a study, HIIT increased maximal oxygen uptake, an important way of measuring physical fitness and endurance capacity, more than did slow long distance exercise.
Stroke volume of the heart, or the volume of blood pumped with each beat, also increased by 10% after HIIT. This indicates improved cardiac function, resulting in a lower resting heart rate, which is a sign of improved physical fitness.
One study showed HIIT, but not low intensity steady training, improves body composition. It also optimizes resting metabolic rate for 24 hours post-exercise, indicating a maximized ability to rapidly burn calories.
Another study comparing the two forms of exercise found the HIIT group significantly reduced total body mass, fat mass, and stomach fat. HIIT also optimized insulin resistance, leading to a decreased tendency to store fat.
How to Do HIIT
Fortunately, HIIT is easily incorporated in most aerobic sports; these include running, biking, hiking, rowing, skiing, and aerobics.
There’s no perfect formula for a HIIT workout, but the following is an example of what a beginning HIIT workout might look like:
- Minutes 1-4: Jog at 50% effort
- Minute 5: Sprint 30 seconds at maximum effort; Jog/walk 30 seconds
- Repeat for minutes 6, 7, and 8
- Minutes 9-12: Jog at 50% effort
As you improve, you can amp the number of intervals you perform, as well as the intensity.
Are you convinced HIIT is the way to go? Remember, anaerobic exercise and endurance exercise have their benefits as well, so there’s no need to give them up.
But, incorporating HIIT into your exercise program leads to better athletic performance and health. When you hit the ground with HIIT, you may perform at a level you never dreamed possible.
-  Martin J. Gibala et al. “Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance.” The Journal of Physiology. 2006; 575: 901-911.
-  Jonathan P. Little et al. “A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms.” The Journal of Physiology. 2010; 588: 1011-1022.
-  Helgerud J. et al. “Aerobic high-intensity intervals improve VO2max more than moderate training.” Med Sci Sport Exerc. 2007; 39 (4): 665-71.
-  Jeffrey W. King. “A Comparison of the Effects of Interval Training vs. Continuous Training on Weight Loss and Body Composition in Obese Pre-Menopausal Women.”
-  E.G. Trapp et al. “The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women.” International Journal of Obesity. 2008; 32: 684-691.
-  “What is the Best HIIT Workout?”