An increasing interest in high intensity interval training (HIIT), sometimes simply called high intensity training (HIT), has led more and more people to wonder about the benefits of this exercise approach. Here are some of the latest findings about the impact of high intensity interval training.
What is high intensity interval training?
For the uninitiated, high intensity interval training is an exercise or workout technique in which you alternate between set periods of vigorous or intense activity (e.g., running, spinning, rowing) with fixed periods of less intense exercise. Each individual’s program of HIT will differ depending on his or her age, state of health, physical limitations, and other factors.
HIT offers many benefits, and one that is attractive to many people is time: a 15 or 20 minute workout several times a week is all that’s generally needed to reap the rewards (some of which are discussed below). If you feel you have no time to exercise, HIT might be for you. For example, you might spin as fast as you can for 90 seconds, spin slowly for 60 seconds, and then repeat this cycle five more times for a total of just 15 minutes.
Some benefits of HIT
Muscles. High intensity interval training stimulates fast-twitch muscles. This is important for several reasons. One, traditional cardiovascular exercise, such as 30 minutes of brisk walking or jogging, helps develop slow-twitch muscles but not fast-twitch muscles. Therefore, the fast-twitch muscles can atrophy or decline.
If, however, you engage in HIT several times a week, you give your fast-twitch muscles a workout. Two, working your fast-twitch muscles can improve muscle tone, mass, and strength. These improvements in muscle health are benefits for people of all ages, especially older adults, as it can help them maintain mobility and self-sufficiency.
Hormones. High intensity interval training raises the body’s production of human growth hormone. The level of this hormone declines with age, beginning around age 30. Human growth hormone is often referred to as an antiaging hormone, and some people take HGH to fight the aging process. HIT is a natural way to boost HGH levels.
Weight loss. High intensity interval training boosts metabolism, which in turn burns more calories and can help with weight loss. A recent study from the University of Notre Dame noted that the “numerous benefits” of aerobic exercise, “especially weight loss, are amplified with HIIT.” Since HIT doesn’t require a lot of time, it is a convenient addition to a weight loss program that also includes a healthy, low-fat eating plan.
Overweight and obesity. Although this benefit includes several of the other advantages of HIT, it warrants a separate mention because of the epidemic of overweight/obesity and the significant challenge it presents. Evidence of the benefits comes from a recent study conducted at the Montreal Heart Institute.
In that study, 62 overweight and obese adults participated in a nine-month program that included nutritional counseling, high intensity interval exercise, and resistance training two to three times per week. Ninety-seven percent of the participants completed the program.
Significant improvements were seen in body mass, maximal exercise capacity, cholesterol and triglyceride levels, total fat mass, and waist circumference. The authors concluded that a long-term program that includes HIT is “safe, efficient, and well tolerated and could improve adherence to exercise training in this population.”
High blood pressure. A new review of HIT and high blood pressure (hypertension) reports that HIT has indicated greater benefits than continuous moderate-intensity exercise (CMT) in preventing and controlling high blood pressure. Specifically, HIT has been shown to be superior to CMT in improving insulin sensitivity, stiff arteries, and cardiorespiratory fitness, among other indicators, in people with hypertension.
Performance. For runners who are really interested in improving performance times, a study from the University of Copenhagen suggests a specific routine using HIT. According to professor and former assistant coach Jens Bangsbo at the University, a high-intensity, 30-minute workout performed three times a week for seven weeks forces the body to use muscle fibers not normally utilized and also helps individuals better deal with fatigue.
For example, Bangsbo suggests engaging in 10 to 30 seconds of high-intensity running (at 90 to 95% of maximum) followed by short intervals of medium-intensity and low-intensity activity for a short time (typically 2-3 minutes), depending on the individual’s goal.
This is just an overview of the many benefits of HIT and is meant to pique your interest in its many possibilities. Readers who are interested in learning more about high intensity interval training are encouraged to follow the research and talk to knowledgeable professionals about this exercise technique.
Ciolac EG. High-intensity interval training and hypertension: maximizing the benefits of exercise? American Journal of Cardiovascular Disease 2012; 2(2): 102-10
Gremeaux V et al. Long-term lifestyle intervention with optimized high-intensity interval training improves body composition, cardiometabolic risk, and exercise parameters in patients with abdominal obesity. American Journal of Physical Medicine and Rehabilitation 2012 Nov; 91(11): 941-59
Shiraev T, Barclay G. Evidence based exercise—clinical benefits of high intensity interval training. Australian Family Physician 2012 Dec; 41(12): 960-62