Have No Fear, High Intesity Exercise Isn’t That Intense

Contributed by Julianne Barry, PhD Student, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus

Two of the reasons that people don’t exercise are “lack of enjoyment” and “lack of time”. Although “lack of time” is the number one stated reason why people don’t exercise, let’s face it, when you enjoy doing something you are more likely to continue doing that activity. 

Let’s dive into some exercise lingo. CMI, CVI, HIIT. Where do we start! CMI is short for continuous moderate intensity exercise and an example is brisk walking. Moving up the intensity scale we enter into CVI or continuous vigorous intensity exercise, such as hiking or jogging. At this end of the scale we also find HIIT or high intensity interval training. HIIT comprises of short bursts of vigorous exercise separated by recovery or rest periods and has been shown to be more time-efficient than continuous exercise.

Time to explore our exercise options. First we have the more classically prescribed 40 minutes of brisk walking (CMI). Secondly, we can choose to increase our intensity and go for a 20 min vigorous jog (CVI) or we can choose 10 short bursts of vigorous exercise (HIIT) with periods of recovery for a total of 20 minutes instead. Which type of exercise would you choose and more importantly which one would you stick with? Remember, lack of time and lack of enjoyment are two top barriers against exercise.

Research has shown that enjoyment of exercise decreases as exercise intensity increases. For example, participants enjoy moderate cycling (CMI) more than vigorous cycling (CVI).

If this is the case, what can we say about enjoyment of HIIT? Research may show mixed results because there are different types of HIIT. The traditional HIIT style of Wingate cycling, which comprises of four to six “all out” 30 second sprint bursts, is an exhausting process. A more practical version of HIIT is a “low volume” program that consists of 10 x 1 minute intervals that are at a lower intensity than Wingate cycling (Gibala, Little et al. 2012). This program has been proven effective for healthy individuals as well as overweight and type 2 diabetic individuals. One study demonstrated that type 2 diabetic participants found “low volume” HIIT highly enjoyable (Little, Gillen et al. 2011).

Several studies have looked closer into the enjoyment of HIIT. Three studies have compared the enjoyment of HIIT to continuous exercise such as CVI and CMI. The first study demonstrated that high intensity interval running (HIIT) was perceived as more enjoyable than moderate-intensity continuous CMI, even though HIIT was also perceived to be a harder exercise program (Bartlett, Close et al. 2011). Another study that compared HIIT and CMI showed that participants were more likely to stick with high intensity functional training (HIIT) than moderate intensity aerobic and resistance training (CMI) (Heinrich, Patel et al. 2014). The last study compared cycling exercise as CMI, CVI and HIIT. Although HIIT was found to be as enjoyable as CMI, it was still more enjoyable than CVI. In addition, participants were more confident that they could perform HIIT or CMI three or five times a week. Although HIIT was as enjoyable as CMI, participants preferred HIIT over CMI (Jung, Bourne et al. 2014).

The take home message of today is that HIIT removes exercise barriers because it is both quick and enjoyable. HIIT has been found to be highly enjoyable and in some studies more enjoyable than other continuous exercise styles. This doesn’t mean that HIIT may be the right program for you. Any exercise program that you enjoy and that you can stick with is the exercise for you. Yet in the future, don’t be afraid of trying HIIT. It’s fun!

Sources:

Bartlett, J. D., G. L. Close, D. P. M. MacLaren, W. Gregson, B. Drust and J. P. Morton (2011). “High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: Implications for exercise adherence.” Journal of Sports Sciences 29(6): 547-553.

Gibala, M. J., J. P. Little, M. J. MacDonald and J. A. Hawley (2012). “Physiological adaptations to low-volume, high-intensity interval training in health and disease.” The Journal of Physiology 590(Pt 5): 1077-1084.

Heinrich, K. M., P. M. Patel, J. L. O’Neal and B. S. Heinrich (2014). “High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study.” BMC Public Health 14: 789.

Jung, M. E., J. E. Bourne and J. P. Little (2014). “Where Does HIT Fit? An Examination of the Affective Response to High-Intensity Intervals in Comparison to Continuous Moderate- and Continuous Vigorous-Intensity Exercise in the Exercise Intensity-Affect Continuum.” PLoS ONE 9(12): e114541.

Little, J. P., J. B. Gillen, M. E. Percival, A. Safdar, M. A. Tarnopolsky, Z. Punthakee, M. E. Jung and M. J. Gibala (2011). “Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes.” Journal of Applied Physiology 111(6): 1554-1560.