The Real Benefits of High Intensity Interval Training
Sara Thompson, MSc, Faculty of Kinesiology and Physical Education, Human Physiology Research Unit, University of Toronto
As people age, there are changes to processes that happen at a cellular level. Examples include a decrease in the activity of enzymes, higher blood sugar levels, and a less efficient way of handling sugar. In addition to affecting physical function and fitness, these physiological changes increase the risk of developing chronic diseases, such as cardiovascular disease and type 2 diabetes (Pederson and Saltin, 2006). Endurance exercise improves overall fitness and decreases the risk of chronic disease development. However, in today’s society, most individuals cite that “lack of time” prevents them from attaining their recommended weekly exercise (Korkiakangas et al.,2009).
High intensity interval training (HIIT) is a relatively new exercise trend that offers a solution to this problem. HIIT is a workout comprised of very short high intensity bursts, such as 30-second “all out” sprints on a stationary bike, separated by several minutes of low-intensity pedaling. Interestingly, HIIT has been shown to have the same physiological benefits as endurance training, but with a markedly reduced time commitment. In fact, several studies have demonstrated improvements in fitness and health after only six sessions of HIIT (Burgomaster et al.,2005)!
The Benefits of High Intensity Interval Training for Older Adults
While HIIT has proven to have significant health benefits, the majority of research studies have looked at young adults. However, a recent study by Adamson and colleagues (2014) examined the effects of HIIT on fitness, physical function, and health in a middle-aged population. In this study, 14 untrained middle-aged men and women (average age=43 years old) were divided into either an exercising (HIIT) group or a non-exercising control group. The control group maintained their usual activities throughout the study. The HIIT group completed 16 exercise sessions over 8 weeks, in which the participants performed ten 6-second bouts of “all-out” cycling, separated by 1 minute of rest. Fitness, blood sugar (glucose) regulation and physical function were measured before and after the 8-week intervention.
The results of this study are staggering, especially considering that each session was just 11 minutes long, and only consisted of 1 minute of intense cycling! Following the 8-week program, the control group either remained the same or decreased in all measures, whereas the individuals in the HIIT group improved in all physiological and functional performance tests. Fitness improved by 8% and their ability to regulate blood sugars improved by 6%. Both of these factors are important in cardiovascular disease and type 2 diabetes prevention! Additionally, functional measures (i.e., tests that mimic activities of daily living, such as the ability to get out of a chair and sit back down) improved following 8 weeks of HIIT.
This study sheds light on the fact that very high intensity sprinting type exercise can improve fitness, health and physical function in middle-aged adults. While older adults were not tested in this particular study, these results are very promising. This type of training reduces the physiological problems that begin in middle age and continue into old age, and thereby reduces the risk of disease and functional decline. Most notably, this study shows that it doesn’t take much to reap these health benefits, thereby catering to today’s busy world of work, social and family commitments. It’s not about quantity – it’s about quality!
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Pederson, B.; Saltin, B. Evidence for prescribing exercise as therapy in chronic disease. Scand. J. Med. Sci. Sports 2006, 16, 3–63.
Korkiakangas, E.; Alahuhta, M.; Laitinen, J. Barriers to regular exercise among adults at high risk or diagnosed with type 2 diabetes: A systematic review. Health Promot. Int. 2009, 24, 416–427.
Burgomaster, K.A.; Hughes, S.C.; Heigenhauser, G.J.; Bradwell, S.N.; Gibala, M.J. Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans. J. Appl. Physiol. 2005, 98, 1985–1990.
Adamson, S.; Lorimer, R; Cobley, J.N.; Lloyd, R.; Babraj, J. High Intensity Training Improves Health and Physical Function in Middle Aged Adults. Biology. 2014, 3, 333-344.