If you have picked up a health and fitness magazine in the last three to five years then chances are you have read an article detailing high intensity interval training. Probably more specifically detailing how well it works for accelerating fat-loss. But for some reason a lot of people are continuing to hang on to their old routines of 30 minute walk on the treadmill at the same 3 mph. Time and time again both research and anecdotal evidence has proven that high intensity exercise tends to be better suited for fat loss versus other lower intensity modalities. And here is another one of those examples! Of course this study was looking specifically at adolescent girls, but still it useful implications for other populations.
by Racil, Ounis, Hammouda, Kallel, Zouhal, Chamari, and Amri
published 2013 in the European Journal of Applied Physiology
Obesity is correlated with development of chronic diseases that include metabolic syndrome, type 2 diabetes, cardiovascular disease, and cancer. Clinicians use a number of markers to monitor the development of such diseases such as blood sugar, blood serum cholesterol, triglycerides, and insulin resistance. But levels of adiponectin, which is a protein released by adipose tissue, are inversely proportional to obesity and insulin resistance.
The effects of exercise and physical activity on adiponectin has not been established. Previous research has supported that high intensity interval training may be beneficial for fighting obesity and may be associated with improvements in cardiovascular health and other parameters then when compared to low or moderate exercise.
Researchers desire was to explore the effects of a 12 week high intensity interval training program on plasma lipids, body composition, and adiponectin levels in obese adolescent girls.
34 obese Tunisian girls were recruited and assigned them to either a high intensity exercise group, a moderate intensity exercise group, or a non exercising control group.
The high intensity exercise program comprised running intervals at 100 to 110 percent of maximum aerobic speed. The moderate intensity interval training program comprised running intervals at 70 to 80 percent of maximum aerobic speed. Both of these groups performed their training programs 3 times per week on non consecutive days over the 12 weeks. All intervals were performed with active recovery and on an outside 200 meter track. Each interval comprised 30 seconds of work with 30 seconds of rest. These sessions were always supervised.
Researchers then measured anthropometric measures, VO2 max, maximal aerobic speed, and peak heart rate before and after the 12 week intervention.
Researchers reported that both training groups reduced body mass and body fat percentage significantly during the 12 week intervention, but the control group showed no change. Researchers note that the high intensity interval training group significantly reduced waist circumferences. Researchers reported that both VO2 max and minimum aerobic speed improved in the training groups, but improved greater in the high intensity interval training group.
Researchers reported that significant improvements occurred in the high intensity interval training group for total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, adiponectin, insulin and homoeostasis model assessment index for insulin resistance. High intensity group produced significant improvements across a wider range of health markers.
Researchers concluded by stating that high intensity interval training produced superior improvements in both measures of body composition, cardiovascular fitness, and health markers than a moderate intensity interval training program in obese girls. Due to this researchers suggest that high intensity interval training may therefore be a better approach for prevention of obesity in adolescents.
HIIT is better for fat-loss than lower intensity modalities. Again this isn't ground breaking, but another study to add in support of HIIT for fat-loss. The evidence just keeps stacking up!
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