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science nutrition <strong>blog</strong>

High-intensity interval training (HIIT)— repeated bouts of high-intensity exercise followed by rest— builds fitness quickly. Canadian researchers found that six sessions of high-intensity interval training on a stationary bike increased muscle oxidative capacity (citrate synthase) by almost 50 percent, muscle glycogen by 20 percent and cycling endurance by 100 percent. The subjects made these amazing improvements exercising a mere 15 minutes in two weeks. This study caused a frenzy in the fitness industry, which changed the way many people train. Does HIIT provide the same health benefits as traditional, moderate-intensity training (MIT)? A study led by Gordon Fisher from the Department of Human Studies, University of Alabama at Birmingham, concluded that HIIT and MIT had similar effects on aerobic capacity, body composition, insulin sensitivity, blood pressure and blood fats. Twenty-eight sedentary, overweight men practiced HIIT or MIT for six weeks. The HIIT program consisted of four 30-second sprints on a stationary bike at 85 percent of maximum effort, while MIT consisted of 45 to 60 minutes of cycling at 55 to 65 percent of maximum effort. HIIT produced the same changes in one hour per week as MIT did in five hours per week. (PLoS ONE, 10(10): e0138853, 2015)