With type II diabetes now at epidemic proportions in the western world, there is great interest in any diet, food or exercise that can improve blood glucose control. Researchers from Santiago, Chile have recently added to wealth of data supporting the myriad of benefits of high intensity exercise1. In this particular study, the researchers were particularly concerned with the effect of a basic high intensity exercise regime on blood sugar control in individuals showing signs of type II diabetes. The central measure used to determine the degree of blood sugar control was the blood levels of glucose 2 hours after a 75g dose of glucose. In individuals with good blood glucose control, blood levels of glucose have normally returned to baseline levels (i.e. ~5mmol/L) 2 hours after ingesting 75g of carbs. But when blood sugar control starts to go haywire, it takes longer for glucose levels to get back to normal levels. This is thought to occur as a result of insulin function decreasing.
Subjects in the Chilean study were required to follow a high intensity exercise protocol that consisted of 1 minute of cycling at maximal intensity until muscle fatigue followed by 2 mins rest and repeated 10 times. Subjects had to do this 3 times a week over 3 months and as a result, a significant portion couldn’t keep up with the schedule and had to drop out. This left of total of 10 subjects to pool data. To meet the inclusion criteria, subjects also had to be overweight (with a BMI of greater than 25 but less than 43) and sedentary. They also needed to have blood glucose levels over 7.8mmol/L 2 hours after ingesting 75g of glucose. With these combination of characteristics, the subjects were almost certainly on their way to full blown diabetes!
The relatively simple and time-effective high intensity exercise protocol used in this study lead to a significant improvement in the subjects blood glucose control – possibly the most important risk factor for type II diabetes. With a total exercise time of 90 minutes per week, subjects saw their blood glucose levels drop an average of 1.9 mmol/L two hours after a 75g oral glucose load. These results mirror several others, where a high intensity exercise regime was proven to be effective for blood glucose control in at risk individuals2-5.
The great thing about high intensity exercise is that it provides a myriad of other benefits. In the case of this study, subjects improved their V02max and lost body fat. Other studies have showed it also produces meaningful improvements in endurance despite the exercise itself being highly anaerobic in nature. For a more thorough discussion of the benefits of high intensity exercise, please see our article on High Intensity Interval Training.
1. Little J, et al. Low-volume high-intensity interval training you reduce hyperglycemia and Increases muscle mitochondrial capacity in patients with Type 2 diabetes. Journal of Applied Physiology. 2011;111(6): 1554-1560.
2. Ciolac E. High intensity interval training and hypertension: Maximizing the benefits of exercise? Am J Cardiovasc Dis. 2012;2(2):102-10.
3. Alvarez C, et al. Effects of high intensity exercise and metabolic parameters overloaded health, pre-diabetic sedentary overweight or obese. Rev Med Chile. 2012;140(10):1289-1296.
4. Trapp E, et al. The effects of high intensity intermittent exercise training on fat loss and fasting insulin levels of young women. Int J Obes. 2008;32(4):684-91.
5. Gibala M, et al. Physiological adaptations to low volume high-intensity interval training in health and disease. J Physiol. 2012;590(Pt 5): 1077-1084.