High-Intensity Training: Not Only for Building Muscles!

Short Communication

Exercise has been shown to reduce glucose concentrations in blood [1]. In fact, one week of aerobic exercise has been shown to reverse type II Diabetes [1]. Traditionally, it has been assumed that the best way to reduce blood glucose concentrations in insulin resistance is with moderate intensity long duration exercise. More recently, the utility of high-intensity short duration exercise has been realized [2]. For example, Ryan, et al. [2] reported that 10, one-minute bouts of exercise at 90% of heart rate maximum for 12weeks resulted in significant and similar improvement in insulin sensitivity as 45min of exercise at 70% of heart rate maximum. Four sessions per week were performed in each group. Likewise, Naufahu, et al. [3] reported that one, one hour session (6x30s Wingates with 9.5min rest in between each 30s bout) was superior at improving insulin sensitivity and area under the glucose curve in pre-diabetic individuals than exercise at 90% of the lactate threshold. In an excellent review article, Consitt, et al. [4] has detailed the beneficial effects of resistance exercise which involves short duration high-intensity bouts of exercise interspersed with rest periods on insulin action. These benefits are at least as effective as the effects of long duration moderate intensity exercise [4]. The operative mechanism for the short-term effects of high-intensity training are likely increases in Glut-4 protein as work from Tabata’s group showed that 280s of intermittent high-intensity swimming in rats led to similar increases in Glut-4 protein as 6h of training at low intensity [5]. Each group exercised 8 days in a row. Very practical data, from John Kirwan’s group [6,7] suggest that 15-20minute Cross-Fit high-intensity workouts for 6weeks are sufficient to improve insulin sensitivity.

References

• Kirwan JP, Solomon TP, Wojta DM, Staten MA, Holloszy JO, et al. (2009) Effects of 7 days of exercise training on insulin sensitivity and responsiveness in type 2 diabetes mellitus. Am J Physiol Endocrinol Metab 297(1): E151-156.
• Ryan BJ, Schleh MW, Ahn C, Ludzki AC, Gillen JB, et al. (2020) Moderate-Intensity Exercise and High-Intensity Interval Training Affect Insulin Sensitivity Similarly in Obese Adults. J Clin Endocrinol Metab 105(8): e2941-2959.
• Naufahu J, Elliott B, Markiv A, Dunning Foreman P, McGrady M, et al. (2018) High-Intensity Exercise Decreases IP6K1 Muscle Content and Improves Insulin Sensitivity (SI2*) in Glucose-Intolerant Individuals. J Clin Endocrinol Metab 103(4): 1479-1490.
• Consitt LA, Dudley C, Saxena G (2019) Impact of Endurance and Resistance Training on Skeletal Muscle Glucose Metabolism in Older Adults. Nutrients 11(11): 2636.
• Terada S, Yokozeki T, Kawanaka K, Ogawa K, Higuchi M, et al. (2001) Effects of high-intensity swimming training on GLUT-4 and glucose transport activity in rat skeletal muscle. J Appl Physiol (1985) 90(6): 2019-2024.
• Nieuwoudt S, Fealy CE, Foucher JA, Scelsi AR, Malin SK, et al. (2017) Functional high-intensity training improves pancreatic beta-cell function in adults with type 2 diabetes. Am J Physiol Endocrinol Metab 313(3): E314-E320.
• Fealy CE, Nieuwoudt S, Foucher JA, Scelsi AR, Malin SK, et al. (2018) Functional high-intensity exercise training ameliorates insulin resistance and cardiometabolic risk factors in type 2 diabetes. Exp Physiol 103(7): 985-994.