Short-Term High-Intensity Interval Training Reduces Hyperglycemia in Type 2 Diabetics

Abstract

Glycemic regulation is impaired in individuals with type 2 diabetes (T2D). Current guidelines recommend that people with T2D should participate in a cumulative total of 150 minutes of continuous, moderate-intensity aerobic exercise each week, or at least 90 minutes of vigorous intensity exercise. While effective for improving glycemic control, most individuals with T2D do not perform sufficient activity to achieve health benefits, often citing "lack of time" as a key barrier to regular exercise participation. Low-volume high-intensity interval training (HIT) is a potent stimulus for inducing metabolic adaptations typically associated with traditional high-volume endurance training. However, the effects of low-volume HIT on glycemic control in people with T2D is currently unknown. PURPOSE: To determine the utility of HIT to reduce hyperglycemia in patients with T2D in a practical, time-efficient manner. METHODS: 7 subjects with T2D (age: 62 ± 3 yr, BMI: 33 ± 3.8 kg/m2, Wmax: 125 ± 18 W) performed 6 training sessions over 2 wk. Each session consisted of 10 × 1 min cycling efforts at ∼90% Wmax elicited during a ramp VO2peak test, interspersed with 1 min of rest (113 ± 11 W). Continuous Glucose Monitoring (CGM) technology (Medtronic CGMS® iPro Recorder) was employed under standard dietary conditions for a 24 hr period on a pre-training control day and ∼48-72 hr following the final training session. RESULTS: CGM data revealed lower mean 24 hr blood glucose concentration following HIT (7.6 ± 0.5 mmol/L vs. 6.6 ± 0.3 mmol/L, p < 0.05). The sum of the 3 hr postprandial area under the glucose curve for breakfast, lunch and dinner was also reduced following training (689 ± 196 mmol/L × 9hr vs. 991 ± 214 mmol/L × 9hr, p < 0.05). CONCLUSIONS: These preliminary data shed light on the potential for low-volume HIT to represent a unique, time-efficient exercise strategy to improve glycemic regulation in people with T2D. Supported by the Canadian Diabetes Association