Does a 12-week high-intensity interval training (HIIT) program show superior glucose control in type 1 diabetes than other forms of exercise?
Patients with diabetes can improve their glycemic control and insulin resistance by exercising. Regular exercise will help with weight loss and reduce the occurrence of cardiovascular risk factors. Fitness training also helps develop strength, flexibility, and muscle endurance, and significantly enhances overall health. The American Diabetes Association recommends 150 mins or more of moderate to vigorous-intensity activity weekly. New studies reveal that, specifically, high-intensity interval training (HIIT) could improve glucose metabolism in a shorter time than an exercise of moderate intensity. HIIT helps burn many calories in a short time frame and can improve metabolism. A randomized control trial with partial crossover investigated the effects a 12-week randomized HIIT program had on the glycemic control of adult type 1 diabetes patients with overweight or obesity.
The randomized control study analyzed 30 inactive adults aged 44 ± 10 years with a diabetes duration of 19 ± 11 years. They had a BMI of >25kg/m2 and HbA1C levels of >7.5%. The study divided the 30 inactive adults into two groups using computer-generated randomization: 15 patients assigned to HIIT intervention and 15 set as the control group. The HIIT exercise intervention occurred three times a week for a 12-week duration period. In a partial crossover design, the control group subsequently performed the HIIT program. Exclusion criteria included a patient with a medical condition limiting exercise participation, inability to undergo an MRI scan, and pregnant or breastfeeding women. The 12-week HIIT exercise intervention control group participants experienced four reps for four minutes (4 x 4-min) HIIT with an 85% to 95% peak in heart rate. The control group continued their usual daily exercise and diet. The primary endpoints were the change in HbA1C from baseline to the 12-week mark. The outcomes were measured at the 0, 12, and 24-week mark to analyze the glycemic and cardiometabolic results. The study visits and exercise sessions were supervised. Each HIIT exercise session lasted for 33 minutes, consisting of a 5 min warm-up at 60% peak heart rate, then four bouts for 4 min high-intensity intervals at 85-95% heart rate peak, interspersed with three episodes of three recovery intervals at 50-70% heart rate peak. The control group also completed the HIIT exercise intervention unsupervised or at home during the partial cross over 12 weeks. To record adherence data, a heart rate monitor and Bluetooth linked smartphone application was used.
Results showed an increase in HbA1C by 0.53 ± 0.61% for the HIIT intervention group after 12 weeks, while the HbA1C decreased 0.14 ± 0.48% (P = 0.08) for the control group. This indicates that there was not a significant difference between the groups. HbA1C decreased from 8.63 ± 0.66% at baseline to 8.10 ± 1.04% at 12 weeks for the HIIT intervention group, which notably was not as big of a difference when compared to the control group: −0.53 ± 0.61% vs. control −0.14 ± 0.48% (P = 0.08). This study also relied heavily on participant adherence to showcase these positive results. Depending on how adherent participants were in the intervention, the HbA1C improved. Patients who participated at least 50% of the intervention group’s duration had a more significant effect on their glycemic control: HbA1C −0.64 ±.64% for 9 participants in the HIIT group vs. −0.14 ± 0.48% (P = 0.04) for 15 patients for the control. This study considered differences between insulin dosing, glucose monitoring, blood pressure readings, body weight, and body composition between the two groups. Still, no significance was found regarding the impact of these factors on glycemic control results with HIIT.
This trial successfully demonstrated a decrease in glycemic control with greater adherence to high-intensity interval training. However, the results did not show any significant reduction in the HbA1C levels. Further longitudinal studies are needed to evaluate a larger, more diversified population to determine the HIIT effect on decreasing glucose. However, this study has emphasized that physicians should regularly promote glycemic control and encourage HIIT programs.
- High-intensity interval training decreased HbA1C for patients adherent to at least 50% of the intervention compared to the control.
- Glycemic control may improve for type 1 diabetes patients who participate in HIIT (high-intensity interval training).
- While this study mentions the benefits of HIIT lowering BMI, further studies are needed to demonstrate the combined effect of HIIT and weight loss on glycemic control.
Lee, Angela S., et al. Effect of High-Intensity Interval Training on Glycemic Control in Adults With Type 1 Diabetes and Overweight or Obesity: A Randomized Controlled Trial With Partial Crossover, Diabetes Care, September 1, 2020
Sjöros, T. J., et al. Increased Insulin‐Stimulated Glucose Uptake in Both Leg and Arm Muscles after Sprint Interval and Moderate‐Intensity Training in Subjects with Type 2 Diabetes or Prediabetes. April 10. 2017,
Aleksandra Kusic, PharmD Candidate, Florida A&M University, College of Pharmacy and Pharmaceutical Science.