Moderate-intensity continuous training: is it as good as high-intensity interval training for glycemic control in type 2 diabetes?

In Egypt, type 2 diabetes is higher in females than in males. Moderate-intensity continuous training (MICT) has been the most widely used exercise form in type 2 diabetes. This study aims to compare the classical MICT to the newly popular high intensity interval training (HIIT) with regard to changes in glycosylated hemoglobin (HbA1c) and estimated average glucose (eAG) in female type 2 diabetics. Twenty-six female patients with type 2 diabetes were assigned into three groups: a control group (n=9), a MICT group (n=9), and a HIIT group (n=8). Patients in both groups exercised on treadmill three days/week for 8 weeks. Patients in MICT exercised continuously for about 40 min at 65%-75% of peak heart rate (HRpeak). Patients in HIIT exercised for 4×4 min at 85%-90% of HRpeak with 3-min recovery in between at 65%-75% of HRpeak. Results showed that HbA1c was reduced significantly from 8.2% (7.45%-8.65%) to 6.9% (6.6%-7.15%) in MICT and from 8.23% (7.94%-8.85%) to 6.25% (6.1%-6.89%) in HIIT after interventions. Likewise, eAG was significantly reduced from 188.64 mg/dL (167.11-201.55 mg/dL) to 151.33 mg/dL (142.72-158.50 mg/dL) in MICT and from 189.64 mg/dL (181.18-207.29 mg/dL) to 136.69 mg/dL (128.37-151.04 mg/dL) in HIIT. No significant difference was found between HIIT and MICT in the measured variables. It is concluded that the less physically demanding MICT is as good as HIIT for normalizing hyperglycemia in type 2 diabetic females. Therefore, recent interests surrounding HIIT should not overemphasize it compared to the traditional MICT for improving glycemic outcomes.