Exercise training on chronotropic response and exercise capacity in patients with type 2 diabetes mellitus

The study was designed to observe the effects and relationship of exercise on chronotropic response (CR) and exercise capacity in patients with type 2 diabetes mellitus (T2DM). A total of 30 patients with T2DM underwent symptom-limited cardiopulmonary exercise testing (CPET) after excluding contraindication. For each subject individualized exercise prescription was formulated, and they received 12 weeks of exercise training after CPET retest to complete the comparison of CR indicators, including the ratio of maximum exercise heart rate to predicted maximum heart rate value (rHR), heart rate reserve rate (HRRes), heart rate recovery (HRR) of 1-6 min after exercise termination (HRR1-6), exercise capacity (peak VO2/kg) and other indicators. The results showed that after 12 weeks of exercise treatment, rHR, HRRes, HRR1-6, and peak VO2/kg were significantly higher than before (P<0.05), with peak VO2/kg being positively correlated to rHR and HRRes (P<0.01). In conclusion, exercise training can improve cardiac dysfunction, abnormal HRR, enhance exercise capacity and adaptability of the cardiovascular system to exercise stress in T2DM patients.