Effects of Supervised Short-Term Exercise Training On Cardiorespiratory Control and Exercise Capacity in Type 2 Diabetes Patients

Abstract

Objective: Type 2 diabetes is associated with impaired respiratory and cardiovascular control. Physical exercise training is a well-established tool in the treatment of diabetes. However, effects of short-term exercise training on respiratory control in diabetes are unknown. Thus, we examined the effects of 4 weeks of exercise training (high intensity interval- and continuous moderate exercise training; HIT and CMT) on cardiorespiratory control and aerobic capacity in type 2 diabetes subjects. Methods: Fifteen non-insulin dependent subjects with type 2 diabetes (4 female, 11 male, age 59.6 +/- 1.5 years, BMI 29.5 +/- 1.0 kg/m(2), HbA1C 7.0 +/- 0.3%) were randomized to either supervised HIT (N=8) or CMT (N=7), both equalized for the total amount of work, for 3 times a week over 4 weeks. At baseline and follow up, measurements of hypercapnic and hypoxic ventilatory response (HCVR; HVR), Baroreflex Sensitivity (BRS) and VO2 peak were performed. Results: Four weeks of supervised exercise training increased resting HCVR (from 0.55 +/- 0.1 to 0.73 +/- 0.1 L/min/mmHgCO(2-et)), whereas HVR and BRS remained unchanged. VO2 peak (27.5 +/- 1.4 versus 30.1 +/- 1.6 ml/kg/min) and VO2 at anaerobic threshold (19.7 +/- 1.0 versus 21.9 +/- 1.3 ml/kg/min) increased in the whole group. No significant changes between HIT and CMT were observed, except a slight increase in haemoglobin concentration after HIT. Conclusion: Our findings indicate that short-term exercise training increases HCVR associated with an improvement in aerobic capacity in patients with type 2 diabetes. HIT might demonstrate a less time demanding alternative to CMT. These findings are of clinical relevance, as exercise capacity predicts cardiovascular and overall mortality.