Effects of 12 weeks of regular aerobic exercises on autonomic nervous system in obstructive sleep apnea syndrome patients

Introduction Regular exercise is confirmed as a lifestyle treatment option for all obstructive sleep apnea (OSA) patients. It has beneficial effects other than weight loss, although the mechanisms remain unclear. Autonomic function imbalance plays an important role in OSA, so that it is meaningful to observe the effect of exercise on autonomic function. Methods Seventy mild to moderate OSA patients were divided into two groups. The exercise group received a 12-week exercise program prescribed according to their first cardiopulmonary exercise tests, while the control group kept previous lifestyle. All patients underwent blood tests, cardiopulmonary exercise tests, and polysomnography studies at enrollment and at the 12-week's follow-up. Results At the end of 12 weeks, three patients of the exercise group did not complete the program due to lack of adherence. The current study showed 12-week aerobic exercises could improve body mass index (27.6 +/- 4.7 kg/m(2) vs. 24.5 +/- 4.2 kg/m(2), P < 0.05), exercise capacities, apnea-hypopnea index (total AHI 20.2 +/- 7.5 vs. 16.4 +/- 5.2, P < 0.05; supine AHI 22.1 +/- 6.3 vs. 18.3 +/- 4.9, P < 0.05), average oxyhemoglobin saturation (AverSpO2), time/percentage SpO2 below 90%, and heart rate recovery (HRR) of OSA patients. Moreover, AverSpO2 change was significantly associated with HRR change in the exercise group. Conclusions Our findings suggested regular aerobic exercise had beneficial effects on body mass index, functional capacity, intermittent hypoxia, and parasympathetic tone of OSA patients, and whether parasympathetic tone modification plays a role in improving intermittent hypoxia or not deserves further exploration.