Effects of respiratory muscles training on vascular function

Aim: Respiratory muscles training (RMT) leads to a decrease in sympathetic drive and to a subsequent drop in systolic and diastolic blood pressure. This may improve vascular function. However, scientific evidence is actually lacking about the effects of RMT on vascular function. Methods: Eighteen physically active participants (5 males and 13 females) were randomly assigned to a training group (TG: age 27±8, BMI 24±4; RMT 3 times a week for 2 months) or to a sham group (SG: age 34±15, BMI 24±4; 8 weeks of RMT familiarization) after 1 week of familiarization. Maximal inspiratory mouth pressure (MIP) and maximum voluntary ventilation (MVV) were utilized to assess the effects of RMT. Heart rate variability (HRV) defined the activity of autonomic nervous system. Vascular function was assessed by pulse wave velocity (PWV), flow mediated dilation (FMD) and carotid lumen diameter (cLD) through ultrasound measurements. Results: After 8 weeks, MIP and MVV increased by ~40% and ~9%, respectively, in TG (P<0.05), but not in SG. However, no differences were found in HRV parameters and in PWV, FMD, cLD values after RMT. Conclusion: Despite a significant effect on MIP and MVV, data from the current study indicate a not detectable effect of RMT on vascular function. Therefore, the increase in respiratory function didn’t induce changes in vascular function, likely because of the normal sympathetic drive and normal blood pressure of the selected participants. Further studies on hypertensive individuals may be required to disclose RMT effects on vascular function.