Abstract
Research has shown that asthmatics have a diminished autonomic nervous system as a result of increased hyperactivity to the vagal nerve, and is reflected in changes in heart rate variability. Yoga is a form of relaxation and exercise which has been proven to improve heart rate variability in the healthy population as well as in asthmatics during acute bouts.
PURPOSE: To assess whether ten weeks of yoga training can improve heart rate variability as well as quality of life in asthmatics.
METHODS: Twenty individuals were randomly assigned to either a yoga group or a control group for ten weeks. All subjects answered the St.George's Respiratory Quality of Care Questionnaire to assess quality of life and performed autonomic function tests (handgrip (3 min at 30% maximal voluntary contraction) and upright tilt (5 min at 80°, paced breathing))to assess heart rate variability changes prior to and after the training period. Oxygen consumption and ventilation during the tasks were also assessed.
RESULTS: The yoga group demonstrated a significant decrease in HFnu pre to post (.449 ±.60 vs..347 ±.059, p<.05, respectively), during the handgrip task whereas the control group did not change. There was a main effect of time for LFnu pre to post (.474 ±.059 vs..552 ±.059, p<.05, respectively) and logLF/HF pre to post (4.66 ±.308 vs. 5.041 ±.303, p<.05, respectively) during handgrip exercise. Significant improvements were also evident in the yoga group post training for the quality of life questionnaire (p<.05), in that the yoga group improved by 42.5%. There were no significant differences in heart rate variability during the upright tilt as well as no differences in oxygen consumption or ventilation during either task.
CONCLUSIONS: Ten weeks of yoga training decreases hyperactivity of the vagal nerve during the handgrip test and this is evident by an improvement in quality of life in asthmatics