The influence of physical activity level on heart rate variability among asthmatic adults

Aims: The aim of the study was to evaluate the impact of physical activity levels on heart rate variability among asthmatic patients. Background: In recent years, heart rate variability is frequently used to assess the autonomic nervous system. The pathogenesis of asthma is probably related to autonomic dysfunction. Adequate exercise is considered beneficial to patients who suffer from asthma. However, the relationship between physical activity and the autonomic nervous system of adult asthmatic patients is still unknown. Design: A cross-sectional survey. Methods: A total of 54 subjects (27 healthy persons and 27 asthmatic patients matched by age and gender) were recruited for this study. Heart rate variability was determined by frequency analysis and measured in both resting and active states. The Seven-Day Physical Activity Recall was used to determine the subject's amount of weekly activity. Results: The results showed that the total power, low frequency (ms²), low frequency (nu) and low frequency/high frequency (nu) but not high frequency (nu) were significantly higher in healthy adults compared to asthmatic patients, no matter whether resting or exercising. In both groups, the greater the amount of moderate-to-vigorous physical activity, the higher the TP observed. However, a positive relationship between the amount of moderate-to-vigorous physical activity and low frequency (nu) and a negative relationship with high frequency (nu), respectively, was demonstrated only in asthmatic patients. There was no significant difference in heart rate variability between the asthmatic patients who engaged in more moderate-to-vigorous physical activity and the healthy patients. Conclusions: Although the asthmatic patients had poor heart rate variability compared with healthy people, engaging in higher amounts of moderate-to-vigorous physical activity may result in a heart rate variability similar to that of healthy people. Relevance to clinical practice: The results of this study suggest that healthcare professionals should encourage asthmatic patients to take as much physical exercise as they can in their daily lives.