Improving heart rate variability (HRV) by non- pharmacological techniques

Sir, We read with interest the excellent article of Sztajzel J [1]. It is an important and carefully reviewed article which illustrates the various techniques for measurement of heart rate variability (HRV) and its clinical applications. We would like to suggest that there are also a number of non-pharmacological techniques for improvement of HRV, such as thought field therapy [2], aerobic training [3], biofeedback [4], yoga [5], abdominal breathing [6], qigong breathing [7], and meditation. These techniques are believed to stabilise the autonomic nervous system by modulating the parasympathetic nervous system and in turn improve HRV. As reduced HRV is associated with increased risk of cardiac and overall mortality and the occurrence of life-threatening arrhythmias, long term studies are needed to determine the impact of these techniques on HRV and whether this is of therapeutic value in patients with reduced HRV.