Introduction

There has been much interest in heart rate dynamics during a variety of physiological and pathological states. In addition, considerable attention has been focused on the potential health benefits of a variety of meditative, relaxation techniques and their possible effects on neuroautonomic function. Surprisingly, however, there is little information regarding the effects of meditation on beat-to-beat heart rate dynamics as an indirect ``assay'' of autonomic regulation [1,2,3]. Accordingly, we collected and analyzed continuous heart rate time series from two groups of healthy young adults before and during two well-known forms of meditation. We sought to determine 1) whether there are any distinctive heart rate dynamics during these practices, and 2) whether such meditative states induce a quiescent (less variable) or active (more variable) pattern of autonomic response.