RESUMO
Stressful situations lead to change in or damage to the central nervous system, the hypothalamic-pituitary-adrenal axis, and autonomic function. Techniques for reducing stress such as yoga and mindfulness meditation have been reported to improve emotional regulation and mindfulness skill, as well as stress response. Mindfulness skill relies on intense focus to quiet the mind and bring concentration to the present moment. The present study was a randomized control trial to investigate the effects of an 8-week training program (three 45-minute sessions/week, one session with an instructor and two sessions as home practice) in mindfulness meditation or in yoga on stress and related variables in healthy people. Forty-four healthy participants were randomly allocated to one of three groups: a mindfulness group (n = 16), a yoga group (n = 13), and a control group (n = 15). The yoga training significantly modified heart rate variability, contributing to decreased relative power of the low-frequency band; the relative power of the high-frequency band increased after training. The mindfulness meditation training significantly improved mindfulness skill and concentration performance. In the present study, yoga was associated with increased heart rate variability and mindfulness meditation was associated with an increase in mindfulness skill and concentration performance.