Dispositional mindfulness and cardiovascular reactivity to sensory rejection and sensory intake tasks.

摘要

Mindfulness is a trained or dispositional state of "being" that has been linked to positive mental and physical health effects. Although preliminary findings on cortical activation have shown mindfulness to be associated with increased frontal activation and reduced limbic activity, very little is known regarding the influence of mindfulness on autonomic nervous system activity. The present study sought to determine how participants varying in self-reported levels of dispositional mindfulness reacted to tasks differing on attention to environmental stimuli. Cardiovascular reactivity [heart rate, heart rate variability (HRV), and systolic and diastolic blood pressure] to a sensory intake task (computerized reaction time task) was contrasted with reactivity to a sensory rejection task (mental arithmetic). Forty students (71% women) were selected from a large sample of undergraduates and categorized as being high or low in dispositional mindfulness. Congruent with previous research, heart rates increased during the sensory rejection task and decreased during the sensory intake task (p < .01). Additionally, significant differences between tasks were observed for high and low frequency HRV, with heart rate increases to sensory rejection being associated with increased low frequency HRV and heart rate decreases to sensory intake being associated with increased high frequency HRV (ps < .001). Though the proposed Mindfulness Level by Task Type interaction was not significant, results showed that systolic blood pressure reactivity differed between high and low levels of mindfulness (p < .01), with higher systolic blood pressure reactions being associated with high levels of mindfulness. Further examination of mindfulness factors revealed that the Act with Awareness facet of mindfulness was significantly related to blood pressure reactivity during the sensory intake task, but not during the sensory rejection task, r's = .40--.48, p's <.01. Results also revealed that participants high in mindfulness performed much better on the sensory intake task than participants low in mindfulness, but these task performance differences did not explain the elevated blood pressure responses observed among high mindfulness participants. These results replicate and extend existing research reporting task differences in cardiovascular reactivity, indicating that reactivity to sensory rejection tasks is driven by the sympathetic nervous system, whereas reactivity to sensory intake tasks is primarily parasympathetic. Results relating mindfulness and reactivity to stress imply that acting with awareness may be one behavioral mechanism through which dispositional mindfulness influences physiology.