Posted 03.23.2016 | by AMRA
Heart disease is the largest cause of death among men and women in the United States. Lifestyle changes in smoking, diet, and exercise can help lower heart disease risk. Further, mindfulness has proposed stress-reducing effects and thus may have its own role to play in heart health.
In two separate studies, May et al. [Stress] examined the association between trait mindfulness and markers of cardiovascular health and state mindfulness and fluctuations in heart rhythm and blood pressure, which are modulated by the sympathetic nervous system. The sympathetic nervous system is the part of the nervous system responsible for the “fight-or-flight” stress response.
The studies employed two samples of predominantly female, Caucasian undergraduate students. All participants were assessed for self-reported trait mindfulness using the Mindful Attention Awareness Scale. In the first study, 185 participants had their cardiovascular functioning assessed by a computer-assisted method of estimating central blood pressure from peripheral arterial activity. The researchers used an estimate of central blood pressure because it is a better indicator of cardiovascular risk than the usual peripheral blood pressure measures obtained using a blood pressure cuff. This method also provided estimates of how hard the heart was working, how much oxygen it consumed, and how much blood it received through the cardiac arteries.
The first study found that while trait mindfulness wasn’t associated with blood pressure and heart rate, it was significantly associated with improved hemodynamic functioning in terms of decreased cardiac oxygen consumption and left ventricular workload. Simply put, the heart didn’t have to work as hard for those with higher levels of trait mindfulness.
In the second study, 124 participants were randomly assigned to either a mindfulness or a control intervention. In the mindfulness intervention, participants followed a 15-minute audiotaped guided mindfulness meditation focusing on the breath and bodily sensations in an effort to induce a state of mindfulness. Control participants were told to be silent and still for 15 minutes and relax.
Blood pressure variability and heart rate variability (fluctuations in the interval between heartbeats) were measured before and after the interventions. These are measures that are affected by sympathetic nervous system activity.
The second study found that the guided mindfulness meditation significantly lowered diastolic blood pressure (Cohen’s d = .39). It also decreased low-frequency oscillations in systolic (d = .47) and diastolic (d = .50) blood pressure, and low-frequency fluctuations in heart rate (d = 1.95). The term “low-frequency” refers to fluctuations of 0.04 to 0.15 oscillations per second. These results support the hypothesis that mindfulness decreases the effects of sympathetic nervous system activity on the heart: mindfulness decreased vagal tone, vasomotor tone, vascular resistance, and ventricular workload, resulting in an overall improvement in cardiovascular efficiency.
Taken together, these studies suggest that trait and state mindfulness both have roles to play in improving heart health by increasing the efficiency and reducing the workload of the cardiovascular system. Mindfulness-based interventions may be of potential benefit to patients with congestive heart failure and chronic hypertension, diseases with symptoms that are aggravated by sympathetic nervous system activity. This potential benefit is only speculative, as all of the participants in this study were young and healthy.
The studies are limited by the restricted sex, ethnicity, age, and health range of its participants, the brevity of its mindfulness training, and the fact that cardiovascular activity was observed over only a short period of time.
May, R. W., Bamber, M., Seibert, G., Sanchez-Gonzalez, M. A., Leonard, J. T., Salsbury, R. A., & Fincham, F. D. (2016). Understanding the physiology of mindfulness: Aortic hemodynamics and heart rate variability. Stress.