Mindfulness mediates the physiological markers of stress

This is an invited research digest contributed by Dr. Michaela C. Pascoe of Australian Catholic University.

Meditation is a popular form of stress management, and some research shows that it can be helpful in decreasing how stressed we feel when faced with challenges. Many of these studies that have looked at physiological markers of stress both before and after meditation training have not included a control group, and therefore it is difficult to know if it is the meditation training specifically resulting in improved stress management. Perhaps just being enrolled in a study makes people think about stress management and that helps, regardless of what intervention they are receiving.   

 It is important to validate if meditation is effective in meditating stress-reactivity using studies with a control group. Therefore in our meta-analysis, we collected data from randomised control trials of mediation versus an active control group on markers of stress. Randomised control trials are studies where participants can be randomly assigned to either the meditation or a control group, such as aerobic exercise or education. Randomised control trials are considered to provide reliable scientific evidence when well conducted, and examining data from a number of these, as is done with a meta-analysis, can provide reliable evidence. 

 We extracted data from randomised control trials and looked at the effect of different mediation forms on markers of stress, compared to the active control groups. The meditation forms were open monitoring, focused attention and automatic self-transcending meditation.

Open monitoring or mindfulness-based meditation involves non-reactive observation of the content of ongoing experience, to become reflectively aware of cognitive and emotional patterns.  In focused attention meditation, attention is focused and sustained on a particular object and brought back to the object when the mind has wandered. Thus, the meditator is controlling one’s own attention. Automatic self-transcending meditation involves a meaningless mantra that the meditator can attend to without effort or concentration, with the aim of the mantra becoming secondary and ultimately disappearing as self-awareness increases. In automatic self-transcending meditation the mind should be free from focus and mental effort.

We included forty-five randomized control trials in our analysis. We found that focused attention and automatic self-transcending meditation subtypes reduced systolic blood pressure, which was considered low level scientific evidence, which means that the findings should interpreted with caution and that more research needs to be conducted to confirm or refute the findings. Focused attention meditations additionally reduced cortisol, also considered low level evidence and open monitoring meditations reduced heart rate, which was considered moderate level evidence, which means that we can have more faith that the finding is accurate however there are still limitations. Therefore, the evidence for the benefit of open monitoring meditation is higher than the level of evidence for focused attention and automatic self-transcending meditation subtypes and further research should be conducted to confirm or refute these findings. Therefore, while these results are promising, further research should be conducted in terms of how different mediation subtypes influence what markers of stress.

Editor’s Comment

This is a research digest of a recent meta-analysis. Meta-analysis is a statistical method that synthesizes findings from multiple studies and generalizes results to a larger population. Meta-analysis provides the soundest scientific evidence. The highlight of this meta-analysis is the inclusion of studies that used active control groups such as aerobic exercise or education. Thus, any significant effect of meditation will reveal its benefits beyond engaging in aerobic exercise or receiving educational lectures. This meta-analysis by Dr. Michaela C. Pascoe did find this kind of significant effects, suggesting robust stress-reducing powers of meditation. Of note, open monitoring or mindfulness-based meditation had the highest level evidence. You can learn more about mindfulness by taking an online test.

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