Chronic stress undermines health by increasing inflammation throughout the body, increasing the risk for heart disease, cancer, arthritis, and Alzheimer’s disease, among others. A pair of studies, published in PLOS ONE, find that mindfulness practice may help lessen this risk in those most vulnerable to stress: midlife-to-older adults, and those with a high body mass index (BMI).
The first study included 153 people between the ages of 18 and 70 who reported moderate to high levels of stress. Each was randomly assigned to one of three groups: Monitor+Accept training, Monitor Only instruction, and a stress management program control group.
Monitor+Accept training focused on monitoring present-moment experiences, like physical sensations and emotions, and “welcoming and accepting” them. The Monitor Only program also emphasized paying attention to experiences in the present, but did not include teachings about acceptance. The stress management program taught coping strategies like reappraising thoughts, and practicing skills for solving personal problems.
Participants in each group listened to a 20-minute recording plus three- to ten-minute practices on their smartphones each day. They also provided blood samples before and after the two weeks of training to test for changes in C-Reactive Protein (CRP), a commonly measured biomarker of inflammation. (Research convincingly shows that chronically stressed people have higher levels of CPR compared to those who aren’t stressed, which places them at greater risk for illnesses like cardiac disease, diabetes, arthritis, and dementia.)
Mindfulness practice lowers stress biomarkers for older and overweight adults
Results of the first study showed no differences in CRP after two weeks of training for either of the three groups. The researchers concluded that two weeks of meditation may not have been enough to lower biological stress markers. Researchers conducted a second study where they assigned a new sample of 137 adults to either a Monitor+Accept course based on mindfulness-based stress reduction (MBSR), a MBSR-based program focusing on monitoring only, or a no training control group.
This time the MBSR-based programs involved eight weekly, two- to three-hour-long in-person sessions, as well as a day-long retreat and approximately 45 minutes of daily meditation practice. Members of all three groups provided blood samples at the beginning of the study, then again eight weeks later. As in the first study, the groups who practiced meditation showed little change in the inflammatory biomarker CRP compared to the control group.
Mindfulness practice was not directly linked to lower inflammation levels, but may have bolstered stress resilience among at-risk adults by preventing an increase in inflammatory biomarker levels.
This led researchers to examine whether adults classified as overweight or obese by the CDC (BMI greater than or equal to 25), or those over age 45 (both of whom generally have higher levels of CRP than younger adults and those with a BMI of less than 25), might be more positively impacted by meditation practice. They combined the data from the first and second studies, and compared results of younger adults with those aged 45 and older. They then compared results of adults with a higher BMI to those with a BMI of less than 25.
How mindfulness reduces biological damage from stress
What they found was that older adults in the control groups of both the two- and eight-week studies had higher levels of CRP compared to those who attended the mindfulness programs. There were no differences in CRP levels between the mindfulness training groups. This suggests that mindfulness practice was not directly linked to lower inflammation levels, but that it may have bolstered stress resilience among at-risk adults by preventing an increase in inflammatory biomarker levels.
The picture for overweight or obese adults was slightly different. In both studies, participants in both meditation groups showed decreases in CRP following training, while control group members showed an increase. Again, there were no differences between the Monitor+Accept and Monitor only groups.
Authors of the studies concluded that, while mindfulness meditation programs may not lead to the significant decrease of inflammatory biomarkers in all adults, stressed older adults or those with a higher BMI may experience some health benefits from mindfulness training.