In a randomized controlled trial of 134 mildly stressed, middle-aged to older adults, participants who were assigned to a six-week mindfulness-meditation training program experienced significantly reduced negative affect variability—which refers to subjective distress and includes a range of mood states such as worry, anxiety, anger, self-criticism, and life dissatisfaction—compared with participants assigned to a waitlist control. The effects seen in the Stress & Health study were mediated by a reduction in perceived stress.
The findings support the theory that mindfulness training facilitates a capacity to observe and experience internal reactions to stressors as they arise with acceptance and equanimity. "In turn, this impartial receptiveness buffers initial threat appraisals, and subsequently, reduces emotional reactivity, potentially leading to greater health," the authors wrote.