The growing popularity of meditation training to manage stress has contributed to a growing interest in the physiological mechanisms by which meditation may influence the body’s stress reaction. A systematic review and meta-analysis examined the results of randomized controlled trials that compared meditation interventions to active control groups.1 Forty-five studies were included. Meditation practices examined were focused attention, open monitoring and mantra repetition. Outcome measures studied were cortisol, blood pressure, heart rate, lipid and peripheral cytokine expression. Studies had diverse participants including healthy adults, undergraduate students, army soldiers, veterans, cancer survivors, and individuals with chronic pain conditions, cardiovascular disease, depression and hypertension.
When all meditation forms were analyzed together, meditation reduced blood cortisol, C-reactive protein, resting and ambulatory blood pressure, heart rate, triglycerides and tumor necrosis factor-alpha. The effect of meditation on:
- Cortisol and resting heart rate was considered to be high level of evidence.
- C-reactive protein, blood pressure, triglycerides and tumor necrosis factor-alpha was considered to be moderate level of evidence.
Analyzed individually:
- Open monitoring meditation reduced ambulatory systolic blood pressure, systolic blood pressure following a stress test and resting heart rate. Effects assessed as providing moderate level of evidence.
- Focussed awareness reduced blood cortisol and resting systolic blood pressure. Effects assessed as providing low level of evidence.
- Mantra repetition reduced systolic blood pressure. Effects assessed as providing low level of evidence.
Authors report the primary reason for downgrading the GRADE of evidence when analyzing meditation practices individually was the limited number of studies available and small sample sizes. They conclude overall, when compared to an active control (relaxation, exercise or education) meditation practice leads to decreased physiological markers of stress in a range of populations.
1Pascoe MC, Thompson DR, Jenkins ZM, Ski CF. Mindfulness mediates the physiological markers of stress: Systematic review and meta-analysis. J Psychiatr Res. 2017;95:156-78.