Reduced stress and inflammatory responsiveness in experienced meditators compared to a matched healthy control group

Abstract

Psychological stress is a major contributor to symptom exacerbation across many chronic inflammatory conditions and can acutely provoke increases in inflammation in healthy individuals. With the rise in rates of inflammation-related medical conditions, evidence for behavioral approaches that reduce stress reactivity is of value. Here, we compare 31 experienced meditators, with an average of approximately 9000 lifetime hours of meditation practice (M age=51years) to an age- and sex-matched control group (n=37; M age=48years) on measures of stress- and inflammatory responsivity, and measures of psychological health. The Trier Social Stress Test (TSST) was used to induce psychological stress and a neurogenic inflammatory response was produced using topical application of capsaicin cream to forearm skin. Size of the capsaicin-induced flare response and increase in salivary cortisol and alpha amylase were used to quantify the magnitude of inflammatory and stress responses, respectively. Results show that experienced meditators have lower TSST-evoked cortisol (62.62±2.52 vs. 70.38±2.33; p<.05) and perceived stress (4.18±.41 vs. 5.56±.30; p<.01), as well as a smaller neurogenic inflammatory response (81.55±4.6 vs. 96.76±4.26; p<.05), compared to the control group. Moreover, experienced meditators reported higher levels of psychological factors associated with wellbeing and resilience. These results suggest that the long-term practice of meditation may reduce stress reactivity and could be of therapeutic benefit in chronic inflammatory conditions characterized by neurogenic inflammation.

Keywords: Alpha amylase; Cortisol; HPA-axis; Inflammation; Stress.

Figure 1

Group difference in covariate (age & sex) adjusted mean log cortisol AUC (top; F(1, 59) = 5.03, p = .029 ) and flare peak (bottom; t(64) = 2.41, p = .019). Note that with removal of the one extreme low and one extreme high value in flare peak in the LTM group, the group difference remains significant (t(62) = 2.58, p = .012).

Figure 2

Residual variance in maximum percent increase in cortisol (x-axis) and flare AUC response (y-axis) with variance accounted for by age, sex, perceived stressfulness of TSST, and group removed (ß = .28, sr = .26, p = .039). Red = LTM, blue = MNP.

Figure 3

Correlation between maximum percent increase in cortisol and perceived stressfulness of TSST in LTMs (right) and MNPs (left). This relationship is significant across groups (r = .36, p = .007) and for the LTM group alone (r = .50, p = .009), but not for the MNP group alone (r = .24, p = .21). The difference in the correlation between groups is not significant.