Prolonged psychological stress can induce a state of chronic low-grade systemic inflammation. Inflammation, in turn, can contribute to the onset or worsening of many physical and mental conditions. Mindfulness-based interventions that reduce stress may also help reduce systemic inflammation.

The body’s inflammatory response is a complex process that involves the activation of immune system cells and the release of proteins known as cytokines. Different cytokines can promote or inhibit inflammation. 

Gardi et al. [Psychoneuroimmunology] tested the effects of a 3-day resort-based mindfulness meditation retreat compared to a vacation retreat on perceived stress, stress hormones, and cytokine levels.

The researchers randomly assigned 95 healthy Italian adults (average age = 47 years; 51% male) to a 3-day intensive mindfulness retreat or a 3-day vacation control. The retreat and vacations were held at the same resort. The mindfulness retreat involved 10-hours a day of alternating sitting and walking meditation taught by experienced meditation teachers. Meditations involved attention to and acceptance of the breath, physical sensations, thoughts, and feelings. 

The vacation retreat involved unstructured free time allowing participants to rest, walk in nature, read, or socialize with others. 

Participants were assessed before and after the 3-day interventions on self-report measures of perceived stress, anxiety, and mindfulness (using the Mindful Attention Awareness Scale) and provided one saliva sample between 5:00-6:00 AM upon awakening before and after retreat.

Saliva samples were assayed for levels of cortisol (a stress hormone) and a panel of pro- and anti-inflammatory cytokines (IL-2, IL-4, IL-6, IL-8, IL-10, IFN- γ, TNF-α, and GM-CSF). Only cortisol and cytokines IL-6, IL-8, and IL-10 were detectable and included in subsequent analyses.

The results showed while both groups reduced perceived stress, only the mindfulness group exhibited significantly decreased anxiety, increased mindfulness, decreased levels of cortisol and pro-inflammatory IL-6 and IL-8, and increased levels of anti-inflammatory IL-10 after the retreat.

Salivary cortisol levels were highly correlated with anxiety and stress in both groups. For example, before the retreat salivary cortisol correlated with anxiety (r=.64) and with perceived stress (r=.98) within the mindfulness group. Similar large correlations were obtained for the vacation group, and for both groups following the retreat.

This is the first study to show a saliva-based anti-inflammatory effect of an intensive mindfulness retreat in a healthy sample. The salutary effects of a 3-day mindfulness retreat were beyond those of 3 days of vacationing.

Salivary cytokine levels differ from blood serum cytokine levels, thus the study is limited when inferring to systemic inflammation. Although correlations between cortisol and stress are quite high in this study, single measures of morning salivary cortisol are not generally considered to be reliable measures of physiological stress.

Reference:

Gardi, C., Fazia, T., Stringa, B., & Giommi, F. (2022). A short Mindfulness retreat can improve biological markers of stress and inflammation. Psychoneuroendocrinology, 135, 105579. 

Link to study