How does stress (and rest) affect immune health?

When it comes to the immune system, the effects of stress cannot be overlooked. The immune system interacts with our hormonal regulation and our nervous system in ways that we’re only beginning to understand. In fact, some of the same biomarkers that are used to evaluate immune health (such as C-reactive protein and interleukins 6 & 8) are also considered to be biomarkers of chronic stress.^[1] Although exposure to certain types of stress can be healthy (exercise, adverse circumstances that make us stronger and more resilient), our stress-response is not designed to be activated all the time, and if it is, that can have negative effects on immune health. Chronic stress-induced increases in the hormone cortisol can suppress the immune system’s ability to fight off infection.^[2] Environmental stressors, such as pollution, may have similar immune-suppressing effects too.^[3] Some stress may be unavoidable, so getting adequate rest/recovery and managing the stress response can also be an effective approach for improving immune health.^[4] Mindfulness meditation may also improve immune biomarkers through managing the stress response.^[5] Similarly, immersion in nature and natural environments (like forests), also may enhance immune health, possibly through stress reduction.^[6][7] More high-quality evidence is still needed on many of these interventions, but based on what we know, any activity that optimizes our relationship with stress is likely to improve immune health in turn.