Stress-buffering effects of volunteering on salivary cortisol: Results from a daily diary study.

Based on the theoretical foundations of the caregiving system model, which holds that prosocial behavior can be conceptualized in relation to a neurobiological stress-buffering mechanism, we addressed the question of whether daily volunteering yields buffering effects in terms of suppressing a neuroendocrine response (i.e., salivary cortisol) to daily stressors. We used daily diary data from the second wave of the National Study of Daily Experiences (NSDE II), which is part of the Midlife in the United States study (MIDUS II), a nationally representative survey of middle-aged and older adults. Analyzing a sample of volunteers (N = 340), we tested the buffering role of daily volunteer work for the same day stressors-salivary cortisol response relationship (person-day observations, N = 1,042). Findings from multilevel models indicated that the relationship between daily stressors and cortisol output was attenuated on days when volunteering was performed compared to days volunteering was not performed. Our findings are suggestive of a unique, but unobserved, neurobiological mechanism underlying the link between volunteering and better health. Volunteer programs designed to help others in need may be considered as an intervention strategy for individuals living under stressful conditions.