Physically active individuals have lower rates of morbidity and mortality, and recent evidence indicates that physical activity may be particularly beneficial to those experiencing chronic stress. The tendency to ruminate increases and prolongs physiological stress responses, including hypothalamic-pituitary-adrenal (HPA) axis responses as indexed by cortisol reactivity to stressful experiences. We examined the association between ruminating in response to a laboratory stressor task and HPA axis reactivity and recovery and examined whether a physically active life-style moderates the associations between rumination and cortisol output trajectories.
Forty-six postmenopausal women underwent the Trier Social Stress Test, whereas salivary cortisol was repeatedly measured. Twenty-five minutes after the end of the stressor, participants reported level of rumination in response to the stress.
Findings indicate that physical activity moderated the initial rate (B = −0.10, standard error = 0.04, p < .05) and curvature (B = −0.03, standard error = 0.01, p = .06) of the relationship between rumination and log-transformed cortisol trajectory. Among sedentary participants, those who responded to the stressor with higher levels of rumination had a more rapid initial increase in cortisol level (0.26 versus 0.21, p < .001), a later peak in cortisol reactivity (56 versus 39 minutes), and a delayed recovery from stress (curvature: −0.07 versus −0.08, p < .001) compared with those with lower levels of rumination. In active participants, cortisol trajectories were equivalent, regardless of the level of rumination.
In sum, individuals who maintain a physically active life-style may be protected against the effects of rumination on HPA axis reactivity to and recovery from acute stress.
HPA = hypothalamic-pituitary-adrenal; TSST = Trier Social Stress Task; RRS = Ruminative Responses Scale; BMI = body mass index; REML = restricted maximum likelihood; HRT = hormone replacement therapy.
From the Department of Psychiatry (E.P., A.O., N.E.A., M.K., O.M.W., E.E.), University of California, San Francisco; San Francisco Veteran's Affairs Medical Center (A.O.), San Francisco, California; and Departments of Psychology and Nutrition (A.J.T.), Rutgers University, New Brunswick, New Jersey.
Address correspondence and reprint requests to Eli Puterman, PhD, Department of Psychiatry, University of California, 3333 California Street, Suite 465, San Francisco, CA 94118. E-mail: firstname.lastname@example.org
The research study was supported by the Division of Behavioral and Social Research at the National Institute on Aging/National Institutes of Health R56 Grant (E.E.). The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health.
Received for publication August 31, 2010; revision received May 5, 2011.