Cortisol is a biomarker of stress reactivity, and its diurnal pattern is an indicator of general neuroendocrine health. Despite theories conceptualizing marital dyads as dynamic systems wherein spouses are interdependent in their physiology and stress coping, little is known about the daily processes in which spouses possibly influence each other in biological stress. Nineteen heterosexual couples provided saliva samples containing cortisol 4 times a day for 4 consecutive days. We used multilevel modeling to examine whether one’s cortisol awaking response (CAR) and diurnal cortisol slope (DCS) predict those of the spouse’s on the same day and/or on the next day. We found that spouses synchronize their DCS, such that on days when one experiences faster or slower decline in diurnal cortisol than usual, the spouse also experiences faster or slower decline than usual. For CAR, positive synchrony was only observed in couples reporting high levels of marital strain and disagreement. Cross-lagged regression analysis reveals stability in diurnal cortisol pattern. A steeper cortisol slope on a particular day predicts a steeper slope on the next day within an individual, but no significant cross-lagged relation was found between spouses. Couples reporting more spousal support tend to have stronger stability in CAR. These findings provide evidence that spouses are interdependent in their diurnal cortisol patterns on a day-to-day basis, and that these daily dynamics are associated with marital relationship quality. The study contributes to our understanding of marital processes and biobehavioral health. It also contributes methodologically to the advancement of longitudinal dyadic analysis. (PsycINFO Database Record (c) 2013 APA, all rights reserved)
PURPOSE: This study examined links between diurnal patterns of the stress hormone cortisol and time spent by adolescents in nine common daily activities.
METHODS: During eight consecutive nightly telephone interviews, 28 youths (n = 12 girls), 10-18 years of age, reported their daily activities. On 4 days, four saliva samples were also collected and assayed for cortisol. Multilevel models assessed within- and between-person associations between time in each activity and cortisol area under the curve (AUC), cortisol awakening response (CAR), morning peak (30 minutes after wake up), and daily decline (morning peak to bedtime).
RESULTS: Links with AUC were found for most activities; significant associations with cortisol rhythms suggested that most effects were due to anticipation of the day's activities. Specifically, on days when youths spent more time than usual on video games and television, they had lower AUCs, with lower morning peaks. Youths who spent more time reading (within-person) and in computer-related activities (between-person) had higher AUCs, with stronger CARs (within-person). Youths who slept more had lower AUCs, with lower morning peaks on both the between- and within-person levels. Amounts of time spent in clubs, and for older adolescents in sports, were also linked to lower AUCs. Finally, youths who spent more time in school/schoolwork had lower average AUCs, but on days when youths spent more time than usual in school, they had higher AUCs, stronger CARs, and steeper daily declines.
CONCLUSION: Beyond their known implications for psychological adjustment, youths' everyday activities are linked to stress physiology.