Background:
Objective: The study examined diurnal regulation of salivary alpha-amylase (sAA) in association with daily stressors, adult day services (ADS) use, and other caregiving characteristics. Method: A sample of 165 family caregivers of individuals with dementia (IWD) completed an 8-day diary study. Caregivers provided 5 saliva samples across the 8 days. On some days, caregivers provided all or most of the care. On other days, their relative attended ADS for part of the day. A 3-level unconditional linear spline model was fit to describe the typical sAA diurnal rhythms. Predictors were then added to the unconditional model to test the hypotheses on ADS use and daily stressors. Results: Daily ADS use did not have an effect on diurnal sAA regulation. However, controlling for daily ADS use, greater ADS use over the 8 days was associated with a more prominent rise between 30 min after wake-up and before lunch, and a more prominent decline between before lunch and late afternoon. Fewer ADS days were associated with a more flattened sAA diurnal rhythm. Additionally, greater daily care-related stressor exposures had a within-person association with lower sAA levels in the late afternoon. Care-related stressor exposures had significant within- and between-person associations with sAA diurnal slopes. Furthermore, daily positive experiences had a significant between-person association with sAA diurnal slopes. Conclusions: Caring for a disabled family member may heighten the vulnerability to potential physiological conditions. Respite from care stressors from ADS use may have some biobehavioral benefits on sAA regulations.