Abstract

As individuals age, they are at increased risk of experiencing health threats and loss of resources (Baltes et al., 1997; Heckhausen, Wrosch, & Schulz, 2010). Such age-related challenges can contribute to the experience of psychological distress and biological dysregulations, which in turn may instigate further deterioration of individuals’ physical health (Schulz, Martire, Beach, & Scheier, 2000; Wrosch, Schulz, & Heckhausen, 2004). However, theory and research also suggest that normative losses in older adults’ psychological, biological, and physical health can be circumvented if a person engages in adaptive self-regulation to address such age-related challenges (e.g., Baltes & Baltes, 1990; Carstensen et al., 1999; Hall, Chipperfield, Heckhausen, & Perry, 2010; Hamilton, Catley, & Karlson, 2007; Heckhausen & Schulz, 1995).
Using ideas from the Motivational Theory of Life-Span Development (Heckhausen & Schulz, 1995; Heckhausen, Wrosch, & Schulz, 2010), the three longitudinal studies of this dissertation extend prior lines of research by investigating whether the appropriate use of specific behavioral and cognitive self-regulation strategies can ameliorate age-associated losses among the elderly in general, and especially among “at-risk” individuals who confront adverse conditions (i.e., elevated stress or feelings of loneliness). The different studies are all based on the same multi-dimensional and multi-wave longitudinal dataset. While they address independent research questions, the nature of this dissertation creates some overlap in the reported procedures across studies.
Study 1 investigates the different roles of stress in the association between physical activity engagement and physical health among 157 older adults over four years of data collection. Results demonstrated that older adults’ physical health symptoms increased across time. In addition, older adults’ engagement in physical activity predicted a reduction of stress perceptions over two years and fewer physical health problems over four years among participants who perceived high levels of stress at baseline, but to a lesser extent among their counterparts who perceived low levels of stress at baseline. Finally, the long-term physical health benefits among highly stressed individuals were statistically mediated by a reduction of stress perceptions over two years. These findings suggest that physical activity has the potential to ameliorate chronically high perceptions of stress and thereby produce long-term benefits on older adults’ physical health.
Study 2 examines the long-term associations between reports of sleep duration and diurnal cortisol secretion over four years among 157 older adults. The study’s findings demonstrate that older adults experienced increases in diurnal cortisol secretion over time, and that this effect was forecasted by individual differences in sleep duration. Results from growth curve and cross-lagged panel analyses demonstrated that higher levels of and increases in sleep duration buffered long-term elevations of diurnal cortisol secretion. By contrast, lower levels of and declines in sleep duration predicted a steep increase in cortisol secretion over time. Reversed analyses indicated that diurnal cortisol secretion did not contribute to changes in sleep duration over time. These findings suggest that longer sleep exerts restorative functions and protects older adults from experiencing maladaptive increases in diurnal cortisol secretion over time.
Study 3 investigates in a sample of 122 older adults whether health-related self-protection (e.g., avoiding self-blame for health problems or seeing the silver lining) can predict psychological and biological benefits among lonely (as compared to non-lonely) participants. Results demonstrated that baseline self-protection predicted a reduction of psychological stress and diurnal cortisol volume over two years, and lower CRP after 6 years, but only among lonely participants. In addition, mediation analyses demonstrated that the observed short-term reduction of cortisol secretion mediated the effects of self-protective control on lower long-term levels of systematic inflammation. These findings suggest that lonely older adults may ameliorate stress-related psychological and biological disturbances if they engage in self-protection to cope with emerging health threats.
Overall, these findings contribute to our knowledge about pathways to healthy aging. The results are discussed in light of life-span theories of successful aging and general psychological models of health and disease. In addition, implications for clinical practice and future research are addressed.