Thomas M. Hess, Claire M. Growney, and Erica L. O'Brien
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Psychology. Please check back later for the full article.
The assessment of cardiovascular (CV) responses associated with behavioral phenomena has long been an important component of psychological research seeking to better understand the physiological underpinnings of behavior. Within the field of gerontology, there has historically been much interest in CV responses. Much of this work has focused on blood pressure as an important reflection of CV functioning that is relatively simple to assess. An examination of the gerontological literature reveals at least three different ways in which researchers have used blood pressure to examine aging-related processes. One approach is to use blood pressure as a measure of health, either in terms of the level of functioning of the CV system or as a reflection of various disease-related processes, and examine its relationship to other aspects of functioning. For example, blood pressure has been frequently examined in relation to cognitive decline. A second approach has been to examine blood pressure reactivity as a reflection of physiological responses to stress. Aging has been associated with higher levels of reactivity to the emotionally evocative, and thus an examination of normative changes in reactivity may be useful in understanding the impact of aging on the ability to deal with stress. Reactivity is also potentially useful in understanding the impact of stress on health, with high levels of reactivity along with high frequency of such incidences being associated with negative health outcomes. In the field of gerontology, the additional burden associated with elevated levels of reactivity in later life is of particular interest. Finally, recent work has also focused on blood pressure as a measure of an individual’s attempts to actively cope with challenging situations, broadly defined. Building off the active coping model of Obrist, blood pressure responses in a given situation are viewed as direct reflections of active coping as the cardiovascular system is energized to provide the resources needed by the body and nervous system to deal with a given situation. The level of response has been shown to reflect both the difficulty of the task and the individual’s motivation, and thus is a relatively reliable indicator of (a) an individual’s engagement in a particular task and (b) the resources necessary to perform that task. Recent work on aging has focused on the utility of this measure as a reflection of the costs associated with cognitive engagement and the extent to which variation in these costs might predict both between-individual and age-related normative variation in participation in cognitively demanding—but potentially beneficial—activities.
Stephanie J. Wilson, Alex Woody, and Janice K. Kiecolt-Glaser
Inflammatory markers provide invaluable tools for studying health and disease across the lifespan. Inflammation is central to the immune system’s response to infection and wounding; it also can increase in response to psychosocial stress. In addition, depression and physical symptoms such as pain and poor sleep can promote inflammation and, because these factors fuel each other, all contribute synergistically to rising inflammation. With increasing age, persistent exposure to pathogens and stress can induce a chronic proinflammatory state, a process known as inflamm-aging.
Inflammation’s relevance spans the life course, from childhood to adulthood to death. Infection-related inflammation and stress in childhood, and even maternal stress during pregnancy, may presage heightened inflammation and poor health in adulthood. In turn, chronically heightened inflammation in adulthood can foreshadow frailty, functional decline, and the onset of inflammatory diseases in older age.
The most commonly measured inflammatory markers include C-reactive protein (CRP) and proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). These biomarkers are typically measured in serum or plasma through blood draw, which capture current circulating levels of inflammation. Dried blood spots offer a newer, sometimes less expensive collection method but can capture only a limited subset of markers. Due to its notable confounds, salivary sampling cannot be recommended.
Inflammatory markers can be added to a wide range of lifespan developmental designs. Incorporating even a single inflammatory assessment to an existing longitudinal study can allow researchers to examine how developmental profiles and inflammatory status are linked, but repeated assessments must be used to draw conclusions about the associations’ temporal order and developmental changes. Although the various inflammatory indices can fluctuate from day to day, ecological momentary assessment and longitudinal burst studies have not yet incorporated daily inflammation measurement; this represents a promising avenue for future research.
In conclusion, mounting evidence suggests that inflammation affects health and disease across the lifespan and can help to capture how stress “gets under the skin.” Incorporating inflammatory biomarkers into developmental studies stands to enhance our understanding of both inflammation and lifespan development.
Idan Shalev and Waylon J. Hastings
Stress is a multistage process during which an organism perceives, interprets, and responds to threatening environmental stimuli. Physiological activity in the nervous, endocrine, and immune systems mediates the biological stress response. Although the stress response is adaptive in the short term, exposure to severe or chronic stressors dysregulates these biological systems, promoting maladaptive physiology and an accelerated aging phenotype, including aging on the cellular level. Two structures implicated in this process of stress and cellular aging are telomeres, whose length progressively decreases with age, and mitochondria, whose respiratory activity becomes increasingly inefficient with advanced age. Stress in its various forms is suggested to influence the maintenance and stability of these structures throughout life. Elucidating the interrelated connection between telomeres and mitochondria and how different types of stressors are influencing these structures to drive the aging process is of great interest. A better understanding of this subject can inform clinical treatments and intervention efforts to reduce (or even reverse) the damaging effects of stress on the aging process.