Physical Resilience in Older Adults: Systematic Review and Development of an Emerging Construct

Abstract

Background: Resilience has been described in the psychosocial literature as the capacity to maintain or regain well-being during or after adversity. Physical resilience is a newer concept that is highly relevant to successful aging. Our objective was to characterize the emerging construct of resilience as it pertains to physical health in older adults, and to identify gaps and opportunities to advance research in this area.

Methods: We conducted a systematic review to identify English language papers published through January 2015 that apply the term "resilience" in relation to physical health in older adults. We applied a modified framework analysis to characterize themes in implicit or explicit definitions of physical resilience.

Results: Of 1,078 abstracts identified, 49 articles met criteria for inclusion. Sixteen were letters or concept papers, and only one was an intervention study. Definitions of physical resilience spanned cellular to whole-person levels, incorporated many outcome measures, and represented three conceptual themes: resilience as a trait, trajectory, or characteristic/capacity.

Conclusions: Current biomedical literature lacks consensus on how to define and measure physical resilience. We propose a working definition of physical resilience at the whole person level: a characteristic which determines one's ability to resist or recover from functional decline following health stressor(s). We present a conceptual framework that encompasses the related construct of physiologic reserve. We discuss gaps and opportunities in measurement, interactions across contributors to physical resilience, and points of intervention.

Keywords: Disablement process; Frailty; Physical function; Physiology; Successful aging.

Figure 1.

Flow diagram for systematic review of English language medical literature using the term “resilience” in reference to physical health of older adults.

Figure 2.

Description of 49 articles identified in this review. This modified systematic review sought to identify biomedical, English language articles published through January 15, 2015 that applied the term “resilience” in relation to physical health in older adults. Panel A describes the geographic location (of the first author); Panel B notes the type of article or study. Panel C: 29 of 49 articles referenced a particular kind of exposure or intervention (ie, stressor) after which there may, or may not, be a resilient response. Some articles referenced multiple stressors. The stressors were categorized as psychosocial (eg, death of spouse), or physical (eg, heat exposure), or both (eg, Holocaust) and could be chronic (eg, high blood pressure) or acute events that happened remotely (eg, airplane crash years earlier) or recently (eg, hospitalization). Panel D: 27 articles referenced or assessed particular outcomes related to physical health including mortality, self-reported function, physical performance, physiological measures, quality of life, and falls. Some articles included multiple outcome measures.

Figure 3.

Proposed conceptual model of physical resilience. We propose that physical resilience at the whole person level, or one’s ability to resist decline or recover function following a stressor, is influenced by multiple factors, both internal and external to the individual. The white arrows represent several categories of presumed contributors to resilience, although this figure is not intended to provide an exhaustive list of contributors. Ultimately, the individual’s outcome is influenced by resilience as well as the magnitude and type of stressor. We suggest three potential strategies for quantifying the characteristic of “physical resilience” in future study, represented here as “windows” into the construct. Different measurement approaches may be more or less suitable depending on an investigator’s objectives and available data. For example, phenotypes and age discrepancy could theoretically be assessed by measurements taken at a single time point (cross-sectional) and without direct knowledge of the stressor, whereas quantifying resilience based on trajectories requires assessment at ≥2 time points and assumes a reasonably well-defined stressor.