Profiles of Accelerometry-Derived Physical Activity Are Related to Perceived Physical Fatigability in Older Adults

Abstract

Physical activity (PA) is associated with greater fatigability in older adults; little is known about magnitude, shape, timing and variability of the entire 24-h rest–activity rhythm (RAR) associated with fatigability. We identified which features of the 24-h RAR pattern were independently and jointly associated with greater perceived physical fatigability (Pittsburgh Fatigability Scale, PFS, 0–50) in older adults (n = 181, 71.3 ± 6.7 years). RARs were characterized using anti-logistic extended cosine models and 4-h intervals of PA means and standard deviations across days. A K-means clustering algorithm approach identified four profiles of RAR features: “Less Active/Robust”, “Earlier Risers”, “More Active/Robust” and “Later RAR”. Quantile regression tested associations of each RAR feature/profile on median PFS adjusted for age, sex, race, body mass index and depression symptomatology. Later rise times (up mesor; β = 1.38, p = 0.01) and timing of midpoint of activity (acrophase; β = 1.29, p = 0.01) were associated with higher PFS scores. Lower PA between 4 a.m. and 8 a.m. was associated with higher PFS scores (β = −4.50, p = 0.03). “Less Active/Robust” (β = 6.14, p = 0.01) and “Later RAR” (β = 3.53, p = 0.01) patterns were associated with higher PFS scores compared to “Earlier Risers”. Greater physical fatigability in older adults was associated with dampened, more variable, and later RARs. This work can guide development of interventions aimed at modifying RARs to reduce fatigability in older adults.

Age Is Associated With Dampened Circadian Patterns of Rest and Activity: The Study of Muscle, Mobility, and Aging (SOMMA)

“…Specifically, rest-activity data obtained from such monitors worn for several consecutive days, can be mathematically assessed for a daily circadian rhythm; and the shape of these rhythmic patterns may reveal insight into health and disease status. For example, a remarkably consistent observation across numerous cohort studies is that a dampened rhythmic amplitude is associated with age-related chronic conditions and pathologies, including changes in cognitive functioning, signs of Alzheimer's disease, fatigue, markers of inflammation, reduced cardiometabolic and bone health, and even mortality (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

Age is Associated with Dampened Circadian Patterns of Rest and Activity: The Study of Muscle, Mobility and Aging (SOMMA)

“…Specifically, rest-activity data obtained from such monitors worn for several consecutive days, can be mathematically assessed for a daily circadian rhythm; and the shape of these rhythmic patterns may reveal insight into health and disease status. For example, a remarkably consistent observation across numerous cohort studies is that a dampened rhythmic amplitude is associated with age-related chronic conditions and pathologies, including changes in cognitive functioning, signs of Alzheimer’s disease, fatigue, markers of inflammation, reduced cardiometabolic and bone health, and even mortality (10–20). While these relationships between altered rest-activity rhythms and disease outcomes are striking, what remains unaddressed is the impact of aging itself on rest-activity patterns.…”