Rest-activity rhythms across the lifespan: cross-sectional findings from the US representative National Health and Nutrition Examination Survey

Abstract

Study objectives: Rest-activity rhythms (RAR) may mark development, aging, and physical and mental health. Understanding how they differ between people may inform intervention and health promotion efforts. However, RAR characteristics across the lifespan have not been well-studied. Therefore, we investigated the association between RAR measures with demographic and lifestyle factors in a US nationally representative study.

Methods: RAR metrics of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and mean amplitude and timing of high (M10) and low (L5) activity were derived from 2011 to 2012 and 2013 to 2014 National Health and Nutrition Examination Survey (NHANES) actigraphy data. Population-weighted linear and logistic regression models were fit to examine the associations of age, gender, smoking, alcohol, season, body mass index (BMI), income-to-poverty ratio, and race/ethnicity with RAR. Significance was based on a false-discovery rate-corrected P-value of <0.05.

Results: Among n = 12 526 NHANES participants (3-≥80 years), IS (higher = greater day-to-day regularity) and RA (higher = greater rhythm strength) generally decreased with age and were lower among males, whereas IV (higher = greater rhythm fragmentation) increased with age (p < 0.05). Dynamic changes in RAR trajectories were observed during childhood and adolescence. Income, BMI, smoking, and alcohol use were associated with RAR metrics, as well as season among children and teenagers (p < 0.05). RAR also differed by race/ethnicity (p < 0.05), with trajectories initially diverging in childhood and continuing into adulthood.

Conclusions: RAR differed by demographic and health-related factors, representing possible windows for public health intervention and sleep health promotion. RAR differences by race/ethnicity begin in childhood, are evident in early adolescence, and persist throughout adulthood.

Keywords: actigraphy; adolescent; adult; aged; child; circadian; sleep.

Graphical abstract

Figure 1.

Flow chart depicting sample sizes of participants included in the analyses.

Figure 2.

Plots of Interdaily stability (IS, purple), Intradaily variability (IV, magenta), and relative amplitude (RA, blue) by gender (solid line = women, dashed line = men) across ages 3–80 in NHANES 2011–2014.

Figure 3.

Circular plot of the start time of the 10 hours of highest activity (M10) for ages (A) 3–5 years old (n = 398) (B) 6–12 years old (n = 2281) and (C) 13–19 years old (n = 1591) and the start time of the 5 hours of lowest activity (L5) for ages (D) 3–5 years old (E) 6–12 years old and (F) 13–19 years old in NHANES. The arrows on the clockface represent the circular mean of the M10 and L5 times by age group.

Figure 4.

Plots of (A) interdaily stability (IS), (B) intradaily variability (IV), and (C) relative amplitude (RA) by race/ethnicity and gender as measured by actigraphy across ages 3–80 in NHANES 2011–2014. Solid line = women, dashed line = men, orange = Mexican-American, purple = NH Asian, sky blue = NH Black, dark blue = NH White, pink = Other/Multiracial, red = Other Hispanic.