24-h Activity Rhythms and Health in Older Adults

Abstract

Purpose of Review Circadian rhythms, including 24-h activity rhythms, change with age. Disturbances in these 24-h activity rhythms at older age have also been implied in various diseases. This review evaluates recent findings on 24-h activity rhythms and disease in older adults. Recent Findings Growing evidence supports that 24-h activity rhythm disturbances at older age are related to the presence and/or progression of disease. Longitudinal and genetic work even suggests a potential causal contribution of disturbed 24-h activity rhythms to disease development. Interventional studies targeting circadian and 24-h activity rhythms demonstrate that 24-h rhythmicity can be improved, but the effect of improving 24-h rhythmicity on disease risk or progression remains to be shown. Summary Increasing evidence suggests that 24-h activity rhythms are involved in age-related diseases. Further studies are needed to assess causality, underlying mechanisms, and the effects of treating disturbed 24-h activity rhythms on age-related disease.

Light in the Senior Home: Effects of Dynamic and Individual Light Exposure on Sleep, Cognition, and Well-Being

“…Our results confirm that circadian rhythms in senior home residents are highly disturbed, with greater disturbance in cognitively impaired residents [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Consistent with previous research [ 22 , 23 , 24 , 25 , 26 ], our sample had phase advanced and low amplitude rest–activity rhythms that were highly fragmented (high IV) and variable over time (low IS).…”

“…Circadian rhythm disturbances and poor sleep have been linked to cognitive decline and poor health in older adults [ 28 ]. Compared to age-matched healthy adults, patients with dementia have a more fragmented and lower amplitude 24 h rest–activity rhythm [ 29 , 30 , 31 ].…”

Circadian disturbances in Alzheimer's disease progression: a prospective observational cohort study of community-based older adults

“…Our longitudinal data showed that aging was associated with decreased amplitude, advanced acro phase, and increased intradaily variability of daily activity rhythms, findings that are consistent with those of crosssectional studies. 29,30 We also reported that interdaily stability pro gres sively decreased over time. By contrast, our baseline cross-sectional analysis suggested a positive correlation between interdaily stability and age; previous studies also reported either unchanged or higher interdaily stability in older adults.…”

Associations of circadian rest/activity rhythms with cognition in middle-aged and older adults: Demographic and genetic interactions

“…We computed standard parametric cosinor CRAR metrics, which are based on the assumption that CRARs reflect a cosine curve ( Ancoli-Israel et al, 2003 ), using the “cosinor” package 1 in R ( R Core Team, 2020 ). These included two measures of rhythm strength, namely amplitude (peak-to-trough difference) and mean of estimated cosinor curve (mesor; average activity level), and acrophase (timing of peak activity), a measure of circadian timing (i.e., “phase”) ( de Feijter et al, 2020 ).…”

“…We also calculated non-parametric circadian indices using the “ActCR” package 2 in R ( R Core Team, 2020 ), given that CRARs do not always manifest a cosinor (parametric) shape. Specifically, we computed: relative amplitude (RA; rhythm strength); interdaily stability (IS; consistency of rhythm across days); intradaily variability (IV; within-day rhythm fragmentation); midpoint of an individual’s total activity during the least active continuous 5 h (L5 time); and midpoint of an individual’s total activity during the most active continuous 10 h (M10 time) ( de Feijter et al, 2020 ).…”