Objective: To examine a novel measurement of autonomic innervation, the early heart rate response to orthostasis, in relation to sleep duration and disturbance (actigraphy-based and self-reported) in healthy older adults.
Design: Cross-sectional analyses of a nationally representative prospective cohort study, the Irish Longitudinal Study on Ageing (TILDA).
Participants: Nine hundred sixty community-dwelling adults aged 50 and over (mean age 65.6 ± 8.1; 53% women).
Measurement: Orthostatic heart rate response was measured during an active stand test. Beat-to-beat heart rate was monitored over 3 minutes using noninvasive digital photoplethysmography. Mean values at each 10-second time point after standing were generated and differences from baseline at each time point were used for analysis. Actigraphy-based sleep measures were extracted from wrist-worn GENEactiv devices; self-reported sleep measures using interview questions.
Results: Linear mixed-effects regression analyses, with inclusion of a large number of confounders, show that self-reported sleep duration and actigraphy-based sleep duration and disturbance were associated with altered orthostatic heart rate response, particularly within the first 20 seconds poststanding. Self-reported short sleep (β = -0.06; 95% confidence interval [CI]: -0.11, -0.01) and long sleep (β = -0.15; 95% CI: -0.24, -0.05) and actigraphy-based short sleep (β = -0.08; 95% CI: -0.14, -0.01) were characterized by a smaller increase at 10 seconds (p < .01). Actigraphy-based short sleep (β = 0.15; 95% CI: 0.08, 0.22) and sleep disturbance (β = 0.04; 95% CI: 0.02, 0.06) were associated with a slower return toward baseline at 20 seconds (p < .001).
Conclusions: Our findings suggest sympathetic dysregulation, impaired vagal reactivation, and/or decreased baroreceptor sensitivity in the presence of shortened or disturbed sleep.
Keywords: Active stand; Autonomic function; Heart rate recovery; Sleep.
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