# Methods for Assessment of Sleep and Circadian Rhythms in Cardiovascular Research

## TL;DR

This review discusses methods for measuring sleep and circadian rhythms, highlighting their importance in cardiovascular health and the need for both subjective and objective assessments.

## Contribution

The paper provides a comprehensive overview of current and emerging methods for assessing sleep and circadian rhythms in cardiovascular research.

## Key findings

- Sleep health is multidimensional and includes factors like regularity, satisfaction, and timing.
- Subjective and objective sleep measurements may reflect different aspects of sleep health.
- Novel, less burdensome methods are being developed to assess circadian rhythms.

## Abstract

Sleep is recognized in Life’s Essential 8™ as an important behavioral factor for improving and maintaining cardiovascular health. While sleep duration is currently the focus in Life’s Essential 8™, sleep health is multidimensional and encompasses regularity, satisfaction, next-day alertness, timing, efficiency, and duration. In addition to sleep, circadian factors have also been implicated in cardiovascular health. For example, shift work, which results in significant circadian misalignment, is associated with poor cardiovascular health. This review will describe methods for measuring, analyzing, and interpreting sleep and circadian rhythms in humans. Subjective and objective measurements of sleep are not always concordant and may reflect distinct constructs. Therefore, both subjective and objective sleep measurements are discussed. Assessment of the circadian system in humans typically relies on the measurement of circadian biomarkers (i.e., melatonin, core body temperature, and/or cortisol) during rigorous and burdensome research protocols. However, novel approaches are being developed to estimate circadian parameters with lower cost and participant burden. This review aims to inform cardiovascular scientists and clinicians of common practices in the assessment of sleep and circadian rhythms.