# Daily personal light exposure patterns and sleep in emergency department healthcare workers (administrative supplement to R01 HL146911)

> **NIH NIH R01** · COLUMBIA UNIVERSITY HEALTH SCIENCES · 2022 · $456,588

## Abstract

PROJECT SUMMARY / ABSTRACT
Light is the strongest biological signal influencing the human circadian system, and by extension, sleep.
Exposure to light of sufficiently high levels during the daytime, combined with dim light/darkness during the
evening and night, is necessary to maintain robust and appropriately timed circadian rhythms in physiology
and neuroendocrine secretion, and to promote good sleep of sufficient duration. Conversely, reduced light
exposure levels throughout the daytime and increased light exposure occurring at the “wrong time” (e.g., the
biological night) can disturb sleep by causing circadian misalignment, disrupting melatonin secretion,
increasing neurocognitive arousal, delaying sleep initiation, and worsening sleep quality. The light
environment and its impact on sleep is important to consider because sleep influences nearly all aspects of
physical and mental health and disease, as well as daily function and performance. Thus, personal light
exposure represents an important malleable contextual factor that influences a critical health behavior (sleep).
In an ongoing prospective 3-year observational cohort study (R01HL146911, MPI: Chang/Shechter;
“IMPROVE Study”), we are evaluating the impact of environmental stressors and disturbed sleep on
cardiovascular and psychological risk in emergency department (ED) healthcare workers (HCWs). An
overarching goal of the IMPROVE Study is to evaluate the short- and long-term contribution of objectively-
estimated short sleep duration and poor quality sleep to acute and progressive changes in blood pressure and
psychological risk (e.g., burnout). In the current administrative supplement, we will leverage the infrastructure
of the ongoing IMPROVE Study to add on an objective assessment of personal light exposure patterns via a
small wearable mini-spectrophotometer (light pin) in a subset of participants who are enrolled in the parent
IMPROVE study. This subset of participants will wear the light pin during one of their scheduled annual 2-
week data bursts in which sleep is continuously tracked under free-living conditions. The aim of the
administrative supplement is to determine the relationship between light exposure patterns and our main
behavioral predictor of cardiovascular and psychological risk—sleep. Examining how personal light exposure
patterns relate to sleep will provide information on the mechanistic role of this factor in influencing sleep. This
work can inform the development of novel behavioral interventions focusing on personal light exposure
patterns to improve sleep and downstream health-related outcomes.

## Key facts

- **NIH application ID:** 10666252
- **Project number:** 3R01HL146911-03S1
- **Recipient organization:** COLUMBIA UNIVERSITY HEALTH SCIENCES
- **Principal Investigator:** Bernard P. Chang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $456,588
- **Award type:** 3
- **Project period:** 2022-09-07 → 2024-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10666252

## Citation

> US National Institutes of Health, RePORTER application 10666252, Daily personal light exposure patterns and sleep in emergency department healthcare workers (administrative supplement to R01 HL146911) (3R01HL146911-03S1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10666252. Licensed CC0.

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