# Influence of Nocturnal Light Exposure on the Impairment of Glucose Tolerance Induced by Chronic Sleep Restriction

> **NIH NIH R01** · BRIGHAM AND WOMEN'S HOSPITAL · 2021 · $778,208

## Abstract

ABSTRACT
Two-thirds of Americans report regularly obtaining an insufficient amount of sleep. Chronic sleep deficiency is
associated with a multitude of negative health consequences, including obesity, cardiovascular disease,
diabetes, and metabolic syndrome. Habitually sleeping less than the recommended seven hours per night has
been linked to increased all-cause mortality and increased risk of mortality associated with metabolic syndrome,
and prospective epidemiological studies have found an association between short sleep duration and increased
risk of type 2 diabetes. Laboratory studies have shown that sleep restriction to 4-6 hours per night for durations
varying from one to 14 days reduces glucose tolerance in otherwise healthy adults. It is now recognized that
sleep restriction decreases insulin sensitivity. Multiple additional causative pathways have been explored,
including reduced brain glucose utilization, increased sympathetic nervous activity, elevated evening cortisol
levels, etc. However, sleep restriction in both free-ranging humans and prior experimental studies is
accompanied by longer exposure to Artificial Light At Night (ALAN), an endocrine disruptor which can disrupt
circadian rhythmicity. It has recently been recognized that circadian disruption itself can impair glucose
metabolism. We hypothesize that endocrine and circadian disruption caused by extended duration ALAN may
contribute to the adverse metabolic effects induced by chronic sleep restriction. To test this hypothesis, we will
systematically evaluate glucose metabolism in healthy adults in controlled laboratory conditions (light,
temperature, diet and activity patterns) using a crossover design consisting of a 7-day baseline, 7-day sleep
restriction (to 5h per night) with (Light:Dark 19:5) or without (Light:Dark 14:10) ALAN, 9-day washout, and another
7-day sleep restriction with or without ALAN. Glucose metabolism (using an intravenous glucose tolerance test
and a Standardized Mixed Meal Response) and circadian rhythms (using 24-h profiles of plasma melatonin and
cortisol) will be assessed before and after each sleep restriction segment. Understanding whether extended
duration ALAN is a primary upstream exposure that contributes to the sleep-restriction-induced impairment of
glucose metabolism and consequent increase in diabetes risk is important given the widespread prevalence of
sleep deficiency. By clarifying a potential modifiable mechanism by which sleep restriction adversely affects
whole-body energy homeostasis, our findings will lay the groundwork for the development of novel treatments
and countermeasures to mitigate the adverse metabolic effects of chronic sleep restriction.

## Key facts

- **NIH application ID:** 10297979
- **Project number:** 1R01DK127254-01A1
- **Recipient organization:** BRIGHAM AND WOMEN'S HOSPITAL
- **Principal Investigator:** Charles A Czeisler
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $778,208
- **Award type:** 1
- **Project period:** 2021-07-29 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10297979

## Citation

> US National Institutes of Health, RePORTER application 10297979, Influence of Nocturnal Light Exposure on the Impairment of Glucose Tolerance Induced by Chronic Sleep Restriction (1R01DK127254-01A1). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/10297979. Licensed CC0.

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