# The impact of overnight nutrition support on sleep and circadian rhythm disruption in the ICU

> **NIH NIH K99** · MASSACHUSETTS GENERAL HOSPITAL · 2021 · $166,462

## Abstract

Intensive care unit (ICU) environments do not support sleep or preserve circadian rhythms of postoperative
critically ill patients. Among the contributing factors is the common practice of administering nutrition support
through feeding tubes overnight. Sleep and circadian rhythms, our 24-hour internal clock, are essential to
human well-being. Acute disturbances are associated with inflammation and cardiometabolic derangements, two
important factors known to impair patient recovery and contribute to longer stays at cardiac surgical ICUs. Thus,
the overall objective of the study is to examine a novel dimension of clinical nutrition by determining whether
enhancing sleep quality and preserving robust circadian rhythms through daytime instead of overnight feeds will
attenuate inflammation and improve cardiometabolic profiles of postoperative cardiac ICU patients on nutrition
support. My findings from a free-living adults clinical trial indicate differences in blood pressure and impaired
glucose tolerance in response to a glucose challenge administered during the biological evening relative to the
morning. To be a researcher at the intersection of nutrition and chronobiology, or chrono-nutrition,
leading a “bench-to-bedside” translational precision nutrition research program, which directly tests
discoveries from healthy subjects into patient populations, a logical next step is to evaluate clinical translation of
my findings in an ICU. I hypothesize that overnight nutrition support results in fragmented sleep and blunted
circadian rhythms and thus represent a modifiable mechanism exacerbating inflammation and cardiometabolic
derangements in postoperative cardiac patients. This hypothesis will be tested in three specific aims: Aim 1
[K99] proposes a randomized-controlled, crossover trial of 60 ICU patients on enteral feeds to test the hypothesis
that daytime compared to overnight enteral nutrition is associated with less fragmented sleep and more robust
24hr circadian rhythms. Sleep and circadian rhythms will be assessed objectively using non-invasive and state-
of-the-art technologies including polysomnography, actigraphy and body temperature. Aim 2 [R00] will test the
hypothesis that daytime compared to overnight nutrition is associated with gene expression signatures of robust
circadian rhythms and reduced inflammation via noninvasive blood monocyte transcriptomics. This will be tested
in the clinical trial from Aim 1 (n=60; Aim 2A) and in my ongoing complementary cross-over trial of free-living
adults for generalizability (n=335 completed; Aim 2B). Aim 3 [R00] will test the hypothesis in the clinical trial
from Aim 1 that daytime compared to overnight enteral nutrition is associated with reduced inflammation and
improved cardiometabolic profiles, including blood pressure and glucose. My interdisciplinary research plan,
proposed training in ICU clinical trials implementation and medical chronobiology, along with a unique clinical
research environme...

## Key facts

- **NIH application ID:** 10215183
- **Project number:** 1K99HL153795-01A1
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Hassan S. Dashti
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $166,462
- **Award type:** 1
- **Project period:** 2021-04-16 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10215183

## Citation

> US National Institutes of Health, RePORTER application 10215183, The impact of overnight nutrition support on sleep and circadian rhythm disruption in the ICU (1K99HL153795-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10215183. Licensed CC0.

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