Journal Article

Daytime eating during simulated night work mitigates changes in cardiovascular risk factors: secondary analyses of a randomized controlled trial

Hu, Kun, Gao, Lei, Vujovic, Nina, Scheer, Frank A.J.L., Chellappa, Sarah L., Qian, Jingyi, Li, Peng

2025

Overview

Effective countermeasures against the adverse cardiovascular effects of circadian misalignment, such as effects experienced due to night work or jet lag, remain to be established in humans. Here, we aim to test whether eating only during daytime can mitigate such adverse effects vs. eating during the night and day (typical for night shift workers) under simulated night work (secondary analysis of NCT02291952). This single-blind, parallel-arm trial randomized 20 healthy participants (non-shift workers) to simulated night work with meals consumed during night and day (Nighttime Meal Control Group) or only during daytime (Daytime Meal Intervention Group). The primary outcomes were pNN50 (percentage consecutive heartbeat intervals >50 ms), RMSSD (root mean square of successive heartbeat differences), and LF/HF (low/high cardiac frequency). The secondary outcome was blood concentrations of prothrombotic factor plasminogen activator inhibitor-1 (PAI-1). These measures were assessed under Constant Routine conditions, before (baseline) and after (postmisalignment) simulated night work. The meal timing intervention significantly modified the impact of simulated night work on cardiac vagal modulation and PAI-1 ( p FDR = 0.001). In the Control Group, the postmisalignment Constant Routine showed a decrease in p NN50 by 25.7% ( p FDR = 0.008) and RMMSD by 14.3% ( p FDR = 0.02), and an increase in LF/HF by 5.5% ( p FDR = 0.04) and PAI-1 by 23.9% ( p FDR = 0.04), vs. the baseline Constant Routine. In the Intervention Group, there were no significant changes in these outcomes. For exploratory outcomes, the intervention significantly modified the impact of simulated night work on blood pressure ( P < 0.05), with no significant change in the Control Group, and a significant reduction by 6-8% ( P < 0.01) in the Intervention Group; without significant effects for heart rate or cortisol. These findings indicate that daytime eating, despite mistimed sleep, may mitigate changes in cardiovascular risk factors and offer translational evidence for developing a behavioral strategy to help minimize the adverse changes in cardiovascular risk factors in individuals exposed to circadian misalignment, such as shift workers. Circadian misalignment, which typically occurs in shift work, associates with cardiovascular diseases. Here the authors report that eating only in the daytime during simulated night work mitigates adverse changes in cardiovascular risk factors (including autonomic cardiac control, prothrombotic factor, and blood pressure) in a secondary analysis of a randomized controlled trial.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/378/1385/2640 / 692/308/575 / 692/699/75 / 9/25 / Adult / Autonomic nervous system / Blood pressure / Cardiovascular diseases / Cardiovascular Diseases - etiology / Cardiovascular Diseases - physiopathology / Cardiovascular Diseases - prevention & control / Circadian Rhythm - physiology / Circadian rhythms / Clinical trials / Daytime / Eating / Eating - physiology / Female / Health risks / Heart Disease Risk Factors / Heart rate / Heart Rate - physiology / Humanities and Social Sciences / Humans / Intervention / Jet lag / Male / Meals / Middle Aged / Misalignment / multidisciplinary / Night shifts / Nighttime / Plasminogen Activator Inhibitor 1 - blood / Plasminogen activator inhibitors / Risk Factors / Science / Science (multidisciplinary) / Secondary analysis / Shift work / Shift Work Schedule - adverse effects / Single-Blind Method / Vagus nerve / Work Schedule Tolerance - physiology / Young Adult