Day eat shields night shift workers from heart risks

Day eat shields night shift workers from heart risks

A new study shows that limiting meals to times of day may help preserve cardiovascular function and reduce disease risk in night shift workers, highlighting the power of mealtimes in mitigating circadian disruption.

A recently published study inNature communicationExamines how daytime eating may maintain cardiovascular health in night shift workers.

Changed eating habits during shift work

About 15% of workers residing in developed countries perform night shift work, which increases the risk of cardiovascular disease (CVD). Circadian misalignment that occurs due to disruptions between the central circadian pacemaker and normal sleep/wake cycles likely contributes to dysfunctional cardiometabolic health in shift workers.

Circadian organization is fundamental to normal health and longevity, while circadian disruption is involved in the etiology of heart disease. “

The relationship between shift work and cardiovascular health is multifactorial, with several studies suggesting that mealtime may contribute to increased CVD risk in shift workers. To elucidate the role of eating in this risk, researchers in the current study compared the effects of eating during the day and night only during the day in a cohort of study participants exposed to simulated night work.

About the study

The researchers in the current study conducted a single-blind study with seven women and 12 men. To simulate night work, the forced desynchrony protocol was used, exposing study participants to a total of four 28-hour days.

In each 28-hour cycle, all meals were consumed in Night Time Meal Control Control (NMC) during the day and night, which is common among shift workers.

The remaining study participants were placed in the Daytime Meal Intervention (DMI) group, which included a modified 28-hour FD protocol. All meals in the DMI group were consumed during the day.

Cardiac vagal regulation was assessed using the percentage of consecutive normal cardiac interbeat intervals greater than 50 milliseconds (PNN50), root square of successive differences (RMMSD), which is a marker of heart rate variability and low/high heart rate (LF/HF). Levels of circulating plasminogen activator inhibitor-1 (PAI-1), a prothrombotic factor involved in circadian rhythms, were also measured alongside heart rate and blood cortisol levels.

Cardiovascular measurements were assessed during constant routine (CR) protocols, minimizing the potential behavioral and environmental effects on physiological parameters.

Eating every day preserves heart function

After exposure to simulated night work, PNN50 and RMSSD values ​​in the NMC group decreased by 25.7% and 14.3%, respectively, compared to baseline levels. These changes were not observed in the DMI group.

Simulated night work also resulted in a significant increase in LF/HF ratio values ​​of 5.5%, while no change was observed in the DMI group. PAI-1 levels increased by 23.9% in the NMC group after simulated disadvantage, while the DMI study participants showed no significant change in PAI-1 levels.

No significant changes in cortisol levels or heart rate were observed in the NMC and DMI groups. However, blood pressure levels were reduced by 6-8% in the DMI group after exposure to simulated night work.

Implications

By limiting eating to only times of day, study results show that the timing of eating, rather than the simulated night shift, has more of an impact on cardiovascular health than night work alone. In particular, eating during both nighttime and daytime periods, rather than alone, resulted in reduced cardiac vagal modulation, which has been consistently reported in previous clinical studies.

Timing of daily meals avoids the adverse effects of simulated work on cardiovascular function in humans. “

Night shift workers often eat their meals during the night hours, skipping other meals during the day and snacking frequently. Study results confirm the importance of meal timing in mitigating the risk of cardiovascular disease in night shift workers and suggest that mealtime behavioral interventions are available to improve health outcomes in this population.

Nevertheless, future studies with larger sample sizes and real-world displacement work conditions, including rotating or irregular work routines, are needed to validate and extend these results.

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