Study: Daytime meals protect heart health in night shift workers

Editor's Note

Eating during the day instead of at night may protect shift workers from harmful cardiovascular effects, according to an April 17 report in Medscape on new research from Mass General Brigham. Researchers found that the timing of meals—not just their content—directly influences cardiac and clotting function in adults exposed to simulated night shifts.

The controlled, in-patient study involved 19 healthy adults ages 22 to 30 were placed in a strictly controlled, in-patient setting with no access to light cues or timekeeping devices, Medscape reports. After an initial 32-hour wake period with hourly snacks, participants were randomized to eat either only during the daytime or only during the nighttime while undergoing simulated night work. For the nighttime eaters, the findings revealed the following:

• The percentage of consecutive heartbeat intervals of less than 50 ms (pNN50) dropped 25.7%
• The root mean square of successive heartbeat differences (RMSSD) dropped 14.3%
• Low/high cardiac frequency (LF/HF) ratio increased 5.5%
• Blood concentrations of prothombotic factor plasminogen activator inhibitor 1 (PAI-1) increased 23.9%
• Blood pressure drops ranged from 6% to 8%.

 “We hypothesized that maintaining the time of eating synchronized with the circadian system may alleviate the adverse effects of simulated night work on cardiovascular risk factors,” reads a quote from Frank A.J.L. Scheer, PhD, a professor of medicine and director of the Medical Chronobiology Program at Brigham and Women’s Hospital, Boston. “We were amazed that meal timing could mitigate adverse effects even though sleep was still mistimed.”

According to the article, the team plans further research to evaluate how these findings apply in real-world shift schedules.