Sarah has covered news topics for digital and print publications. She holds a degree in broadcast journalism from the University of Nevada.
A new study published in the journal Sleep found that newly hired early-morning shiftworkers may see an increased risk of cardiovascular disease as they transition to their earlier work schedules.
This comes on the heels of the U.S. Bureau of Labor Statistics August 6th employment update, citing more than 900,000 jobs added in July 2021. The report indicated that many of these jobs were gained in leisure, hospitality, and education fields — some roles in these fields require early shift start times.
By observing sleep patterns among a group of shiftwork bus drivers, the study found that when transitioning to their early-morning work schedules over a 90-day period, the drivers’ blood pressure was not decreasing enough while sleeping — a condition called “non-dipping,” in which blood pressure sees less than a 10% decrease from daytime blood pressure.
Of the participants studied over 90 days, 93% of the participants converted from a healthy dipping blood pressure to the non-dipping pattern — a figure that was more than 50% higher than the daywork group. In stark contrast, dayworkers’ non-dipping profile decreased to 0% after 90 days, a significant difference from those with disrupted sleep schedules.
The unhealthy changes in blood pressure that resulted in less of an overnight dip were also associated with sleep timing variability, which is an inconsistency in a person’s sleep and wake times. The association of the blood pressure change and sleep timing variation may indicate that the participant’s circadian rhythm, or internal body clock, is disrupted.
The changes in participants’ overnight blood pressure were due to higher exposure levels to early morning shiftwork. This study indicates that the risk for developing cardiovascular issues may increase the longer someone stays on shiftwork.
This study’s findings suggest that the transition into early-morning shiftwork followed by the changes in overnight blood pressure could contribute to the well-documented increased cardiovascular risk.
As cardiovascular disease is the leading cause of death in the United States this study offers insight into identifying early alterations in cardiovascular health among shiftworkers.