Shift workers have a higher risk of heart attack than people who work constant hours, according to a new study. The scientists compared the risk of cardiovascular disease for warehouse workers who work shifts and compared it to their natural biological clock.
It was revealed that for every hour that a person’s natural body clock is out of sync with a person’s work rotation, the risk of developing a heart health problem (such as a heart attack) increases by 31 percent. European researchers focused on “circadian misalignment,” the difference between a person’s “social clock” and a person’s “biological clock.”
When these two aspects of a person’s life don’t align, the person suffers from fatigue, also known as ‘ social jetlag ‘.
The average worker has a social jetlag of 2 hours
Circadian rhythms are responsible for each person’s daily cycle and determine whether someone is a very early riser or a night owl.
Dr. Gamboa Madeira, author of the study from the University of Lisbon, said: “ We all have an internal biological clock that ranges from the morning types, who feel alert and productive in the early morning and sleepy at night, to late types, for whom the opposite occurs, with most of the population in the middle. Circadian misalignment occurs when there is a mismatch between what your body wants (for example, falling asleep at 10pm) and what your social obligations impose on you (for example, working until midnight) . “
The team of researchers had the participation of 301 people who work as collectors in a store of a point of sale that is operational 24 hours a day. Warehouse staff rotate in three different shifts; early (6 am – 15pm), afternoons (15pm – 00am) and nights (21pm – 6am).
Lifestyle questionnaires and cholesterol and blood pressure measurements were taken for all study participants. Most people’s circadian rhythm and work hours were found to be offline within two hours, and 59 percent of workers had a social jet lag of two hours or less.
Shift work increases the risk of heart attack by 31%
However, for 33 percent of the staff it was 2 to 4 hours, and for 8 percent it was four hours or more. A higher level of social jetlag was significantly associated with a higher chance of being in the high cardiovascular risk group , the researchers found.
The odds of being classified as high cardiovascular risk increased by 31 percent for each additional hour of social jet lag, even after adjusting for sociodemographic, occupational, lifestyle and sleep characteristics and BMI.
Dr Madeira said: “ These results add to growing evidence that circadian misalignment may explain, at least in part, the association found between shift work and unhealthy outcomes. The findings suggest that staff with atypical work hours may need closer monitoring of heart health . “
” Longitudinal studies are needed to investigate whether late chronotypes are better suited to late-night shifts and earlier chronotypes to early morning hours, both psychologically and physiologically .”
