Shiftworkers risk heart disease
Shiftworkers, truck drivers and those who work irregular hours may be at increased risk of heart disease, an Italian study has found.
The American Heart Association reports in its journal Circulation, that researchers from the University of Milan have found the body does not compensate for the additional stresses and strains that nightshift imposes.
The study involved tracking the heart activity of steelworkers using ECG recordings across three different shifts: day, afternoon and night. The results offer an interesting insight into the way the body regulates itself, regardless of what is going on in the outside world.
ECG measurements were taken constantly over 24 hours, two days after each worker started a new shift. The researchers found that nerve activity that accelerates the heart was lower during the overnight shift compared to morning or afternoon working periods. This lower night activity, they said, means a worker may be less able to perform mental and physical tasks.
Researchers also found that levels of the hormone cortisol, which stimulates heart rate, digestion and breathing during the day, did not adjust to the night shift worker's new routine.
Previous studies found that shiftworkers had a higher incidence of heart disease than their co-workers, and this new research may explain why.
"This resistance of the body's internal 'clock' to change with varied work schedules indicates that people don't adapt as easily as we think to shift work, and could explain why shift workers are at higher risk," said Dr Raffaello Furlan, a professor of medicine at the University of Milan.
