Heart Disease Risks Increased by Working Night Shifts — Check out the Reason Here!

A new study published in the Proceedings of the National Academy of Sciences on Monday could shed light on why there is an increased risk of heart disease among those people working in shift schedules.

Researchers from the Brigham and Women's Hospital (BWH) found that the negative effect in the health of shift workers, such as cardiovascular and inflammatory consequences in healthy adults is a result of the short-term circadian misalignment. This occurs when there is a rapid 12-hour inversion of the sleep/wake and fasting/feeding cycle that is common among shift workers.

In a press release posted on EurekAlert, the Brigham and Women's Hospital (BWH) researchers said that those who experience circadian misalignment or the disruption of the "body clock" frequently are at risk for hypertension, inflammation, and cardiovascular disease.

"We were able to determine, under highly controlled laboratory conditions, the independent impact of circadian misalignment on cardiovascular disease risk factors—blood pressure and inflammatory markers," said senior author Dr. Frank Scheer, a neuroscientist in the Division of Sleep and Circadian Disorders at BWH, in a statement.

"Our findings provide evidence for circadian misalignment as an underlying mechanism to explain why shift work is a risk factor for elevated blood pressure, hypertension, inflammation and cardiovascular disease."

The research team monitored a group of volunteers in terms of how their bodies reacted when they rapidly inverted their normal sleep/wake and fasting/feeding cycles by a full 12 hours. The volunteers were asked to stay in a BWH sleep laboratory for more than two weeks, reported Medical Daily.

They took part in two separate 8-day stays. In one of their stays, they were allowed to sleep in their normal sleeping patterns. On the other stay, they slept normally for the first three nights, but were then asked to sleep at 11 a.m. up to 7 p.m. This reversal in the sleep schedule resembles that of the shift workers'.

The findings show that when the volunteers experience circadian misalignment, there was a higher blood pressure (both systolic and diastolic) for 24 hours afterward, less autonomic nervous system activity, and increased signs of inflammation.

One of the limitations of the study, however, is that it involves healthy adults subjected to short-term circadian misalignment. And, according to lead author Dr. Christopher J. Morris, associate physiologist in the Division of Sleep and Circadian Disorders at BWH, the effect of circadian misalignments could be different on those with hypertension, and on those who have shifting work schedules.

"Further research is needed to investigate countermeasures for the adverse cardiovascular effects of circadian misalignment, such as the timing of eating and exercise," he said.