Working the graveyard shift could be hazardous to your health.
Dutch researchers found that employees who regularly perform shift work have elevated levels of cortisol – a stress hormone that could contribute to the development of cardiovascular disease.
The study is based on a comparison of 33 people assigned to rotating shifts and 89 individuals who worked only days. The researchers obtained average cortisol levels by analyzing samples of hair – which provide a remarkably accurate record of various substances that passed through the blood stream.
The findings, published in the Journal of Clinical Endocrinology & Metabolism, revealed that shift workers had significantly higher levels of cortisol than their counterparts with day-time jobs.
Cortisol is known as the stress hormone because it enables the body to react quickly when faced with a challenging situation. "One big effect of cortisol is that it increases the glucose levels to make sure you have enough energy for a fight-or-flight response," explained the lead researcher, Laura Manenschijn of Erasmus Medical Centre in Rotterdam.
However, if glucose remains high indefinitely – as seen in the shift workers – it can lead to diabetes, abdominal obesity and high blood pressure, all risk factors for heart attacks and strokes, Dr. Manenschijn added.
She said it may be possible to safeguard the health of shift workers by treating them with cortisol-lowering medications. But she stressed that doctors won't be considering the drug option until a lot more research has been done.