Extreme fatigue is the product of shift work across a 24-hour period and it is a side-effect of working in service designed to provide 24-hour cover, such as medical services. It is well established that shift work, either through being awake when the body should naturally be asleep or through sleep deprivation, affects cognitive responses and alterations to the body clock can trigger physiological effects; however information about the heart specifically is less well-known.
To examine the effect on the heart further, research has been undertaken by the Department of Diagnostic and Interventional Radiology at the University of Bonn in Bonn, Germany. The research, as The Daily Telegraph reports, was led by Dr. Daniel Kuetting and reported to the recent meeting of the Radiological Society of North America.
The research involved assessing 20 people (19 men, one woman) with an average age of 32 years. The participants agreed to undergo a cardiovascular magnetic resonance imaging examination. This was run at the start of the study and then following a 24-hour shift, during which the subjects slept for around three hours.
In addition, blood and urine samples were taken, together with measurements for heart rate and blood pressure. The results revealed that, at the end of the 24-hour shift, the participants saw increases in peak systolic strain and rises in blood pressure and heart rate. There were also increases in thyroid stimulating hormone and the stress-response hormone cortisol. These measures are signs, if sustained for a long-period, of a risk of cardiac arrest and other heart problems.
Speaking with Bioscience Technology, Dr. Kuetting explains further about the effects of sleep deprivation on cardiac function. “For the first time, we have shown that short-term sleep deprivation in the context of 24-hour shifts can lead to a significant increase in cardiac contractility, blood pressure and heart rate.”
The study was an initial look and Dr. Kuetting plans further research, especially to measure variations over the longer-term. Such research is seen as important in response to societal changes requiring people to work more varied hours. Additional variables to be considered include workload and shift duration.
In related news an earlier study by the University of Warwick found that people who slept for less than six hours each night were 12 per cent more likely to die prematurely compared with those who slept the recommended six to eight hours a night.
