Sleep deprivation jolts the immune system into action in the same type of immediate response shown during exposure to physical stress, according to a new study.
Researchers in the Netherlands and United Kingdom compared the white blood cell counts of 15 healthy young men under normal and severely sleep-deprived conditions.
The greatest changes were seen in the white blood cells known as granulocytes, which showed a loss of day-night rhythmicity, along with increased numbers, particularly at night, the researchers report.
Previous studies have linked sleep deprivation with diseases such as obesity, diabetes and hypertension. Other studies have shown that sleep helps sustain the functioning of the immune system, and that chronic sleep loss is a risk factor for immune system impairment, the researchers note.
For this study, white blood cells were measured from 15 young men following a strict schedule of eight hours of sleep every day for a week. The men were exposed to at least 15 minutes of outdoor light within the first 90 minutes of waking and prohibited from using caffeine, alcohol or medication during the final three days.
All of this was designed to stabilize their circadian clocks and minimize sleep deprivation before the intensive laboratory study, the researchers explain.
After 29 hours of continual wakefulness, the researchers took blood samples from the young men to compare white blood cell counts with the counts found during the normal sleep/wake cycle.
“The granulocytes reacted immediately to the physical stress of sleep loss and directly mirrored the body’s stress response,” said Katrin Ackermann, Ph.D., a postdoctoral researcher at the Eramus MC University Medical Center Rotterdam in the Netherlands and the study’s lead author.
“Future research will reveal the molecular mechanisms behind this immediate stress response and elucidate its role in the development of diseases associated with chronic sleep loss,” she said.
“If confirmed with more data, this will have implications for clinical practice and for professions associated with long-term sleep loss, such as rotating shift work.”