The scientists , from Erasmus MC University Medical Center Rotterdam, and the Faculty of Health and Medical Sciences at the University of Surrey, United Kingdom, compared the number of white blood cells in 15 healthy young adult males who were subjected to normal sleep and severe sleep loss.
The greatest impact was on granulocytes - types of white blood cells - which lost their day-to-night time rhythmicity as numbers shot up, especially during nighttime.
Lead author, Katrin Ackermann, PhD, said:
"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.
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."
The authors explained that prior studies had found a link between lack of sleep and the development of certain diseases and conditions, such as high blood pressure (hypertension), diabetes and obesity. Other studies have demonstration that adequate sleep helps keep the immune system working properly, and that long-term sleep loss is a major risk factor for immune system problems.
The 15 young men were made to follow a strict routine of eight hours sleep every day for one whole week - their white blood cells were categorized and measured. Within 90 minutes of waking up, they were exposed to 15+ minutes of outdoor light. They were not allowed to consume anything with caffeine in it, they were told not to drink alcohol or take any medications. The aim here was to stabilize their circadian clocks and bring sleep deprivation down to a minimum before the intensive laboratory study.
The scientist compared the participants' white cell counts during their normal sleep/wake cycle week to the count during the second part of the experiment when the subjects were made to spend 29 hours without any sleep at all.
"The granulocytes reacted immediately to the physical stress of sleep loss and directly mirrored the body's stress response."
What are ganulocytes?A granulocyte is a type of white blood cell that is full of microscopic granules - tiny sacs that contain enzymes for digesting microorganisms.
Granulocytes form part of our innate immune system. Experts say they have a broad-based immune activity - they are nonspecific. Granulocytes are not like B-cells and T-cells which respond exclusively to specific antigens.
There are different types of granulocytes, including eosinophils, basophils and neutrophils; they get their names from their staining features in the lab.
Several problems associated with lack of sleep or sleep difficulties
Sleep deprivation and bad food choices - Investigators from the University of California demonstrated how sleep deprivation can undermine regions in the brain which are responsible for making food choices. They explained that their findings might explain why sleep deprivation is linked to a higher risk of becoming obese. (Link to article)
Lack of sleep and stroke risk - Normal weight adults who sleep less than six hours per night have a much greater risk of stroke symptoms during middle-to-older age than normal weight people who sleep more hours, researchers from the University of Alabama reported. (Link to article)
Lack of sleep is becoming a growing problem throughout the world
Lack of sleep and the appeal of junk food - people who have not had enough sleep and have "tired brains" are more likely to find junk foods appealing, researchers from Columbia University in New York, revealed. (Link to article)
Too many workers not sleeping enough - according to the CDC (Centers for Disease Control and Prevention), about one third of all workers in the USA are sleeping for less than six hours each day, instead of the recommended 7 to 9 hours. People especially at risk of not getting enough sleep included those working in health care, social assistance, transportation and warehousing sectors - many of them on shift-work. (Link to article)