Lack of sleep makes us feel weak, not excited, and more susceptible to disease. It happens because our body does not have time to restore energy and the immune system did not get time to improve.
A recent study published in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, explains how the immune system improves itself during sleep.
Researchers found that some subset of T cells decreased from the bloodstream during sleep where the risk of infection was low. T cells are a type of white blood cell and are the basis of the human immune system.
T cells exist in the bloodstream and are ready to attack viruses and other pathogens that attack the body. Even during a restful phase of rest, the body is able to release T cells, growth hormones, and restore epinephrine to the circulation to fight pathogens when needed.
In this research the researchers conducted an experiment to find out how sleep deprivation affects the immune system. There are 14 volunteers consisting of young men with an average age of 25 - participating in two 24-hour studies (from 8 pm to 8 pm).
In the experiment, volunteers were allowed to sleep between 11 pm and 7 am. While the rest, the men were asked not to sleep for 24 hours.
Blood samples were taken from each volunteer at varying intervals (90 minutes to three hours) over a 24-hour period. Among the sleeping groups, all measured T-cell subsets were reduced within three hours of falling asleep. However, T cell numbers remain high on subjects that are not allowed to sleep.
While research shows that T cells leave the bloodstream. Where they go is a mystery.
"This is an unsolved question about where cells are redistributed during sleep because we can not follow their migratory route in healthy humans ... There are some clues from previous studies that these cells accumulate in the lymph nodes when sleep, "the researchers wrote.
The rapid decline in circulating T-cells during sleep, says researcher Luciana Besedovsky, shows that even one sleepless night affects the immune system. "This ... maybe one of the reasons why sleep is so important to health."