Bad Sleep Turns Your Immune System Against You
DNA is altered, dumping too many white blood cells into the body in what appears to be a lasting problem.
Lack of sleep is known to lower your immune defenses and lead to higher risk for all sorts of diseases in the near term and over time. New research offers some insight as to why: Sleep that’s too short or fragmented during the night actually alters the DNA inside stem cells that create your body’s white blood cells, key to the immune system.
The result is somewhat counterintuitive: The stem cells kick out too many white blood cells, flooding the body and causing an overreaction of the immune system that can trigger inflammation, which in turn can lead to heart disease and other inflammatory disorders. Catch-up sleep, already deemed of dubious value, does not seem to rectify the problem.
“The stem cells have been imprinted, or genetically altered, under the influence of sleep restriction,” said study team member Filip Swirski, PhD, director of cardiovascular research at the Icahn School of Medicine at Mount Sinai in New York City.
Put another way, the creative force behind the immune system is fundamentally altered, and the system loses some of its protective effects, worsening infections.
For the study, 14 healthy adults had their blood tested before a six-week period of sleep restriction, in which they slept 90 minutes less than their normal 7–1/2 or eight hours. Blood was drawn again after those six weeks, revealing higher levels of both the stem cells and the white blood cells.
A similar test in mice involved waking them several times at night, creating fragmented sleep rather than just reduced duration. A similar increase in stem cells and white blood cells was measured, as well as the altered cell DNA.
“It shows that in humans and mice, disrupted sleep has a profound influence on the programming of immune cells and rate of their production, causing them to lose their protective effects and actually make infections worse — and these changes are long-lasting,” Swirski said in a statement.
The findings are published today in the Journal of Experimental Medicine.