New Study May Explain How Poor Sleep Clogs Arteries

Jose Aguilar

Bad sleep can clog your arteries and lead to other conditions like obesity, and no one really knows why. However, Science Magazine reports on a new Harvard Medical School study that may have just found out the missing link.

Fatty deposits can build up on artery walls, eventually rupturing them. White blood cells flock to the damaged blood vessels and spawn cells that contribute to the formation of plaque.

Immunologist Filip Swirski hypothesizes that poor sleep triggers white blood cell production, contributing to the plaque formation on those who are already at risk of heart disease.

To test this, he picked mice genetically prone to arterial plaques and disrupted their sleep by nudging their cage with a metal bar every two minutes for 12 hours a day. He did this for 12 weeks. This is to emulate the feeling of constantly waking up to a barking dog or to a crying baby in the middle of the night.

Compared to the control group of lucky mice that were allowed to sleep their regular hours, the sleep-deprived mice showed larger plaques in their arteries and a higher white blood cell count.

Studying the mice further (who, after 12 weeks of sleep deprivation, probably welcomed the sweet release of death) revealed that they had reduced levels of orexin, which regulates arousal, wakefulness, and appetite. Cross-referencing his findings with mice that are unable to produce orexin revealed that those mice also have a higher white blood cell count. This suggests that orexin, which is depleted by lack of sleep, also regulates white cell production -- at least in mice.

It's important to reiterate that so far, this hypothesis has only been proven in mice. There's no guarantee that humans have a similar system.

Testing it on humans will be a bit tricky as few people would be willing to volunteer to that type of experiment. If it does result that we have a similar system, however, neuroscientist Asya Rolls notes that it would have implications for our entire being, not just our arteries.

"[Once you start] to affect immunity, you are opening many other conditions that might be explained."