Not getting enough sleep on a regular basis can cause a build-up of plaque in the arteries, which causes them to stiffen and close up.
The standard theory of heart disease states that fatty foods cause the arteries to 'fur up' and narrow, but it's more to do with insomnia, say researchers at the Massachusetts General Hospital.
Sleep helps to regulate the production of inflammatory cells and healthy blood vessels, and so it would it would follow that the lack of sleep has the reverse effect.
The researchers demonstrated the effect when they tested the theory on a group of laboratory mice. Although the cholesterol levels of the sleep-deprived mice remained the same, they produced larger arterial plaques and double the number of inflammatory cells that are known to contribute to atherosclerosis.
Hypocretin, a hormone that helps regulate sleep, also helps control production of white blood cells, the researchers discovered.