Skipping sleep 'hardens arteries'
People who scrimp on sleep are more likely to develop hardening of their arteries, a precursor to heart disease, research suggests.
Calcified arteries were found in nearly a third of people who slept fewer than five hours a night.
This dropped to around one in 10 for those who slept an extra hour, the Journal of the American Medical Association study of 495 adults found.
Experts said getting enough sleep was important for good heart health.
The risk was lowest for those who regularly had more than seven hours sleep each night.
Firstly, there may be some factor not yet identified that can both reduce sleep duration and increase calcification.
Or it might be down to blood pressure - high blood pressure increases the likelihood of calcification and blood pressure goes down during sleep.
Alternatively, stress or a stress hormone like cortisol, which has been tied to decreased sleep and increased calcification, may play a role.
Ellen Mason, of the British Heart Foundations, said: "It is not yet clear quite how sleep affects our heart disease risk, but this study adds to previous research suggesting that getting enough sleep may help to keep our heart and circulations healthy."
"Sleep is essential for our body's ability to repair itself and with the party season in full flow, it is important to try and get enough rest."
"Drinking alcohol late at night and getting up early can mean we're not getting enough quantity, or quality, of sleep."