A study in The Netherlands observed the relationship between sleep and heart disease among 20,432 men and women. Researchers found that short sleep contributes to cardiovascular disease and coronary heart disease.

The research was conducted over a 12-year period. None of the Dutch participants had any heart disease when first examined. But during years of follow-ups, more than 2,600 cases of cardiovascular disease and coronary heart disease developed. The study was able to link these heart diseases to particular sleep habits.

Short sleepers had a 15 percent higher chance of cardiovascular disease. Short sleepers with sub-par sleep quality had an even higher chance, 63 percent. The chance for developing coronary heart disease was 23 percent higher in short sleepers. And for short sleepers with a poor quality of sleep, the chance of developing coronary heart disease was 79 percent higher.

Short sleep was defined as six hours of sleep or less. Long sleep was considered sleep for nine hours or more. There were no links seen between long sleep and cardiovascular disease or coronary heart disease.

The study was published in the November issue of the journal SLEEP.