Table 1.

Relationship between sleep duration, determinants of cardiovascular risk, and cardiovascular events

	Short sleep duration (< 7 h)	Long sleep duration (> 9 h)
Calories intake	↑	↑
Energy expenditure	↓?	?
Obesity	↑↑	↑
Arterial hypertension	↑	↑ ?
Diabetes mellitus	↑	↑↑
Atrial fibrillation	↑ ?	↑ ?
Stroke	↑	↑↑
Heart failure	↑↑	↑
Myocardial infarction	↑	↑↑
Coronary events	↑↑	↑
All cause death	↑	↑
Cardiovascular death	↑	=

Upwards/downwards arrows indicate increased/decreased risk for the relative condition, while the equal sign indicates similar risk compared with intermediate sleep duration. The same number of arrows indicates no difference in risk between short and long sleep duration. Question marks indicate controversial evidence. See text for details