Too Much or Too Little Sleep Raises Death Risk

Change in sleep duration during midlife is associated in a U - shaped fashion with risk for death more than a decade later.
The major cause for 2.4 -fold increased death rate for people who usually slept 6 to 8 hours, but due to life circumstances were forced to limit their sleep to 5 hours or less a night, was cardiovacular .
In subjects who increased their sleep duration from 6-8 hours to 9 hours or more there was adjusted 2.1 fold increase in non-cardiovascular mortality.
Sleep deprivation is associated with hypertension, diabetes and weight gain, all of which increase cardiovascular risk.
But the mechanism for the relationship between long sleepand increased mortality is unclear.
Depression and cancer related fatigue are hypothesis worthy of investigation.