Getting enough quality sleep is important for the immunity and health in general.
The interesting thing is that sleep can affect the blood pressure drastically. 1741 men and women participated in a recent study to evaluate how insomnia and poor sleep affected blood pressure (Alexandros N., et al. 2009).
The participants were divided into three categories. One group, 50% of the participants got 6 hours or more of sleep per night. Another group got approximately 5-6 hours of sleep and the third group slept for 5 hours or less per night.
As you probably have guessed the ones with insomnia and less than five hours sleep duration had the highest risk for hypertension (high blood pressure) and then came the participants with insomnia who slept between 5-6 hours. The risk for hypertension was also significantly higher, but of lesser magnitude, in poor sleepers with short sleep duration.Alexandros N. et al. Insomnia with Objective Short Sleep Duration is Associated with a High Risk for Hypertension. Sleep 2009;32(4):491-497.