Importance of Sleep Blood Pressure

Blood pressure varies throughout the day and night and is maintained at different times by different control systems. 2. During the awake interval, the sympathetic nervous system is preeminent but during sleep the renin angiotensin system is the controller. 3. Sleep blood pressure is a more powerful predictor of non-haemorrhagic cerebro- and cardiovascular events in animals and humans, despite the sleep value being lower than the day value. 4. Drugs that act independently of the hormonal or neural systems, such as diuretics and calcium channel blockers, have similar effects during sleep and awake intervals. Beta-blockers have little effect during sleep when the activity of the sympathetic is low while drugs that interfere with the action of the renin angiotensin system have a greater blood pressure lowering effect during sleep. 5. One aim of therapy should be to ensure that blood pressure is low during sleep and drugs should be used in doses that lower blood pressure throughout the 24 h period.