Sleep Time Blood Pressure and Cardiovascular Risk Reduction
Blood pressure levels during sleep are useful indicator of cardiovascular health.
Ambulatory blood pressure monitoring is a novel way for doctors to measure patients’ blood pressure throughout the course of an entire day, typically for a period of 24 hours. These monitors use a small digital blood pressure machine connected to a cuff around the upper arm that patients can wear while going about their normal day and night. There are a number of benefits of utilizing ambulatory blood pressure monitoring, such as avoiding the “white coat effect” — when patients’ blood pressure increases in healthcare settings. It also helps track how a patient’s blood pressure rises and falls throughout the day, giving doctors a more complete picture of their health. With the creation of ambulatory blood pressure monitoring, researchers have also been able to learn more about the importance of sleep-time blood pressure: blood pressure levels at night when sleeping versus levels when awake during the day.
A recent study published in the Journal of the American College of Cardiology reports that decreasing blood pressure when asleep may actually be more effective in reducing cardiovascular risk than simply reducing blood pressure when awake. In this study, researchers followed 3,344 subjects over about 5.5 years. Each year participants were given ambulatory blood pressure monitors that measured their blood pressure over the course of 48 hours. Results showed that for every 5 mmHg decrease in asleep systolic blood pressure, risk for cardiovascular disease or events decreased by 17%.
Not only do these findings support increased use of ambulatory blood pressure monitoring, they encourage the use of sleep-time blood pressure as an extremely useful marker of cardiovascular risk. Why? Blood pressure drops greatly during sleep, and is largely unaffected by outside factors when uninterrupted. Awake blood pressure, however, can vary greatly throughout the day and may not always be an accurate marker of a patient’s blood pressure, depending on when it is measured. By measuring asleep blood pressure, doctors have more reliable figures to use in evaluating a person’s health.
Questions for You to Consider
- How can I reduce my sleep-time blood pressure?
- Patients can decrease their sleep-time blood pressure the same way that they reduce their awake blood pressure: maintaining a healthy diet and weight, exercising regularly and avoiding smoking. There are also a number of medications that doctors can prescribe to help lower blood pressure, which can be useful, particularly in combination with positive lifestyle changes.