Deep sleep, characterized by slow brain waves, heart rate, and respiration, is essential for memory formation and immune function. Evidence suggests deep sleep influences cardiovascular health, too. A recent study found that deep sleep enhances left ventricular function – how well the heart’s left ventricle pumps blood throughout the body with each heartbeat.
Researchers recruited 18 healthy adult males to participate in a sleep study. They measured their brain and heart activity, blood pressure, and carotid pulse-wave velocity (a measure of arterial stiffness). When the participants reached deep sleep, the researchers exposed them to short bursts of pink noise (white noise with the high frequencies filtered out).
They found that the pink noise enhanced the participants' slow-wave brain activity. Interestingly, it also improved their left ventricular function, as indicated by enhanced pumping and filling capacities. Exposure to pink noise increased systolic blood pressure slightly but did not influence arterial stiffness.
Sleep occurs in distinct stages, the most prominent of which is non-rapid eye movement (NREM) sleep – typically referred to as “deep sleep” or “slow-wave sleep.” It comprises approximately 75 to 80 percent of a person’s total sleep time. During NREM sleep, the body produces growth hormone, which plays a role in metabolism.
The findings from this small study suggest that pink noise promotes deep sleep, driving improvements in cardiovascular function. Other evidence suggests that deep sleep provides a homeostatic recalibration of blood pressure, further supporting cardiovascular health. Learn more in this clip featuring Dr. Matthew Walker.
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