slow-wave sleep

noun

: the phase of non-REM sleep marked by the deepest sleep and the highest levels of delta wave activity with brain and muscle activity significantly reduced, loss of response to external stimuli greatest, and with heart rate and respiration at lowest levels

Note: Sleep time spent in slow-wave sleep is of longer duration during infancy and childhood.

Deep, or slow-wave sleep, when the body secretes human growth hormone, is critical for development and physical repair.

—Melinda Beck

Members of a second group were awakened every time they entered slow-wave sleep, a stage when dreams tend not to occur.

—Sandra Blakeslee

—abbreviation SWS

Examples of slow-wave sleep in a Sentence

Recent Examples on the Web

The work directly tied the oscillations of slow-wave sleep to memory—and pointed to a way of using slow-wave sleep to improve memory. —Ingrid Wickelgren, Scientific American, 20 Feb. 2024

These stages are followed by deep sleep, also known as slow-wave sleep, where the body undergoes significant restorative processes. —Joanna Fong-Isariyawongse, The Conversation, 31 Jan. 2024

Given that alcohol is a sedative, achieving sleep right away is often shorter for drinkers, and some fall into deep sleep rather quickly, which can create an imbalance between slow-wave sleep and REM sleep, resulting in less of the latter and more of the former. —Dominique Fluker, Essence, 2 Jan. 2024

At sea, the birds did experience some slow-wave sleep while apparently resting at the water’s surface. —Brian Handwerk, Smithsonian Magazine, 30 Nov. 2023

Factors that Influence Deep Sleep According to Matthew Pase, PhD, lead author of the study and associate professor at the Turner Institute at Monash University in Australia, declines in slow-wave sleep over time were greatest among people in their 70s. —Nick Blackmer, Verywell Health, 7 Nov. 2023

During a typical night, a person goes through four stages of sleep: stage 1 (initially falling asleep), stage 2 (light sleep), stage 3 (deep sleep, or slow-wave sleep), and rapid eye movement (REM) sleep, when the brain is particularly active. —Nick Blackmer, Verywell Health, 7 Nov. 2023

Deep sleep, also known as slow-wave sleep, is the deepest stage of sleep. —Nick Blackmer, Verywell Health, 7 Nov. 2023

People with severe sleep apnea who spent less time in deep, also known as slow-wave sleep, had more damage to the white matter of the brain than people who had more slow-wave sleep, according to the study. —Sandee Lamotte, CNN, 10 May 2023

Word History

First Known Use

1964, in the meaning defined above

Medical Definition

slow-wave sleep

noun

: the phase of non-REM sleep marked by the deepest sleep and the highest levels of delta wave activity with brain and muscle activity significantly reduced, loss of response to external stimuli greatest, and with heart rate and respiration at lowest levels

Note: Sleep time spent in slow-wave sleep is of longer duration during infancy and childhood.

Members of a second group were awakened every time they entered slow-wave sleep a stage when dreams tend not to occur.

—Sandra Blakeslee

—abbreviation SWS