slow-wave sleep

noun

ˈslō-ˈwāv- 

: 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 bad news is heat exposure has been shown to increase wakefulness and decrease slow-wave sleep (the most restorative sleep stage) and rapid eye movement (REM) sleep, which is important for emotional processing. —Samson McDougall, Health, 9 Aug. 2024

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, 1 Mar. 2024

In contrast, there was no effect when the sounds were played during slow-wave sleep. —Ingrid Wickelgren, Scientific American, 1 Mar. 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

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