upgrade

🥸intro to psychology review

Delta Sleep

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Delta sleep, also known as slow-wave sleep (SWS), is a stage of non-rapid eye movement (NREM) sleep characterized by the presence of high-amplitude, low-frequency brain waves. This stage is considered the deepest and most restorative phase of the sleep cycle.

5 Must Know Facts For Your Next Test

  1. Delta sleep is the deepest and most restorative stage of the sleep cycle, characterized by slow, high-amplitude brain waves.
  2. During delta sleep, the body's metabolic rate and blood pressure decrease, while blood flow to the muscles increases.
  3. This stage of sleep is believed to be important for physical restoration, growth, and immune function.
  4. Delta sleep is more prevalent in the first half of the night and decreases as the sleep cycle progresses.
  5. Factors such as age, sleep deprivation, and certain medical conditions can affect the amount of delta sleep an individual experiences.

Review Questions

  • Explain the characteristics of delta sleep and how it differs from other stages of the sleep cycle.
    • Delta sleep, also known as slow-wave sleep (SWS), is the deepest and most restorative stage of the sleep cycle. It is characterized by high-amplitude, low-frequency brain waves, which indicate a state of deep relaxation and reduced brain activity. During delta sleep, the body's metabolic rate and blood pressure decrease, while blood flow to the muscles increases. This stage of sleep is believed to be important for physical restoration, growth, and immune function. Delta sleep is more prevalent in the first half of the night and decreases as the sleep cycle progresses, unlike the lighter stages of NREM sleep (N1 and N2) and REM sleep.
  • Describe the physiological changes that occur during delta sleep and their significance.
    • During delta sleep, the body undergoes several physiological changes that are important for overall health and well-being. The metabolic rate and blood pressure decrease, allowing the body to conserve energy and focus on restorative processes. Additionally, blood flow to the muscles increases, facilitating muscle repair and growth. These changes are believed to be crucial for physical restoration, as well as supporting the immune system and other vital bodily functions. The deep relaxation and reduced brain activity associated with delta sleep are also thought to be important for cognitive processing, memory consolidation, and overall mental well-being.
  • Analyze the factors that can influence the amount of delta sleep an individual experiences and the potential consequences of disruptions to this stage of the sleep cycle.
    • Several factors can influence the amount of delta sleep an individual experiences, including age, sleep deprivation, and certain medical conditions. As people age, the amount of delta sleep typically decreases, which can contribute to the sleep disturbances often seen in older adults. Sleep deprivation can also disrupt the normal sleep cycle, leading to a reduction in delta sleep and potentially impacting physical and cognitive function. Additionally, medical conditions such as sleep apnea, chronic pain, and neurological disorders can interfere with the quality and quantity of delta sleep. Disruptions to delta sleep can have significant consequences, including impaired physical restoration, weakened immune function, and cognitive impairments, such as difficulty with memory and decision-making. Understanding the factors that influence delta sleep and the importance of this stage of the sleep cycle is crucial for maintaining overall health and well-being.