Final answer:
Stage N3 sleep, or deep sleep, is defined by delta waves occurring more than 50 percent of the time, with these waves exhibiting low frequency and high amplitude. Delta waves in N3 sleep represent the deepest stage of NREM sleep, making it difficult to awaken an individual during this stage.
Step-by-step explanation:
Typically, stage N3 sleep is characterized by delta waves occurring more than 50 percent of the time. This stage of non-REM (NREM) sleep, also recognized as slow-wave sleep, exhibits low frequency, high amplitude delta waves. These waves are distinct in that they have the lowest frequency (less than 3 Hz) and highest amplitude when compared to other sleeping brain wave patterns. It's during this stage that an individual's heart rate and respiration slow significantly, and the likelihood of waking someone from sleep diminishes substantially.
As such, stage N3 represents the deepest stage of sleep, where the sleeping brain waves are dominated by these delta waves. The presence of delta waves thus serves as a hallmark for the depth and quality of sleep during this phase. It is worth to note, contrasting characteristics are observed during REM sleep. REM is marked by active brain patterns similar to those experienced in wakefulness and is often associated with dreaming and muscle paralysis.