It should be noted that humans display two general types of brain wave activity namely the Beta Wave and the Alpha Wave. The former is most often detected when we are wide awake, while the latter is present during the state of sleep.
The Theta Waves activity continues through the second stageof sleep. The two defining characteristics observed during Stage 2 is the appearance of K complexes and sleep spindles. There is a sudden increase in both the frequency and amplitude of brain wave activity in Stage 2. It is also during this stage that core body temperature and heart rate begin to gradually decrease. It may not even feel like you are already sleeping during the first two stages of sleep as brain wave activity still hasn’t shifted completely from Beta to Alpha Wave activity.
Stage 3 and Stage 4
Stages 3 and 4 of sleep are characterized by the appearance of Delta Waves. It is during the third stage that we are most likely to transition from light sleep to deep sleep. Delta Waves are known to be highest in amplitude and lowest infrequency. There are no distinguishing qualities that clearly separate the third and fourth stage of sleep, except that there are more than 50% of Delta Waves during Stage 4 sleep. We are most likely to feel disoriented and sleepy when awakened during these sleep stages. In addition, sleep disorders namely sleep walking, sleep talking, and bed wetting mostly occur during Stage 3 or Stage 4 ofsleep.
Stage 5 or REM Sleep
As the name implies, REM sleep is characterized by rapid eye movement and temporary paralysis of skeletal muscles. The brain wave patterns during Stage 5 are a combination of desynchornous Alpha and Beta Waves. It is during the fifth stage of sleep when we are most likely dreaming. Paradoxical sleep is a term associated with Stage 5 of sleep as brain activity and other bodily functions increase while body movement is in a more relaxed and restful state.