Which brainwave state is typically present during the light phases of sleep?

During the light phases of sleep, specifically during the early stages of non-REM (NREM) sleep, theta waves are the predominant brainwave pattern. Theta waves are characterized by a frequency of 4 to 8 Hz and are associated with light sleep and relaxation, transitioning between wakefulness and deeper stages of sleep.

While alpha waves are also present during a relaxed state and precede sleep (often observed while an individual is awake but calm and resting), it is during the initial stages of sleep, particularly Stage 1 NREM sleep, that theta waves become prominent. As sleep deepens, brain activity shifts further into different wave patterns, including delta waves which are associated with deeper sleep.

In summary, theta waves best represent the brain activity observed during the light phases of sleep, aligning well with the physiological changes that occur during these early sleep stages.