Recordings of brain wave activity revealed that the participants in the S groups spent the most time in the stage of sleep characterized by sleep spindles. This observation indicates that they were in which stage of sleep?
This observation indicates that they were in the stage 2 NREM of sleep.
Explanation:
The non-rapid eye movement sleep (NREM sleep) is characterized by high voltage waves at slow speed displayed on the electroencephalographic monitor (EEG).
The sleepers who experience this stage of sleep are deemed to get healthy sleep.
Both the heart rate and breathing during this stage of sleep in slow and normal.
The blood pressure level does not exhibit fluctuation and the sleeper is also still.