What conclusion can be drawn from high REM sleep without sufficient NREM sleep?

High REM sleep without sufficient NREM sleep generally suggests that the individual may not be achieving restorative sleep cycles effectively. During a typical sleep cycle, NREM sleep, particularly stages 3 and 4 (or slow-wave sleep), is crucial for physical restoration, immune function, and overall health. If a person is experiencing a predominance of REM sleep without adequate NREM stages, it indicates a disruption in the expected sleep architecture, which can prevent complete physical and mental restoration that typically occurs during NREM stages.

Restorative sleep is characterized by a balance of REM and NREM sleep, with the latter being essential for recovery and rejuvenation. Therefore, an imbalance where NREM sleep is insufficient can lead to symptoms such as daytime fatigue, impairments in cognitive function, and a lack of energy, indicating that the sleep is not truly restorative.

While the other options suggest positive aspects of sleep or conditions like insomnia, they do not accurately reflect the implications of a high amount of REM sleep in the absence of restorative NREM sleep.