A typical sleep cycle lasts about 90 minutes and includes both non-REM (light and deep) and REM stages. In the first half of the night, deep sleep dominates, which is important for physical recovery. REM sleep becomes more prominent in the latter half of the night, especially in the early morning hours. The longer someone sleeps, the greater the proportion of REM sleep in the later cycles.
REM-sleep is important for learning, memory consolidation, creativity, and emotional regulation—crucial elements for peak-performance in knowledge work.
While both sleep phases are important for everyone, it appears that knowledge workers are at a biological disadvantage here. Since REM is “second-in-line,” individuals who cut their sleep short (e.g., less than 6 hours) sacrifice a disproportionate amount of REM sleep.
Physical workers may derive most of their immediate benefits from deep sleep, which occurs earlier in the night. If their total sleep is slightly reduced, they might still receive adequate deep sleep for muscle recovery and immune function.
Knowledge workers may experience more noticeable cognitive deficits from insufficient sleep compared to physical workers, as REM deprivation directly impairs focus, problem-solving, and creativity.
So, when looking at (ways to improve) our sleep, its perhaps wise to be a bit more specific on the type of sleep we require most.
