What percentage of total sleep time (TST) does N2 make up for adults?

The correct answer indicates that N2 sleep typically comprises 45 - 55% of total sleep time (TST) in adults. During a normal sleep cycle, N2 sleep is the largest proportion of the sleep stages and plays a crucial role in overall sleep architecture.

N2 is characterized by specific physiological changes, including a decrease in heart rate and a reduction in body temperature. It is also the stage where sleep spindles and K-complexes occur, which are important for memory consolidation and cognitive function. During this stage, the body begins to prepare for deeper sleep, making it essential for restorative processes.

Understanding the significance of the N2 stage helps in recognizing its role in sleep health and the overall sleep cycle, which includes not only deep sleep stages but also REM sleep, each contributing differently to overall well-being and restorative functions.