What happens in each sleep stage?

Modified on Thu, 13 Apr, 2023 at 3:23 PM

Light sleep: Light sleep is a stage of sleep when you are most easily awakened.  Light sleep generally takes up roughly 50-60% of a daily sleep cycle and is often classed as being the leftover time not spent in REM or deep sleep. Having too much light sleep relative to the required deep and REM sleep may result in waking up feeling unrefreshed.


Deep sleep: Deep sleep is a stage of your sleep identified by a specific pattern of brain waves, also referred to as slow-wave sleep.  While all stages of sleep are necessary for good health, deep sleep offers specific physical and mental benefits. This includes the building and repairing of muscle, bone, and tissue, as well as the optimal functioning of the immune- and metabolic systems. Deep sleep is also important for optimal cognitive functioning and memory. When it comes to deep sleep, more is better, however, 13-23% of deep sleep daily is regarded as sufficient for healthy adults. 

  • More than 13% : Excellent

  • 8-13% : Fair

  • Less than 8% : Poor


Your deep sleep debt is an indication of how much deep sleep your body needs in a 72-hour period. Not getting enough good quality sleep can contribute to irritability and daytime fatigue. Other effects of insufficient sleep include feeling hungry all the time, not being satisfied by food, and having poor focus. Over time, sleep deprivation may impact your mental wellness. 


Give your body the opportunity to restore its rhythm by getting adequate sleep (7-9 hours) while ensuring your environment is as conducive to rest as possible. 

REM sleep: Rapid eye movement (REM) sleep is the stage of your sleep with the highest brain activity and is often associated with vivid dreaming. REM sleep is important for memory consolidation and daytime functioning. It is also good for creativity, problem-solving, and plays an important role when learning new skills. 21-30% REM sleep daily is regarded as optimal for healthy adults. Your REM sleep debt indicates how much REM sleep you need to get today to catch up on deficient REM sleep of the previous nights, measured over a 72-hour period. 


REM Onset Latency output refers to the duration between you falling asleep and the start of your first REM sleep cycle. A REM Onset Latency of 60-120 minutes is considered normal: 

  • More than 60 minutes : Excellent

  • 30-60 minutes : Fair

  • Less than 30 minutes : Poor


Awakening: LifeQ refers to awakenings as periods of wakefulness less than 5 minutes in duration each. Brief awakenings are normal and expected during sleep. You may not remember these events.



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