What Is The Difference Between Light Sleep & Deep Sleep

Sonali Kapoor

, Health A2Z



Sleep is very important for the human body. If you are not taking a good sleep, you cannot concentrate on your work, because your body is not able to recover properly. It also affects your bone health, mental stress and makes you more lethargic. Mood swings, unsatisfaction, and disappointment are also some of the reciprocals of an improper sleep routine. Nowadays, most of the people are suffering from sleep insomnia, thus, today, we are going to discuss the difference between light sleep and deep sleep and how to enhance your sleep routine.


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What are the Stages of Sleep?


There are 5 stages of sleep :



Stage 1


In stage 1, the drift from being awake to being asleep. This is a light, NREM sleep which doesn’t last very long. You start to relax and dream but may also twitch as you transition into stage 2.


Stage 2


In stage 2 of the sleep cycle is still a light sleep, but you are drifting into a steadier sleep. Your breathing and heartbeat slow down, and your muscles relax. Your body temperature decreases, and your brain waves are less active.


Stages 3 and 4


In stage 3, you enter deep sleep, and stage 4 is the deepest sleep stage. In deep sleep, your breathing, heartbeat, body temperature, and brain waves reach their lowest levels. Your muscles are extremely relaxed, and you are most difficult to rouse.


Stage 4


It is known as the healing stage when tissue growth and repair take place, important hormones are released to do their jobs, and cellular energy is restored.


REM (Rapid Eye Movement) Sleep


The first REM cycle of the night begins about 90 minutes after you fall asleep and recurs every 90 minutes. The eyes move around quickly behind the eyelids and the brainwaves look similar to those of someone who is awake. Your breathing, heart rate, and blood pressure rise to near-waking levels.


REM sleep often referred to as stage 5, is when you are most likely to dream. Your arms and legs become temporarily paralyzed during this stage to prevent you from physically acting out your dreams.


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What is the Difference Between Light Sleep and Deep Sleep?



The sleep is divided into 2 categories of light sleep and deep sleep:


Light Sleep



Light sleep is a non-REM stage, and it’s easiest to wake up during this stage. It happens in stages 1-2. The beginning stage of light sleep is a transition phase and only makes up about 3% of our total time asleep; most light sleep happens in the second stage. The second stage of light sleep consists of over half of our time asleep each night. During this stage, the dreams are not as intense as they are during REM sleep.


Usually, as people age, they spend more time each night in light sleep. There is no specific amount of time needed in this phase since it’s not as refreshing as deep sleep. It is a necessary sleep stage for proper brain functioning.


Deep Sleep


Deep sleep is “ a time of nearly complete disengagement from the environment.” Deep sleep is also known as delta sleep, slow-wave sleep or N3. It is a restorative sleep state where dreams do not occur, and still relatively little is known about it.


During this stage, heart rate and breathing slow and your muscles relax to the point where you barely move. Deep sleep is necessary for your body to repair itself and recharge for the next day. Your organs detoxicate, your kidneys clean your blood, and your body replaces cells, heals wounds, and builds muscle tissues as well.


Most of the time deep sleep happens in the first sleep cycle. If anyone who is awoken during deep sleep, he or she will usually feel disoriented for sometime after waking up. It can be very difficult to wake a person during deep sleep.


What is the Normal Sleep Pattern?


Usually, a person would begin a sleep cycle every 90-120 minutes resulting in four to five cycles per sleep time, or hours spent asleep. Some people do not go straight from deep sleep to REM sleep, however. For most, Stage 2 sleep comprises approximately 40-60% of total sleep time.


What is a Good Sleep Quality Percentage?


Asleep efficiency of 85 percent or higher is considered to be normal, while a sleep efficiency anywhere above 90 percent is considered to be very good. Asleep efficiency of lower than 85 percent is considered poor and is a sign that an individual needs to get more efficient sleep.




In this blog, we have discussed what is the difference between light sleep and Deep sleep and stages of sleep, sleep pattern, difference and more importantly the sleep quality percentage. If you are facing any sleep problem then the best way to manage this is to consult a good doctor.


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