a healthy person sleep for 8-9 hours a day. It’s essential as that relax the body and recharge us! We rest and sleep during night but our body keep working.
Our sleep is divided in 5 stages. stage 1 is Light sleep also known as nap, stage 2 is eye movement stops and brain waves become slower. During stage 3 brain waves become very slow which are called as delta waves. During stage 4 brain just create delta waves and rhythmic breathing starts. stage 3 and 4 are often known as deep sleep or delta sleep. stage 5 is REM (rapid eye movements). This whole cycle take 90 min and once REM complete again the stage 1 starts
our kidney’s main function is to filter toxins and harmful substance from blood stream and make urine. During sleep kidney keep filtering but the rate is slower.
During the anabolic sleeping stage our body secretes Human growth hormone. This hormone helps us in our growth and also maintain and repair muscles and the bone of your body.
During sleep, The salivary glands do not produce enough moisture to keep the mouth wet means low amount of saliva is produced. Mouth is active during the sleep that why few people grinding teeth.
Like just other organs, the immune system has also a circadian rhythm(A circadian rhythm is a around 24 hour cycle in the physiological processes of living beings that includes plants, animals, fungi and cyanobacteria). Number of T-cells in Blood increase and also the levels of cytokines are very high during sleep, while leukocytes and the anti-inflammatory cytokine IL-10 goes up during daytime.
During REM we feel the deep sleep. It last for 90-120 min, in adult its of 20 to 25% and in infants 80% is REM.
Due to Deep sleep skins metabolic rate is increased, This repairs the skin. Deep sleep is also known as the “beauty sleep” because skin tissue can not be repaired during day.