There are five stages of sleep. In stage one, your eyes are closed,
but you are easily waken up. This stage lasts for 5-10 minutes. Stage
two is a light sleep. The body temperature drops and heart rate slows
down. Stage three is a transitional sleep of light and deep. Stage four
is a deep sleep, which helps energy restoration, cell regeneration,
tissues repairment and strengthening the immune system. At stage
five-rapid eye movement (REM) sleep, dreaming occurs because of
increased brain activity. This stage helps learning, memory, and mood.
The five stages continue through the night for 4-5 times. Shortened
sleep hours interfere with the cycles, leading to impairment of physical
and emotional health.
Our genes decide how many hours of sleep we need at night. Some people need
4-5 hours, while others need 8-9 hours. After age 60, night time sleep
is shorter and lighter.
In humans, the hormone melatonin secreted by
brain pineal gland controls the circadian rhythm, a build in biological
clock that regulates the sleep-wake cycle by the light. Travel induced
time difference interferes with this rhythm, similar harm caused by
lights of mobile phone, TV, and electronic devices. Certain medical
conditions, i.e. pain, drugs, alcohol, stress, temperature, diet, and
physical activities all play roles in affecting our sleep quality. Sleep
deprivation leads to poor concentration, increased accidents, insulin
resistance, weight gain, Alzheimer’s disease, anxiety, depression, and
impaired immune function. If you are seeking for a natural miracle cure
to be happy, lean, healthy and resilience to bacteria and virus
infections, simply putting down your phone and get a good night sleep.
