March 12, 2016 08:22
Sleep disorders appear to increase as people age, and not only do people sleep less, but the quality of sleep also deteriorates.
Old people often do not feel refreshed no matter how many hours they sleep, and this leads to a general feeling of fatigue and inability to concentrate on work during the day, said Heo Kyoung, a sleep expert at Severance Hospital.
Last year, 279,876 people sought treatment for sleep disorders, compared to 213,887 in 2011. And 68 percent were in their 50s or over, according to the Health Insurance Review and Assessment Service.
People enter rapid eye movement or REM sleep after passing through three stages -- closing eyes, light sleep and deep sleep. And this cycle is repeated five to six times a night under normal sleeping conditions.
During REM sleep, the brain becomes alert and starts to dream.
But as people age, they tend to flounder in the first and second stages and never reach the REM stage. "This means they rarely have a sound or deep sleep, which can diminish brain functions and damage health. They experience poorer memory and ability to make quick decisions and have trouble with digestion, circulation and immunity functions." Heo said.
The main reason is probably a decrease in the secretion of melatonin. Also known as the sleep hormone, it is being secreted in increasing amounts around two hours before bed time.
A high level of melatonin secretion is maintained past midnight and into the early hours of the morning, only to decrease sharply when the sun rises. But people aged 51 to 65 secrete only half the amount of melatonin as those in their 20s and 30s, and over the age of 64 just a third, according to research.
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