The number of people suffering from sleep disorders is climbing steeply, from 110,000 in 2005 to 410,000 in 2014.
People in their 50s are especially prone, who according to the Health Insurance Review and Assessment Service account for 65 percent patients with sleep disorders.
Studies show that the quality of sleep deteriorates as people grow older because they experience a decrease in the secretion of melatonin that induces and maintains sleep. The biological clocks also changes, causing them to wake up earlier.
Waking up at irregular hours commonly causes sleep disorders, a study finds. It seems people need to wake up at regular time for their biological clock to move in sync.
"The biological clock is triggered by the light of day and shuts off when the sun goes down, but people see less sunlight during the day and are exposed to bright lights at night, which damages the biorhythm and leads to sleep disorders," says Lee Heon-jeong at Korea University Anam Hospital.
Under normal circumstances the body's hormonal routine should lead to the lowest blood pressure, heart rate and body temperatures levels at around 2 a.m., but irregular schedules impact this flow, leading to irritability and lethargy during the day.
Excessive use of white light, such as fluorescent lamps, is also a problem, according to experts. Fluorescent lamps emit a lot of light on the blue spectrum, which causes people to fall asleep later and wake up at night.
Smartphone screens also give off blue light, so they should be put away before heading to bed.
Doctors also advise dimming the lights at night and avoiding excessive physical labor so that the body temperature can gradually drop. They also advise against taking long naps during the day and bringing work and other study materials to bed.
Taking walks in sunlight during the day is recommended. If sleeplessness persists for more than three months, visit a doctor and perhaps ask about medication.