Sleep Under 6 Hours Sharply Raises Heart Disease Risk, Study Shows

Sleep deprivation is threatening the health of modern populations. South Koreans rank among the lowest in average sleep duration among OECD member nations. According to research by the U.S. National Sleep Foundation, sleeping six hours or less consistently raises the risk of heart disease by up to 48%. Sleep stands as one of three pillars of health alongside exercise and diet.

Sleep experts recommend that all adults maintain a consistent bedtime each night, with the WHO advising 7 to 9 hours daily. Insufficient sleep leads to cognitive decline, cardiovascular disease, weakened immunity, and increased risk of obesity and diabetes. Improving sleep quality requires changes across daily habits including bedroom environment, light management, and dietary adjustments.

Light management comes first. Adequate exposure to natural sunlight or bright lighting during the day promotes melatonin secretion at night, improving sleep quality. However, blue light from smartphones and computers should be blocked starting two hours before bedtime, as it suppresses melatonin production and disrupts the body's circadian rhythm.

Dietary adjustments are also essential. Caffeine intake should stop at least eight hours before bedtime. Research shows late caffeine consumption shortens total sleep time by approximately 45 minutes. Alcohol also disrupts sound sleep. While it may initially induce drowsiness, alcohol damages sleep architecture and worsens snoring and sleep apnea. Reducing fluid intake one to two hours before bed can minimize nighttime awakenings.

Maintaining a consistent daily rhythm matters as well. Going to bed and waking at the same time every day, including weekends, stabilizes the body's internal clock. Naps should be limited to 30 minutes or less to avoid interfering with nighttime sleep. The bedroom should be kept cool and quiet. Experts recommend an ideal sleep temperature of approximately 18.3 degrees Celsius. Mattresses and bedding should be chosen to prevent body pain, and indoor air quality requires attention.

Relaxation activities before bed such as meditation, reading, or a warm bath serve as effective sleep signals. Those considering melatonin or magnesium supplements should consult a specialist first. Regular exercise benefits sleep improvement, but vigorous exercise immediately before bed can cause alertness. Researchers at Johns Hopkins University recommend completing exercise at least three hours before bedtime.

Chronic insomnia or sleep apnea that persists despite lifestyle changes warrants professional medical evaluation. Sound sleep results not from a single remedy but from harmonious management of light, diet, environment, and rhythm across daily life.