When it comes to sleep, not only how long you sleep but also when you sleep matters. If sleep timing remains out of sync with your circadian rhythm, sleep quality may decline.
The body's 'circadian rhythm' regulates not only sleep and wakefulness but also hormone secretion, metabolism and immune function. In particular, if bedtime continues to get later than midnight, it can affect this rhythm and the stages of sleep. However, midnight itself is not an absolute standard. What matters is avoiding a persistent mismatch between your circadian rhythm and your daily schedule.
◇Going to bed late may reduce deep sleep
Going to bed late may also affect the rhythm of hormones that regulate sleep and wakefulness. Melatonin rises at night and helps induce sleep, while cortisol increases around dawn and in the morning, preparing the body to wake up. If exposure to bright lights or smartphone screens late at night delays the time you fall asleep, these hormone cycles can become misaligned with your sleep schedule.
It may also affect deep sleep. Also known as slow-wave sleep, deep sleep plays an important role in physical recovery and memory processing and occurs mostly during the early part of sleep. Dr. Alex Dimitriu, a U.S. sleep medicine expert, told health publication EatingWell, "If you fall asleep late, slow-wave sleep, which primarily occurs early in the sleep period, may decrease." When deep sleep is insufficient, you may not feel refreshed even after getting enough sleep, and physical recovery and cognitive function may also be affected.
◇Persistent circadian misalignment may also be linked to chronic diseases
Maintaining a lifestyle in which sleep and wake times remain out of sync with the circadian rhythm over a long period is also associated with various health problems. A study published in the Journal of the American College of Cardiology, JACC, reported that persistent circadian misalignment was associated with cardiovascular disease, type 2 diabetes, obesity and depression. The risk of sleep disorders such as insomnia may also increase.
For healthy sleep, it is important to establish a regular daily rhythm rather than forcing yourself to fall asleep at a specific time. It is advisable to go to bed and wake up at similar times on weekdays and weekends, dim the lights one to two hours before bedtime and reduce exposure to smartphone or computer screens.
Getting plenty of sunlight in the morning can help. Morning natural light is an important signal for resetting the body clock. It is advisable to reduce caffeine intake after late afternoon and avoid relying on alcohol to fall asleep. Keeping the bedroom relatively cool may also help promote restful sleep.
The body's 'circadian rhythm' regulates not only sleep and wakefulness but also hormone secretion, metabolism and immune function. In particular, if bedtime continues to get later than midnight, it can affect this rhythm and the stages of sleep. However, midnight itself is not an absolute standard. What matters is avoiding a persistent mismatch between your circadian rhythm and your daily schedule.
◇Going to bed late may reduce deep sleep
Going to bed late may also affect the rhythm of hormones that regulate sleep and wakefulness. Melatonin rises at night and helps induce sleep, while cortisol increases around dawn and in the morning, preparing the body to wake up. If exposure to bright lights or smartphone screens late at night delays the time you fall asleep, these hormone cycles can become misaligned with your sleep schedule.
It may also affect deep sleep. Also known as slow-wave sleep, deep sleep plays an important role in physical recovery and memory processing and occurs mostly during the early part of sleep. Dr. Alex Dimitriu, a U.S. sleep medicine expert, told health publication EatingWell, "If you fall asleep late, slow-wave sleep, which primarily occurs early in the sleep period, may decrease." When deep sleep is insufficient, you may not feel refreshed even after getting enough sleep, and physical recovery and cognitive function may also be affected.
◇Persistent circadian misalignment may also be linked to chronic diseases
Maintaining a lifestyle in which sleep and wake times remain out of sync with the circadian rhythm over a long period is also associated with various health problems. A study published in the Journal of the American College of Cardiology, JACC, reported that persistent circadian misalignment was associated with cardiovascular disease, type 2 diabetes, obesity and depression. The risk of sleep disorders such as insomnia may also increase.
For healthy sleep, it is important to establish a regular daily rhythm rather than forcing yourself to fall asleep at a specific time. It is advisable to go to bed and wake up at similar times on weekdays and weekends, dim the lights one to two hours before bedtime and reduce exposure to smartphone or computer screens.
Getting plenty of sunlight in the morning can help. Morning natural light is an important signal for resetting the body clock. It is advisable to reduce caffeine intake after late afternoon and avoid relying on alcohol to fall asleep. Keeping the bedroom relatively cool may also help promote restful sleep.