Are busy city dwellers getting enough sleep every night? Let alone sleeping well! Besides restoringphysical strength, sleep also helps boostimmunity, organize memories, develop the brain, and manageemotions. Therefore, adequate sleep is crucial for the human body. A complete sleep cycle is about 90 minutes. However, how long should light sleep and deep sleep last each night to achieve good sleep quality? To establish good sleep habits, doctors advise paying attention to the following 5 things.
Sleep Cycle for Adults: Approximately 4 to 6 cycles, Non-Rapid Eye Movement (NREM) Sleep: 4 stages from light to deep sleep
Dr. Yuen Cheuk Wai, a specialist in emergency medicine at Hong Kong Sanatorium & Hospital, stated that a complete sleep cycle lasts approximately 90 minutes, and a normal adult needs about 4 to 6 sleep cycles per day, which means 6 to 9 hours of sleep. If calculated based on 8 hours of sleep, there would be about 5 cycles. Each cycle is divided into non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep is further divided into four stages: light sleep, deeper sleep, moderate sleep, and deep sleep.
Sleep Helps Organize Memories; Deep Sleep Accounts for 1-2 Hours
During the deep sleep stages (moderate sleep and deep sleep), the cerebral cortex is in a state of inactivity and complete rest, which greatly helps in relieving fatigue. However, deep sleep only accounts for one to two hours of the total sleep time; the remaining time is spent in light sleep (light sleep and deeper sleep) and REM sleep.
Dr. Yuen uses the analogy of making pottery: the process of deep sleep is for selecting which memories to retain, like forming a rough shape; REM sleep is for connecting these fragments into coherent memories and related events, like doing final touches. Most dreams occur during REM sleep. Dr. Yuen also points out that during the REM stage, the eyes move rapidly, while the body's muscles relax. This is an important protective mechanism that prevents involuntary body movements and potential injuries during sleep.
Only Staying in Light Sleep Leads to Poor Sleep Quality
In addition to getting enough sleep, the quality of sleep is also very important. It is crucial to maximize the duration of deep sleep, because if you continuously remain only in a light sleep state, you will still feel tired the next day, no matter how long you sleep.
Establish Good Sleep Habits: Pay Attention to 5 Things
To sleep well, Dr. Yuen suggests paying attention to the following 5 things to help establish good sleep habits:
- Maintain a regular schedule for work and rest.
- Establish a habit of regular exercise, ideally in the morning and under sunlight, as sunlight helps regulate the secretion of melatonin, which aids sleep.
- Avoid using electronic devices such as phones two hours before bedtime, as blue light can inhibit melatonin and affect sleep.
- Avoid consuming caffeinated or alcoholic beverages before bed.
- Pay special attention to issues like stress, medication, and sleep apnea, as these can all affect sleep quality.
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