Editor's Note: Dr. Sun Wei is a chief physician and head of the Sleep Medicine Department at Peking University Sixth Hospital. In this guide, Dr. Sun explores the "three pillars" of quality sleep – rhythm, drive, and relaxation – while offering a professional look at the latest medical treatments. He also provides a much-needed reality check on sleep trackers, shifting the focus from digital data to how we actually feel and function during the day.

We spend roughly one-third of our lives asleep. Far from being mere "downtime," healthy sleep is essential for replenishing physical energy, clearing metabolic waste from the brain, consolidating memory, and supporting immune function. Yet the 2025 China Sleep Health Survey Report presents a sobering picture: 48.5 percent of adults in China report sleep-related problems, and more than 300 million people are affected by sleep disorders.

The most common clinical complaints include difficulty falling asleep, difficulty staying asleep, and waking too early, all of which can impair daytime functioning. When these symptoms occur at least three times per week and persist for three months or longer, they meet the diagnostic criteria for chronic insomnia disorder. This condition is associated with cognitive impairment, reduced immune function, and a significantly increased risk of comorbid psychiatric and medical conditions.

Treatment for chronic insomnia generally falls into two broad categories: pharmacological treatment and behavioral and psychological interventions. Domestic and international clinical guidelines consistently recommend Cognitive Behavioral Therapy for Insomnia (CBT-I) as the first-line treatment. Before turning to medication, many patients can benefit substantially from behavioral adjustments and sleep-focused self-regulation.

Healthy sleep depends on three key factors: circadian rhythm, sleep drive and relaxation.

1. Circadian rhythm: Your internal clock

Circadian rhythm refers to the body's natural sleep–wake cycle. To keep it stable, consistency is essential. Try to go to bed and wake up at the same time every day. For people with insomnia, a fixed sleep window – for example, 10:30 p.m. to 5:30 a.m. – may be recommended. Maintain this schedule regardless of the quality of your sleep the night before.

2. Sleep drive: Your need for sleep

Sleep drive, also known as sleep pressure, builds up the longer you stay awake. The stronger the sleep drive, the easier it is to fall asleep and maintain sleep continuity. To preserve this natural process, avoid taking naps or trying to "catch up" on sleep during the day. Moderate exercise, such as brisk walking, jogging, or swimming, can also strengthen sleep drive. It is best, however, to finish exercise at least two hours before bedtime.

3. Relaxation: Preparing body and mind for sleep

Physical and mental tension is a major barrier to sleep. Relaxation techniques can help reduce anxiety and prepare the body for rest. One useful technique is progressive muscle relaxation: lie comfortably in bed, gently close your eyes to take several deep breaths, then bring your awareness to the top of your head, visualizing the tension melting away. Following this method, systematically relax each part of your body in sequence: the face, neck, shoulders, arms, chest, abdomen, back, and finally, your legs. This can help reduce physical tension and make it easier to fall asleep. You can also try the 4-7-8 breathing technique: inhale through your nose for 4 seconds, hold your breath for 7 seconds, and exhale slowly through your mouth for 8 seconds. Repeating this cycle three to four times can help calm the nervous system.

In terms of medication, although benzodiazepine receptor agonists (BZRAs) are commonly prescribed, they may carry risks such as next-day residual effects, cognitive impairment, and dependence. A newer class of medications, dual orexin receptor antagonists (DORAs), works by blocking orexin-mediated wake-promoting signals in the brain, thereby helping restore a more natural sleep–wake balance. These drugs can be effective in reducing nocturnal awakenings and generally have a lower risk of dependence. Other options, such as melatonin receptor agonists or certain low-dose antidepressants, may also be considered depending on the patient's condition. Any sleep medication should be used under the guidance of a qualified physician.

Many people now use smartwatches or smart rings to track the quality of their sleep. But how reliable are these measurements?

According to clinical standards, deep sleep (N3 sleep) typically accounts for about 13 to 23 percent of total sleep time in healthy adults. For someone sleeping 6 to 7 hours per night, about 50 minutes of deep sleep can be entirely normal. It is also a normal physiological phenomenon for deep sleep to decline with age.

Wearable devices can be useful for estimating total sleep duration and identifying broad sleep patterns, but they are less accurate than polysomnography (PSG) in distinguishing sleep stages such as deep sleep and rapid eye movement (REM) sleep. These devices are best used as general reference tools rather than precise diagnostic instruments.

Ultimately, the best measure of sleep quality is your daytime function. Rather than becoming overly focused on device-generated data, ask yourself a simple question: "How do I feel during the day?" If you are able to work, think clearly, and maintain steady energy throughout the day, your sleep is likely serving its essential purpose.

(Cover image designed by Sha Yunjin)