Experts Explain the Science Behind Modern Insomnia
“Not only do I sleep late, but my deep sleep never exceeds an hour.”
As soon as Li Mo stepped out in the morning, she received a sleep alert from her smart wearable. The physical fatigue she felt seemed to confirm the sleep data — over the past two weeks, her deep sleep had averaged only one hour per night.
The Modern Paradox: More Night Mode, Less Rest
“I even turned on night mode on my phone, so why do I feel more awake the more I scroll?”
Like many others, Li Mo tried the trending “9 PM night mode” challenge, hoping to improve her sleep. Yet, after a few days, she felt even more alert before bed.
According to Dr. Dong Xiaosong, Chief Physician of Sleep Medicine at Peking University People’s Hospital, many believe that using “night mode” on phones can offset the negative impact of screens.
However, research shows that even in night mode, electronic devices still impair sleep quality.
In March 2025, China’s National Patriotic Health Campaign Committee issued its Core Information and Interpretation of Sleep Health, clearly stating that staying up late, excessive screen use, heavy dinners, smoking, drinking, consuming tea or coffee before sleep, and late-night workouts all disrupt healthy sleep patterns.
The Lifestyle Trap of Urban Youth
Li Mo’s daily routine reflects that of many urban young adults:
- Morning and afternoon: relying on iced Americanos for alertness
- Evening: one-hour gym session combining cardio and strength
- Bedtime: scrolling through short videos under bright blue light
Her body’s fatigue is intensified by a triple combination — caffeine, late exercise, and prolonged screen exposure — all of which suppress the brain’s ability to enter deep sleep.
A national sleep report revealed alarming figures:
- Coffee or strong tea before bed → 64.8% experience sleep disturbance
- Heavy dinners → 57.7%
- Exercise before bed → 53.7%
- Screen use before sleep → 51.5%
Experts recommend:
✅ Eating until 70% full at dinner
✅ Avoiding snacks and electronics 1 hour before bed
✅ Choosing light activities (like yoga or walking) in the evening
✅ Avoiding intense exercise within two hours of sleep

The Essence of Insomnia: Systemic Dysregulation
“The human body’s sleep control system works like a dual-gear mechanism,” explained Dr. Lin Shijun, Chief Physician at Shenzhen Longgang District People’s Hospital.
“One gear — the circadian clock — tells us when to sleep. The other — the sleep homeostasis system — controls how deeply we sleep.”
1. Circadian Rhythm: The Body’s Natural Clock
Melatonin secretion rises at night and drops during the day.
But with today’s digital lifestyles, constant blue light delays this rhythm.
Studies show that each extra hour of screen time before bed increases insomnia risk by 59% and cuts total sleep by 24 minutes.
2. Homeostasis: The Role of Adenosine
Adenosine accumulates the longer we stay awake — it’s what makes us sleepy.
However, caffeine blocks adenosine receptors, preventing the brain from feeling tired. Even one iced Americano can disturb this delicate balance.
3. Stress and Cortisol: The Hidden Agitator
“Chronic stress keeps cortisol levels high,” noted Dr. Dong.
“This creates a state of pseudo-wakefulness, where the body feels tired but the brain won’t rest.”
In chronic insomniacs, sympathetic nervous activity during sleep remains 38% higher than in normal sleepers, fragmenting deep sleep and worsening fatigue.
“The essence of insomnia lies in a malfunctioning internal system,”
— Dr. Dong Xiaosong
Why Deep Sleep Matters
Sleep has three main stages: light, deep, and REM.
Deep sleep is the body’s repair mode, vital for physical recovery and brain detoxification.
During this phase, cerebrospinal fluid circulation accelerates, flushing out waste from the brain.
“Healthy sleepers get about 20% deep sleep, while insomniacs often get less than 10%,” said Dr. Lin. “That’s why some people feel exhausted even after eight hours in bed.”
Quality Sleep Can Be Managed
“Achieving quality sleep requires active management,” emphasized Dr. Jiang Yinan, Deputy Chief Physician at Peking Union Medical College Hospital.
Smart Habits for Better Rest
- Limit screen time: charge phones away from the bed to reduce temptation.
- Control light exposure: keep bedroom lighting below 30 lux (about moonlight level).
- Eliminate light leaks: cover indicator LEDs with tape or wear an eye mask.
- Seek daylight: step outside during lunch to regulate melatonin production.
For Shift Workers
Tailored sleep strategies are key:
- Take a pre-shift nap (~3 hours before work)
- Nap briefly during breaks to maintain alertness
- After night shifts, wear sunglasses to block morning light and aid daytime sleep
- Create an “artificial night” with blackout curtains and quiet surroundings
When Self-Management Isn’t Enough
If lifestyle adjustments fail, Cognitive Behavioral Therapy for Insomnia (CBT-I) offers a powerful, non-drug solution.
CBT helps patients:
- Break the “can’t sleep → anxiety → worse sleep” cycle
- Rebuild healthy sleep cues through behavior and mindset training
- Use mindfulness breathing to calm the body
“It’s like recalibrating a misaligned clock,” said Dr. Lin.
“Through small, consistent changes, the brain can relearn how to sleep naturally.”
Medication: A Double-Edged Sword
While sleep medications can help short term, they target anxiety rather than sleep itself, noted Dr. Dong.
Potential side effects include dry mouth, next-day drowsiness, falls, and dependency with long-term use.
“Medication adjustments should always be guided by professionals,” Dr. Jiang warned. “Never self-medicate.”
Final Thought
Modern insomnia is not just about “sleeping less,” but about living out of sync with our biological systems.
From caffeine and screens to stress and schedules, the modern world keeps our brains awake even when our bodies are exhausted.
But with science-backed strategies and active lifestyle adjustments, better sleep is within reach — one mindful night at a time.

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