The Shadow of Staying Up Late: Latest Research on Bedtime Procrastination and Negative Traits

1. Background: What is "Bedtime Procrastination"?

In Japan, "Bedtime Procrastination," where individuals delay going to bed by getting absorbed in late-night video streaming or social media, is becoming a social issue. This differs from intentional staying up late, as it involves actions like watching additional content or replying to emails despite being aware that it's time to sleep. A study by a team from the University of Utah suggests that this behavior is also related to "personality."

The Night Owl Situation in Japan

According to a survey on communication usage trends by the Ministry of Internal Affairs and Communications, the average smartphone usage among people in their 20s on weekdays is 4.7 hours. The proportion of usage before bedtime reaches about 30%, further compressing Japan's already lowest-class sleep duration among OECD countries (average 6.5 hours). In a survey on the Japanese language by the Agency for Cultural Affairs, 54% of young people responded that they "cannot stop staying up late."

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2. Research Overview: University of Utah Team's Research Method

The study was conducted with 390 participants aged 18 to 30 (average age 24) enrolled at a university in Utah, USA. Participants engaged in the following:

1. Chronotype Questionnaire—Determining morning/evening tendencies

2. Big Five Scale—Measuring neuroticism, extraversion, openness, agreeableness, and conscientiousness

3. 14-Day Sleep Diary—Recording bedtime, wake-up time, reasons, and mood from the previous night

4. Bedtime Procrastination Index—Rating "reasons for still being awake" on a 5-point scale

The data was analyzed using a combination of regression analysis and hierarchical clustering to calculate the correlation between personality traits and behavior. To ensure the reproducibility of the experiment, the research protocol is published on an open science platform.

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3. Revealed Correlations with the Big Five Personality Traits

3-1. Neuroticism

This trait showed the highest correlation, with the night owl group exhibiting a marked tendency to experience heightened anxiety, anger, or sadness before bed and excessive worry about the next day's events.

3-2. Decrease in Extraversion and Openness

Participants with low extraversion tended to avoid social stimuli and escape into digital content, while those with low openness lacked the willingness to adopt new sleep habits.

3-3. Decrease in Agreeableness and Conscientiousness

Lower agreeableness was associated with not aligning with the bedtime of family or housemates, and lower conscientiousness led to an increased likelihood of not adhering to the next morning's schedule, making it easier for the daily rhythm to become disrupted.

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4. Psychological and Behavioral Effects of Sleep Deprivation

Delaying bedtime by 1 hour increases subjective sleepiness by an average of 17% and decreases sustained attention by 11% (estimated by the University of Utah). This leads to

• decreased academic and work performance

• emotional regulation disorders (increased outbursts of anger, heightened depressive moods)

• inhibition of healthy behaviors (skipping breakfast, lack of exercise)

creating a vicious cycle. A study by the University of Tokyo's psychiatry department also reported that the risk of depression in groups sleeping less than 6 hours is 1.9 times higher than in groups sleeping 7 hours or more.

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5. The Reality and Challenges of Staying Up Late in Japan

5-1. Establishment of the "Smartphone Night Owl Culture"

In a 2025 survey by NTT Docomo Mobile Society Research Institute, 55% of teenagers and 47% of people in their 20s reported "watching videos while lying in bed." Viewing times, especially from 0:00 to 1:00, are increasing.

5-2. Impact of Long Working Hours and Late-Night Overtime

According to the Ministry of Health, Labour and Welfare's "Labour Safety and Health Survey," 17% of full-time employees work 60 hours or more per week. The desire to secure "free time before bed" due to late returns home exacerbates the delay in going to bed.

5-3. Challenges in the Educational Field

In regions where early morning zero period classes and morning club activities remain in middle and high schools, chronic sleep deprivation is worsening. 83% of parents reported that "advising children against staying up late has little effect."

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6. Background Factors: Digital Dependency, Culture, Biology

1. Blue Light and Melatonin Suppression

   Light from LEDs and smartphone screens suppresses the secretion of the sleep hormone melatonin, delaying the body clock.
   
   

2. "Creating a Place" during Late Night

   There is a strong cultural element of securing "personal time" after the family has gone to sleep.
   
   

3. Social Jetlag

   The habit of catching up on sleep during weekends disrupts the biological rhythm and further promotes a night owl tendency.

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7. Self-care Strategies for Improvement

Improvement Measures	Specific Methods	Effectiveness Measurement Indicators
Digital Detox	Turn off smartphones and PCs 60 minutes before bedtime	Reduction in Sleep Onset Latency
Environmental Adjustment	Indirect lighting + room temperature around 23 ℃	Decrease in Nighttime Awakenings
Relaxation Habits	Stretching and 10-minute Meditation	Decrease in Bedtime Procrastination Index
“Bedtime Preparation Reminder”	Notification 90 minutes before bedtime via smartwatch	Advancement of Actual Bedtime

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8. Examples of Initiatives in Companies and Educational Institutions

• IT Company A: Introduced flextime, expanding the possible start time to 7:00-11:00. Average sleep time increased by 0.4 hours.

• High School B: Conducts a "Digital Free Day" once a month. Students store their smartphones in school lockers and are encouraged to turn off lights at home by 22:00. The rate of sleep delay among students improved from 15% to 9%.

• Municipality C: Disconnects Wi-Fi in libraries after 21:00, encouraging night study to take place at home rather than in library spaces.

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9. Expert Comments and Future Research Tasks

Carson from the University of Utah states, "We are planning an experiment to apply cognitive behavioral therapy for insomnia (CBT-I), which reduces negative emotions, to tackle bedtime procrastination." In Japan, the Department of Psychiatry at Keio University is advancing clinical trials of an online intervention program, with results expected to be published in 2026. Moving forward, AI predictive models integrating digital behavioral data and biometric data will be key.

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10. Conclusion: Balancing Late-night Free Time and Health Risks

Behind the natural behavior of seeking a "mental reward," bedtime procrastination inflates the cost to mental and physical health. If you feel that staying up late has become a habit, start by reviewing your habits 90 minutes before bedtime and reducing digital stimuli. While sleep is often perceived as a matter of "quality" rather than "time," research shows that quality cannot be improved without ensuring sufficient length. To protect your own "sleep assets," try small procrastination countermeasures starting tonight.

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List of Reference Articles

• WEB.DE "Warum spätes Zubettgehen negative Merkmale fördert" (2025-06-10) – Original Article

• Carlson, S. et al. "Depressive and Dysregulated: Examining Personality Factors Among Bedtime Procrastinators." SLEEP (2025)

• EurekAlert! "Study identifies personality traits associated with bedtime procrastination" (2025-06-09)

• American Academy of Sleep Medicine & Sleep Research Society "Recommended Amount of Sleep for a Healthy Adult" (2015)

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Reference Articles