The Case : Japanese Poor Sleep (2/2)

บทความที่ 2. ผลสำรวจคุณภาพการนอนใน Stressed Workers

A Summary of research study about sleep quality among stressed workers in Japan: Article number: 22620 (2024)

Key Findings:

• The study examined 73 Japanese workers with high occupational stress, using Apple Watches to track their sleep patterns and measuring salivary IL-6 (an inflammatory marker) levels
• Higher levels of IL-6 were associated with shorter durations of slow-wave sleep (N3 or "deep sleep")

💡 Based on the paper, IL-6 (Interleukin-6) is a biological marker that indicates immunological stress response in the body. Here are the key points about IL-6 from the research:

Role as a Stress Marker:

• IL-6 serves as a suitable non-invasive biological marker for stress responses
• It can be measured through saliva samples, making it practical for research
• IL-6 levels increase during chronic stress conditions

Relationship with Inflammation:

• IL-6 is a pro-inflammatory cytokine (immune system signaling molecule)
• Elevated IL-6 levels can cause neuroinflammation in the brain
• Chronic inflammation involving IL-6 is common in various mental and physical illnesses

Impact on Sleep:

• Higher IL-6 levels were associated with shorter durations of deep sleep (N3 sleep)
• IL-6 can disrupt sleep patterns, particularly in the first half of sleep
• The relationship appears to be specific to N3 sleep, as IL-6 levels weren't significantly associated with other sleep stages

Mechanism:

• IL-6 can affect neurotransmitter systems in the brain, including glutamate, serotonin, and orexin
• These changes can influence both sleep architecture and wakefulness
• IL-6 may interfere with the transition from light sleep to deep sleep

Normal Levels:

• In this study, the median IL-6 level among participants was 4.5 pg/ml
• Levels can vary based on stress and other factors
• The study measured IL-6 through saliva samples rather than blood tests

The researchers note that while IL-6 elevation can be influenced by various factors, its relationship with sleep quality suggests it could be an important marker for monitoring stress-related sleep disturbances in workers.

• Poor sleep quality was also linked to greater daytime sleepiness
• The average estimated N3 time was comparable to normal population levels measured by traditional Polysomnography.

Methodology:

• Participants wore Apple Watches for one week to track sleep patterns
• Saliva samples were collected to measure IL-6 levels
• Researchers used validated questionnaires to assess job stress, sleep quality, and other factors
• The study specifically recruited office workers reporting high levels of occupational stress

Significance:

• This is one of the first studies to examine sleep quality in stressed workers using wearable technology in a natural setting
• The findings suggest that biological stress responses (measured by IL-6) may interfere with quality sleep
• Understanding these connections could help develop better interventions for workplace stress and sleep issues

Limitations noted:

• Cross-sectional design couldn't determine causation
• Some technical issues with data collection initially
• Did not assess sleep apnea as a potential confounding factor
• Focused only on stressed workers, so can't compare to less stressed populations

The researchers conclude that managing stress levels may be important for maintaining healthy sleep patterns among workers experiencing high occupational stress.

This study adds to our understanding of how workplace stress affects sleep and suggests potential biological mechanisms that could be targeted for intervention.