Interleukin-6 and Its Effects on Sleep
Yes, interleukin-6 (IL-6) is definitively known to affect sleep patterns and quality, with higher levels being associated with sleep disturbances in multiple disease conditions. 1
Mechanisms of IL-6's Effects on Sleep
IL-6 influences sleep through several pathways:
- Circadian Rhythm: IL-6 follows a biphasic circadian pattern with peaks around 19:00 and 05:00, and nadirs around 08:00 and 21:00 in healthy individuals 2
- Sleep Architecture Alteration: Administration of IL-6 has been shown to:
- Decrease slow-wave sleep during the first half of the night
- Increase slow-wave sleep during the second half of the night
- Significantly reduce REM sleep throughout the night 3
- Sleep Latency: Higher levels of IL-6 are independently associated with greater REM sleep latency 4
IL-6 in Sleep Disorders and Inflammatory Conditions
IL-6 plays a significant role in sleep disturbances across various conditions:
- Atopic Dermatitis: Higher daytime and nighttime IL-6 values correlate with poor sleep efficiency 1
- Obstructive Sleep Apnea: IL-6 is elevated in patients with OSA and has been investigated as a potential biomarker 1
- Sleep Restriction: Experimental sleep restriction (4 hours/night) leads to elevated IL-6 levels, which strongly correlate with increased pain sensitivity (r = 0.67, P <0.01) 5
Bidirectional Relationship Between IL-6 and Sleep
The relationship between IL-6 and sleep is bidirectional:
- Sleep affects IL-6: Sleep deprivation or restriction stimulates IL-6 secretion 5, 2
- IL-6 affects sleep: IL-6 is considered a putative "sleep factor" that can influence sleep/wake patterns 2
- Therapeutic implications: IL-6 receptor inhibition with tocilizumab in rheumatoid arthritis patients significantly improves sleep quality, with improvements visible as early as one month into treatment 6
Clinical Implications
Understanding the relationship between IL-6 and sleep has important clinical implications:
- Assessment: Consider inflammatory markers including IL-6 when evaluating patients with unexplained sleep disturbances
- Treatment: Targeting IL-6 pathways may improve sleep in conditions with elevated inflammatory markers
- Monitoring: Changes in sleep patterns may reflect underlying changes in inflammatory status
Potential Pitfalls and Caveats
- IL-6's effects on sleep may vary based on:
- Timing of elevation (acute vs. chronic)
- Concurrent levels of other inflammatory mediators
- Underlying health conditions
- Age (circadian pattern of IL-6 becomes flattened in older individuals) 2
- The relationship between IL-6 and sleep quality is complex and may be influenced by cortisol levels, which can determine whether IL-6 contributes to sleepiness and deep sleep (with low cortisol) or feelings of tiredness and poor sleep (with high cortisol) 2
In conclusion, IL-6 is a significant mediator of sleep processes, and its dysregulation can contribute to sleep disturbances across various conditions. Targeting IL-6 pathways may represent a therapeutic approach for improving sleep in inflammatory conditions.