Persistent Partial Sleep Deprivation Linked to Increased Inflammatory Markers

Restricted sleep for multiple nights is associated with a significant increase in systemic markers of inflammation in healthy adults, according to findings from a study published in the Journal of Sleep Research.

Although sleep is known to affect immune function, the inflammatory effects of experimental sleep deprivation remain unclear. To address this gap, researchers conducted a systematic review and meta-analysis of 35 studies involving 887 healthy adults, examining how total and partial sleep deprivation over 1 or multiple nights impacts circulating inflammatory markers, including interleukin-6 (IL-6) and C-reactive protein (CRP).

The researchers searched PubMed, Scopus, PsycINFO, and CINAHL databases for studies on post-deprivation concentrations of IL-6, CRP, and other cytokines like tumor necrosis factor-alpha (TNF-α) and IL-1β. Studies were stratified by type (total or partial) and duration (single or multiple nights) of sleep deprivation.

Across included studies, mean (SD) participant age was 26.93 (3.8) years, and 26.88% of participants were women. A majority of studies used within-subject designs and assessed inflammatory markers via plasma or serum samples.

The researchers found that 1 night of sleep deprivation, either total or partial, did not significantly affect IL-6 or CRP levels. However, restricting sleep to approximately 4.5 hours per night over multiple (mean duration, 8.3) nights was associated with significant increases in IL-6 (D =0.42; 95% CI, 0.11-0.73; P <.01) and CRP (D = 0.76; 95% CI, 0.09-1.43; P =.03). Inflammatory effects of partial sleep deprivation were not detected until at least 3 nights of restricted sleep had occurred, suggesting a delayed response in cytokine production. No significant effects were observed for TNF-α or IL-1β under similar conditions.

Study limitations include non-randomized, non-blinded designs, small sample sizes, and a predominance of young, male participants. Additional issues include inconsistent confounder reporting and heterogeneity in sleep protocols, although most studies used validated outcomes and appropriate statistical methods.

“If replicated in robust randomised controlled trials, our results would strengthen the need to include habitual sleep duration in the clinical assessment of individuals at risk of inflammation-related conditions (e.g., autoimmune diseases, cardiovascular disease) and to target persistent short sleep duration with appropriate interventions,” the study authors concluded.