“Sleep chart of biological ageing clocks in middle and late life” [Nature]. (Sorry, kids. When there is a study for you, I will be sure to publish it). From the Discussion section:
By using large-scale multimodal data from the MULTI Consortium, we demonstrate that both short (<6 h) and long (>8 h) sleep duration are linked to elevated biological ageing burden across seven organ systems and three omics types. Importantly, our findings extend previous work on phenotype-based ageing clocks by showing that this nonlinear sleep–ageing relationship generalizes across the body and is evident not only in structural and functional imaging features but also at the molecular level. This is the first study, to our knowledge, that reveals a broad agreement between sleep duration and multi-organ, multi-omics ageing clocks and links these signatures to systemic disease outcomes and mortality risk. Our results underscore the systemic biological adverse associations of disturbed sleep and provide a compelling framework for more targeted and thoughtful attention to sleep disturbance as a potential signal of emerging health issues and a partner in the quest to promote healthy ageing, reduce disease risk and extend lifespan.
A key contribution of this study lies in identifying consistent U-shaped associations between sleep duration and organ-specific biological ageing clocks across diverse organs, tissues and omics1 data types. At the molecular level, we observed that both short and long sleep duration are associated with accelerated pulmonary, brain, hepatic, immune and skin ProtBAGs, suggesting that proteomic signatures of ageing in these systems are particularly sensitive to sleep perturbations. These findings support sleep’s systemic implications on immune–inflammatory processes28, metabolic detoxification29 and neurodegenerative pathways30.
Thing is, I buy the claims of historians and anthropologists that other cultures, including the West in medieval times, had a “two sleeps” pattern. So what does that do for the U-shape? Are we to characterize the sleeping pattern of an entire continental civilization as “disturbed”? At the molecular level?
1 Allen Institute:
“Omics” refers to a branch of research in the biological sciences focused on studying all of a particular type of molecule found within a living system. This research includes techniques that share the suffix of -omics:
- Genomics: studying all of the genes within a genome
- Transcriptomics: studying all of the RNA within a cell
- Proteomics: studying all of the proteins within a cell