Finding the Sleep Sweet Spot: 6.4–7.8 Hours Linked to Slower Biological Aging

A large international study using 23 aging clocks across organs and UK Biobank data finds that both too little (<6 hours) and too much (>8 hours) sleep are associated with faster biological aging and higher mortality, with an optimal window roughly 6.4–7.8 hours. Short sleep links to cardiovascular, metabolic, and psychiatric risks, while long sleep clusters with brain-related conditions; the depression pathways differ between the two sleep patterns. The findings come from MRI, blood proteins, and metabolite data, highlighting sleep’s broad impact beyond the brain.