Overview
- An international team analyzed nearly 500,000 UK Biobank participants with 23 machine-learning aging clocks built from brain and organ scans, blood proteins, and chemical markers.
- People sleeping under six hours or over eight had faster biological aging and higher death risk, with hazards rising about 50% for short sleepers and 40% for long sleepers.
- The slowest aging clustered around 6.4 to 7.8 hours a night, with small shifts by organ and by sex.
- Short sleep linked to heart disease, high blood pressure, type 2 diabetes, obesity, kidney problems, and mood disorders, while long sleep was more tied to major depression, bipolar disorder, and schizophrenia.
- The authors cautioned the findings show associations based on self-reported sleep and urged trials with objective sleep tracking before changing public guidance.