A new study indicates that both insufficient (under 6 hours) and excessive (over 8 hours) sleep can accelerate aging in various organs and is linked to several diseases. Analyzing data from nearly half a million participants in the UK Biobank, researchers found that those who slept within the 6-8 hour range exhibited the healthiest biological aging. The study highlights the importance of sleep duration in overall health, but cautions that it cannot definitively prove causation.