Study Links Both Short and Long Sleep to Faster Biological Ageing

Sleeping too little or too much is associated with faster biological ageing across multiple organs, according to a study published in Nature on 24 August 2026 by researchers at Columbia University Irving Medical Center. The analysis, drawn from roughly 500,000 participants in the UK Biobank, found the lowest rates of biological ageing among people who reported sleeping between 6.4 and 7.8 hours a night.

A U-shaped pattern across the body

The research team applied machine learning to 23 separate biological ageing “clocks” covering 17 organ systems, drawing on medical imaging, organ-specific proteins and blood-based molecular markers to estimate how much faster or slower a person’s organs were ageing relative to their calendar age. Both short sleep, defined as under six hours, and long sleep, over eight hours, were linked to accelerated ageing in the brain, heart, lungs, immune system and other organs, producing a U-shaped curve with the healthiest range in the middle.

“Sleep duration is a deeply embedded part of our entire physiology, with far-reaching implications across the body,” said Junhao Wen, the study’s lead author and an assistant professor of radiology.

Links to chronic disease

Short sleep was separately associated with higher rates of depression, anxiety, obesity, type 2 diabetes, hypertension, heart disease and arrhythmias in the dataset. Both short and long sleep were linked to chronic obstructive pulmonary disease, asthma and digestive disorders, though the authors note the study shows association rather than proven cause and effect, since sleep duration was self-reported by participants.

Why It Matters

Sleep guidance has traditionally focused on a single target, commonly eight hours, but this large-scale analysis adds to evidence that a fairly narrow range in the high sixes to high sevens may matter more for long-term organ health than blanket rules of thumb suggest. For a public health issue affecting nearly everyone, findings of this scale give doctors and policymakers a more precise basis for sleep advice.