A major new study published in Nature suggests that consistently sleeping less than six hours or more than eight hours may accelerate aging across the brain, heart, lungs, and immune system.
Researchers analyzed data from nearly half a million UK Biobank participants, using machine learning-based “biological aging clocks” to compare chronological age with biological markers like brain scans, blood proteins, and chemical indicators.
The findings revealed a consistent U-shaped pattern: those who slept within the middle range showed the healthiest biological profiles, while short and long sleepers exhibited signs of faster aging across multiple organ systems.
Short sleep was strongly linked to brain-related disorders including depression and anxiety, heart disease, type 2 diabetes, obesity, asthma, and digestive issues like reflux.
Long sleep, while also associated with health problems, may sometimes reflect underlying illness rather than being a direct cause, the researchers noted.
“The broad brain-body pattern tells us that sleep duration is a deeply embedded part of our physiology, with far-reaching implications across the body,” said Junhao Wen, lead author and assistant professor of radiology at Columbia University Vagelos College of Physicians and Surgeons.
Researchers caution the study does not prove sleep alone causes these changes, and that self-reported sleep data may be less accurate than direct measurement. They call for future research using more precise tools and more diverse populations.