We think of sleep as a chance to recover, but the mechanism is more complex. Nighttime rest is the main regulator of the body's biological age. A new study from Columbia University scientists shows that preserving health requires a specific amount of sleep — no more than 7.8 hours a day. Going outside that range, whether too little or too much, triggers accelerated aging in nearly every internal organ.
Why this norm matters
A research team led by radiology associate professor Zhonghao Wen analyzed data from nearly 500,000 participants in the UK Biobank. The scientists compared people's sleep duration with the pace of biological aging in their bodies.
The results formed a clear pattern.
- Less than 6 hours of sleep: participants' bodies showed substantial acceleration of biological aging compared with calendar age.
- More than 8 hours of sleep: contrary to the popular myth that long sleep rejuvenates, it does not — it similarly drives premature wear on tissues and organs.
- 6.4 to 7.8 hours: this interval proved the «sweet spot,» with the lowest level of biological aging recorded.
How scientists measured the age of individual organs
Instead of assessing the body in general terms, Wen's team used machine-learning algorithms to create 23 separate «aging clocks» covering 17 systems.
For this they analyzed CT scan data, blood protein composition, and metabolic markers. The study showed that the liver, heart, brain, and adipose tissue can age at different rates. Incorrect sleep duration accelerates that process synchronously across the entire neuro-somatic network.
What diseases deviation from the norm can lead to
Improper sleep patterns are directly linked to systemic pathologies throughout the body.
- Consequences of short sleep (under 6 hours): risk rises sharply for depressive episodes, anxiety disorders, obesity, type 2 diabetes, hypertension, coronary heart disease, and arrhythmia.
- Shared risks (sleep deprivation and oversleeping): both extremes are associated with chronic obstructive pulmonary disease (COPD), asthma, and gastrointestinal conditions — gastritis and gastroesophageal reflux disease (GERD).
Different paths to depression in old age
Researchers paid separate attention to the link between sleep and depression in later life. Using mediation analysis, they showed that both too little and too much sleep lead to depression through entirely different biological mechanisms.
Chronic sleep deprivation has a direct destructive effect on psycho-emotional state. Excessive sleep, meanwhile, pushes toward depression indirectly — through degradation and accelerated aging of brain and adipose tissue.
This finding shows that treatment and sleep correction for patients with too little or too much rest should follow completely different medical protocols.
