Sleep affects not only well-being and cognitive function, but also the rate of aging throughout the body. Both sleep deprivation and excessive sleep are associated with accelerated biological aging of the brain and other organs.
To investigate the relationship between sleep duration and biological aging, an international group of scientists analyzed data from nearly 500,000 individuals in the UK Biobank. The researchers evaluated 23 biomarkers of biological age, including MRI data and plasma protein and metabolite profiles. These markers reflect the extent to which a person’s biological age differs from their chronological age.
The analysis revealed a U-shaped relationship between sleep duration and biological age. The lowest signs of aging were observed in individuals with moderate sleep duration, whereas both short sleep (less than 6 hours) and long sleep (more than 8 hours) were associated with faster tissue and organ aging.
Sleep disturbances were also associated with a higher risk of systemic diseases and all-cause mortality. Importantly, the adverse effects extended beyond the nervous system to include metabolism and cardiovascular health. In addition, both short and long sleep may be linked to late-life depression.
Because sleep duration is a modifiable factor, sleep should be considered an important target for preventing age-related diseases and promoting healthy aging.
Both Short and Excessively Long Sleep Accelerate Biological Aging
The strongest association between sleep duration and biological aging was observed for brain age. U-shaped relationships were also found for the lungs, liver, immune and endocrine systems, skin, adipose tissue, and pancreas.
Women had higher biological brain age measures on average than men, and the optimal sleep duration differed slightly between the sexes.
The lowest biological age values corresponded to sleep durations of:
- 5–7.8 hours in women;
- 4–7.7 hours for men.
Short and Long Sleep Differ in Their Associations With Disease and Mortality
Short sleep was associated with a broad spectrum of diseases, including cardiovascular, metabolic, psychiatric, pulmonary, and gastrointestinal disorders. The strongest associations were observed for soft tissue disorders, bronchitis, low back pain, depression, and substance use disorders. Short sleep was also linked to an increased risk of heart failure, chronic obstructive pulmonary disease, anxiety disorders, migraine, type 2 diabetes, and coronary artery disease.
Long sleep was mainly associated with neurological and psychiatric conditions – including major depressive disorder, schizophrenia, bipolar disorder, ADHD, alcohol dependence, and migraine.
Both short and long sleep were associated with an increased risk of systemic disease development and premature death. The risk of all-cause mortality was elevated by 1.4–1.5-fold in both groups.
Short and Long Sleep Are Linked to Late-Life Depression Through Different Mechanisms
Short sleep was directly associated with late-life depression through stress responses, impaired immune regulation, and neuroendocrine alterations. The researchers linked this effect to systemic inflammation and metabolic disturbances that rapidly affect brain function and emotional regulation.
In contrast, long sleep was indirectly associated with depression through accelerated aging of the brain, adipose tissue, and liver. Changes in the brain accounted for approximately 62% of this effect. This finding suggests that excessive sleep may not always be an independent cause of impairment, but rather a marker of underlying age-related or chronic pathologic processes.
Reference
Sleep chart of biological ageing clocks in middle and late life
