A new study on biological aging suggests that both too little and too much sleep may be linked to faster aging in the brain, heart, lungs, immune system, and other organs. Researchers also associated these sleep patterns with a broad range of health conditions, including depression, diabetes, heart disease, and respiratory disorders.
“Previous research has shown that sleep is closely associated with brain aging and the accumulation of disease-related changes. Our research goes further by showing that both insufficient and excessive sleep are associated with accelerated aging across nearly every organ,” said study leader Junhao Wen, assistant professor of radiology at Columbia University’s Vagelos College of Physicians and Surgeons. “The findings have important implications for metabolic balance, overall health, and the role of sleep in maintaining organ function within the brain-body network, including the immune system.”
The research was published in Nature.
Biological clocks reveal how organs age
Scientists are increasingly using biological aging clocks to estimate whether a person is aging faster or slower than expected based on their chronological age. These tools use machine learning and biological data, including proteins measured through minimally invasive blood tests, to identify patterns linked to aging.
Many biological aging clocks provide one overall estimate for the entire body. However, individual organs age at different rates. One well-known example is the decline in ovarian function, which contributes to the biological aging process associated with female fertility.
Wen and his colleagues have been developing organ-specific aging clocks to provide more detailed and potentially personalized information about a person’s health.
“Everyone is excited about biological aging clocks and their ability to predict disease and mortality risk,” Wen said. “But to me, the more interesting question is whether we can connect these aging clocks to lifestyle factors and modify them over time to slow biological aging.”
Finding the ideal sleep duration
Sleep offered researchers an effective way to investigate that question because growing evidence shows that sleep duration and sleep quality play important roles in overall health. Wen also had a personal interest in the subject.
“I’m also a light sleeper, so I was concerned about the possible effects on my own health,” Wen said.
To develop the biological aging clocks, Wen and his team analyzed data from approximately 500,000 participants in the UK Biobank. The researchers used machine learning to identify biological features associated with aging in different organs.
The researchers created the aging clocks using several types of information, including structural measurements from medical imaging, organ-specific proteins, and molecules detected in blood samples.
“For example, the liver can have an aging clock based on protein data, another based on metabolic data, and another based on imaging data,” Wen said. “This allows us to determine whether sleep is consistently linked to aging clocks derived from multiple biological and molecular layers.”
The team then compared each participant’s self-reported sleep duration with their estimated biological age. The analysis included 23 aging clocks covering 17 organ systems.
Too little or too much sleep may be linked to faster aging
The researchers identified a distinct U-shaped relationship between sleep duration and biological aging. People who reported sleeping fewer than six hours or more than eight hours per night generally showed signs of faster biological aging.
The lowest levels of biological aging were observed among people who reported sleeping approximately 6.4 to 7.8 hours per day.
However, the study does not prove that sleep duration directly accelerates or slows organ aging. Instead, the findings suggest that consistently short or long sleep may be a marker of underlying health problems or disrupted physiology.
Sleep duration is associated with systemic health conditions
The study also revealed extensive connections between sleep duration, brain health, and the function of other organs.
Short sleep was significantly associated with depressive episodes and anxiety disorders, supporting previous research linking sleep deprivation with mental health challenges.
Insufficient sleep was also associated with obesity, type 2 diabetes, high blood pressure, ischemic heart disease, and cardiac arrhythmias.
Both short and long sleep were associated with chronic obstructive pulmonary disease and asthma. Researchers also identified links with several digestive conditions, including gastritis and gastroesophageal reflux disease.
“Broad patterns across the brain and body are important because sleep duration is deeply integrated into our overall physiology and can affect many systems throughout the body,” Wen said.
Sleep, biological aging, and depression later in life
Organ-specific biological aging clocks may also help researchers better understand how sleep is connected to individual diseases. To explore this possibility, Wen and his colleagues examined the relationship between sleep duration and depression in later life.
The researchers could not determine whether abnormal sleep duration contributes to late-life depression or whether depression changes how long a person sleeps.
To investigate the relationship further, the team used a “mediation analysis” to determine whether biological aging could help explain the connection between short or long sleep and depression later in life.
The analysis suggested that short sleep may be more directly associated with the burden of late-life depression. In contrast, long sleep may affect depression through biological pathways reflected in the aging clocks of the brain and adipose, or fat, tissue.
“These findings have important implications for future sleep management and treatment,” Wen said. “Our study suggests that short and long sleep may involve different biological pathways that lead to the same outcome—depression later in life—and they may require different approaches.”
Source: www.sciencedaily.com