6.4 to 7.8 Hours a Night May Slow Biological Aging

• A recent study found that too little or too much sleep may speed aging in the brain and other organs.
• The study used aging clocks to examine associations between sleep and various mental health and medical conditions.
• The researchers also found a direct link between sleep and late-life depression.

Sleep is an important aspect of overall health and emotional well-being. The amount and quality of sleep you get can affect your body in various ways.

A recent study published in Nature found that getting too little or too much sleep may speed aging in the brain and other areas of the body.

Previous research has linked low sleep to faster brain aging. This study, however, takes that further and shows an association between the amount of sleep you get and the aging of nearly every organ.

“Sleep is fundamental for healthy aging and longevity. More importantly, it is potentially modifiable,” said lead study author Junhao Wen, PhD, assistant professor of radiological sciences at Columbia University. “In this study, we measure biological aging clocks across organs to link these clocks with sleep duration,” Wen told Healthline.

Chronological age is the number of years you have been alive. Biological age measures how quickly your cells and tissues are aging.

Studies like this examine biological aging and the various factors that can affect it.

Aging clocks have become increasingly popular in these types of studies. These clocks are scientific, computational models that estimate a person’s biological age and how they are aging faster or slower than their chronological age. These estimates are based on biological data from the individual.

Most aging clocks measure age across the whole body. However, organs may age at different rates. The research team behind the study has been instrumental in developing aging clocks for specific organs. These clocks can provide more specific and personalized information to individuals.

The study used data from half a million participants in the UK Biobank and machine learning to identify signatures of aging in the organs.

The researchers then assessed the relationship between a person’s self-reported sleep duration and their biological age, using 23 aging clocks across 17 organs.

The study defined too little sleep as less than 6 hours and too much sleep as more than 8 hours.

They found that, in general, people who slept too little or too much showed signs of faster biological aging than those who reported sleeping between 6.4 and 7.8 hours each day.

It is important to note that this doesn’t mean that your sleep duration alone causes organs to age faster or slower. However, it does suggest that both too little or too much sleep may play a role in poorer overall health across your body.

“Short sleep duration is associated with immune dysregulation and increased systemic inflammation, impairing tissue repair and metabolic homeostasis. It also disrupts glucose regulation and overall energy balance,” said Sarathi Bhattacharyya, MD, pulmonologist, sleep medicine specialist, and medical director of MemorialCare Sleep Disorders Center at Long Beach Medical Center in Long Beach, CA. Bhattacharyya wasn’t involved in the study.

“Additionally, insufficient sleep increases sympathetic nervous system activity, which may contribute to accelerated cellular aging across multiple organ systems,” he told Healthline.

Bhattacharyya noted that too much sleep can have adverse effects. “Prolonged sleep duration may be associated with similar adverse aging outcomes,” he said. “In many cases, longer sleep may reflect underlying or subclinical pathology that itself contributes to accelerated aging.”

The study showed a relationship between sleep and chronic diseases. This suggests that a connection exists beyond brain influence.

Too little sleep was associated with brain disorders like depression and anxiety disorders. An association was also found between short sleep and medical conditions, such as:

“Short sleep is often more associated with stress of a busy lifestyle, and anxiety. It can lead to elevated blood pressure, cortisol, and blood glucose levels, which all have detrimental effects over time,” said Alex Dimitriu, MD, a double board certified psychiatry and sleep medicine specialist and founder of Menlo Park Psychiatry & Sleep Medicine in California. Dimitriu wasn’t involved in the study.

“Longer sleep is associated with depression, but more so [with] illness of the body. People who are sick or unhealthy may thus require more sleep than 8 hours per night. For long sleepers, it is more likely that illness causes longer sleep, rather than longer sleep causing illness,” Dimitriu told Healthline.

The organ-specific aging clocks from this study may also be useful for determining how sleep is related to specific conditions.

For example, this study used them to look more closely at how sleep may be associated with late-life depression.

The study could not definitively determine whether sleep duration directly caused late-life depression or whether late-life depression influenced sleep duration. However, the researchers did apply mediation analysis to late-life depression.

With this, they examined whether aging clocks mediate the relationship between sleep and late-life depression. Their analysis suggests that too little sleep may directly influence the disease burden of late-life depression. Too much sleep may influence late-life depression via a mediation pathway that underlies the brain and adipose clocks.

Wen said that the study’s findings may impact future sleep research and management.

“One should manage sleep optimization in a systematic way that considers his/her medical history because we observed a different sleep-organ U-shaped pattern. Also, doctors should treat long sleepers and short sleepers differently, as shown in Fig.4’s mediation analyses between short/long sleep vs. late-life depression,” he said.

Quality sleep is important for overall health.

“Despite the 7-hour ideal sleep time, give yourself a window of at least 8 hours to sleep. Aim for 8, by eating earlier, slowing down earlier, turning off screens earlier, so you can actually get about 7 quality hours of sleep,” Dmitriu said.

Bhattacharyya said that optimal sleep requires appropriate management of underlying medical and psychiatric conditions, as well as environmental and behavioral factors.

“Maintaining a consistent wake time is particularly important for stabilizing circadian rhythm. Adherence to good sleep hygiene — especially during the evening wind-down period — is also essential,” he said.