Research Shows Sleeping 6.4 to 7.8 Hours a Night May Help Slow Aging

From verywellhealth.com

By Mira Miller

Key Takeaways

• Sleeping between 6.4 to 7.8 hours a night is linked to the slowest biological aging across multiple organ systems.
• Too little sleep (less than 6 hours) and too much sleep (more than 8 hours) can accelerate biological aging through different pathways.

Getting enough sleep is an essential part of staying healthy throughout the lifespan. New research suggests that the ideal amount is between 6.4 to 7.8 hours, while getting either more or less than is associated with increased biological aging.

                                                 Sleeping too much or too little may speed up aging.   Peera_Sathawirawong / Getty Images

What the Research Shows

Researchers conducted the study, published in Nature, by analysing self-reported sleep data from half a million participants in the UK Biobank and comparing it with data about their biological age. Biological age refers to how slow or fast their organs are aging compared to their actual chronological age.

The researchers found that sleeping between 6.4 to 7.8 hours was associated with the slowest biological aging across multiple organ systems, including the brain, liver, lungs, immune system, skin, adipose tissue, and pancreas.

"This study suggests that sleeping too little or too much can accelerate biological aging," said Karen Lincoln, PhD, a professor of environmental and occupational health at UC Irvine Joe C. Wen School of Population & Public Health. "It also confirms that sleep is foundational to healthy aging."

Specifically, researchers identified a consistent U-shaped relationship between sleep duration and biological aging, meaning biological aging is lowest in the middle range and increases at both extremes of sleep duration.

Too little sleep is defined as fewer than 6 hours, while too much is defined as more than 8.

Why Does Sleeping Too Much or Too Little Matter?

Shorter and longer sleep duration have distinct biological pathways, Lincoln explained. She said short sleep is a direct driver of accelerated biological aging as it's associated with heightened physiological stress, systemic inflammation, immune dysregulation, and metabolic disruption which can affect cardiovascular, metabolic, musculoskeletal, and neuropsychiatric systems. 

Long sleep, on the other hand, appears to be more concentrated in brain-related and neuropsychiatric outcomes, like depression or cognitive issues, she said. It might be a marker of underlying disease that the body is already managing, or an adaptive response to stress, rather than a direct driver of accelerated aging.

"The findings reinforce that sleep duration isn’t just a lifestyle choice, it is a biological signal," said Joseph Dzierzewski, PhD, a sleep scientist who directs the scientific mission of the National Sleep Foundation. "Deviating too far in either direction can reflect or contribute to accelerated aging across the body."

Where the Study Falls Short

The study does have an important limitation worth noting, Lincoln said: it relies on a single, self-reported measure of sleep by asking participants how many hours they sleep per day, on average.

But Lincoln said sleep is multidimensional and there are a wide range of measures to determine one’s sleep health. For example, sleep regularity measures whether you’re going to bed and waking up at the same time every day, sleep latency measures how long it takes you to fall asleep after you go to bed, and sleep disruptions include whether you have difficulty falling back to sleep after waking up at night.

Sleep disorders like sleep apnoea also impact many adults and are disproportionately underdiagnosed and untreated in many Black Americans, she added.

"While the number of hours you sleep is important, it doesn’t capture sleep quality and represents only one slice of a much richer picture of sleep health," she said.

What It Means For You

Despite the limitations, Dzierzewski said the results provide a biological stamp of approval for the National Sleep Foundation’s widely cited sleep duration recommendations, which state that most adults need 7 to 9 hours of sleep per night and most older adults need 7 to 8 hours of sleep per night.

"The NSF ranges remain the right target for overall health and well‑being," he said. "If your goal is specifically to support healthy biological aging, this study suggests that consistently sleeping in the 7–8 hour zone may be especially protective."

While this may be true for most people, everyone is different, so Lincoln said it's most important to gauge how you feel when you wake up.

If you feel rested, restored, and energised, she said you are likely getting enough sleep, regardless of whether the clock says 6.5 or 7.5 hours. But if you consistently wake up tired, foggy, and have low energy, that is a signal worth paying attention to, even if your sleep duration is within that recommended range.

"Sleep is essential for healthy aging: your brain clears metabolic waste, your immune system recalibrates, and your organ systems repair during sleep," she said. "Good sleep quality is important for your health no matter how you measure it."

https://www.verywellhealth.com/sleeping-hours-and-aging-11978844 

Is 7 Hours of Sleep Enough?

From healthcentral.com

Too much—or too little—shuteye can lead to serious health problems. Here’s what the experts say about how much sleep adults really need 

When it comes to how many hours of shuteye you get on average, the common recommendation for most adults is to clock at least seven hours each night, and that’s a solid general guideline, says Alex Dimitriu, M.D., a sleep medicine specialist and the founder of Menlo Park Psychiatry & Sleep Medicine in California.

However, it’s helpful to keep in mind that sleep duration can fluctuate based on things like age, lifestyle, illness recovery, pregnancy, or even existing underlying health conditions that you may, or you may not be, aware of.

“For most adults, seven hours is the minimum needed to function well, with nine hours as the maximum, but individual needs can vary quite a bit,” Dr. Dimitriu notes.

The most important thing to understand about sleep? Getting too few—or too many—ZZZs is strongly correlated with potential health issues, he notes. Frequently falling outside the seven-to-nine hour per night sleep window may not always be the cause of those problems, he adds, but can sometimes be an indication that something deeper may be going on. With that in mind, are you getting enough shuteye? Too much? We unpack what the science shows so you can rest easy.

Sleeping Seven to Nine Hours Is the Sweet Spot

Although your individual sleep needs may vary within the seven-to-nine hour timeframe recommendation, there is ample evidence that regularly sleeping less, and also sleeping more, may be detrimental to health, agrees Evin Jerkins, D.O., a sleep medicine specialist at Fairfield Healthcare in Lancaster, OH.

“At this point, there’s a large amount of evidence suggesting sleeping less than six hours a night leads to a higher risk of hypertension, type 2 diabetes [T2D], obesity, coronary artery disease, and stroke,” he explains. Regular shortened sleep can also have effects on mental health and is linked to higher risk of anxiety, depression, and problems with emotional regulation, according to 2025 research published in the American Journal of Lifestyle Medicine.

Consistently sleeping too little health risks because the body and brain go through crucial restorative processes during sleep phases, says Dr. Jerkins. For example, you'll experience higher levels of cortisol—the “fight or flight” hormone—without enough sleep, which can then elevate blood pressure and inflammation in the body. Sleep also plays a key role in brain health, since it's the time when new pathways are formed, waste is cleared, and memory is consolidated.

Regularly oversleeping, on the other hand, which is defined as getting more than nine hours of sleep per night, is also potentially harmful to your health. Took much shuteye is associated with the very same risks—including heart disease and T2D—that is seen with sleeping too little, per Johns Hopkins Medicine.

But, if not enough sleep is wreaking havoc on your body and mental health, wouldn’t “catching up” on your ZZZs be a good thing? Not so fast. Sleeping nine-plus hours per night can disrupt the body’s natural circadian rhythm, which in turn has been linked to higher inflammation and changes to metabolism. Also known as your body clock, your circadian rhythm regulates numerous physiological processes, including your immune response and brain function, according to research in Frontiers in Cellular and Infection Microbiology. When inflammation rises due to this rhythm being thrown off, it can affect how well your immune system works, proper hormone regulation, and your ability to stay alert all day.

“While there is no magic number for sleep … seven to eight hours is the sweet spot for most healthy adults,” Dr. Jerkins confirms. “If you’re consistently getting too few or too many hours of sleep, that doesn’t necessarily mean you have a health issue that leads to sleep disruption or insomnia. But it's important to see your doctor to rule out a serious condition that may be affecting your sleep,” he advises.

Sleep Needs Can Change With Age

A major variable in sleep needs is age, says Dr. Dimitriu. Older adults need the same amount of sleep as younger people but often get less total sleep at night, he explains. This can be due to several factors, such as:

• Chronic illness. Numerous age-related diseases can cause both sleep disruptions or chronic fatigue, including arthritis, osteoporosis, and Alzheimer's disease.

• Menopause-related hormone changes. Night sweats from oestrogen loss can disrupt sleep.

• Side effects of certain medications. Older adults tend to be on a higher number of medications, and some common drugs can disrupt sleep including beta-blockers, antidepressants, inhaled asthma drugs, and diuretics that are used to manage blood pressure.

• Sleep disorders. Insomnia, sleep apnoea, and movement issues such as restless legs syndrome are more common as people age, per the National Institute of Aging.

Yet, while many things can disturb sleep as we grow older, clocking those seven to nine hours may be more important than ever. According to the National Institute on Aging, lack of quality sleep can lead to problems with memory, increased risk of falls or accidents, and more stress overall. Research suggests that not sleeping enough, even in middle age, can raise risk of developing dementia later in life.

Because of the importance of quality sleep, it may be necessary to augment night-time sleep with daytime napping, advises Dr. Jerkins, even if that means getting seven to nine hours of sleep within a 24-hour period if you are 65 or older, rather than aiming for that amount in one block overnight. Just be sure to stay within that seven-to-nine hour range, rather than getting too much sleep due to long naps. Also, nap in the late morning rather than late afternoon, so you don't sabotage your bedtime later, he suggests.

Some People Just Need More Sleep

There are some situations where more sleep is necessary, says Dr. Dimitriu. However, those tend to be short-term needs that affect people who are recovering from, or living with, some type of injury or condition. They include:

• Athletes. People who physically push their bodies may need longer recovery time from a major training session or race.

• Chronic community. People with chronic disorders, including autoimmune diseases and cancer, may require more sleep each night.

• People who are healing. Bouncing back from illness or injury may up your need for additional ZZZs.

• Pregnant women. Research suggests that pregnancy is also a time for more sleep, but paradoxically, pregnancy can be rife with significant sleep disturbances due to nausea, heartburn, and back pain. Much like older adults, napping can help add to the total amount of hours for sleep in a 24-hour period.

• Those with mental health conditions. This may include people with depression or bipolar disorder, who need more sleep to improve cognitive function, Dr. Dimitriu says.

• Signs You're Not Getting Enough Sleep

If you’re regularly getting a minimum of seven hours of sleep, and you wake up feeling rested, especially without using an alarm, and you have consistent energy throughout the day, then it's likely you’re hitting your target when it comes to sleep amount, says Dr. Jerkins. Signs that you may need to increase your amount can include:

• Daytime sleepiness

• Difficulty focusing or paying attention

• Emotional regulation problems, such as irritability or anxiety

• Falling asleep very quickly

• Food cravings, especially for carb-filled snacks

• Hard time waking up in the morning

• Increased clumsiness

• Memory issues, including forgetfulness

• More prone to catching common infections, such as cold or flu

• Needing an energy boost like caffeine or sugar to get through the day

• Slower reaction time

“Keep in mind that duration of sleep alone is not the only factor here,” Dr. Jerkins adds. “Quality sleep is also crucial. A good first step for both of those is going to bed and waking up at the same time on weekdays and weekends, to establish a consistent sleep schedule.”

https://www.healthcentral.com/sleep/is-seven-hours-of-sleep-enough

Oversleeping Can Be Bad for Your Health—How to Know if You're Sleeping Too Much

From realsimple.com

Getting too much sleep is anything but a dream 

Many people struggle to get enough sleep throughout the week due to stress, insomnia, overstimulation, and more. What results is a smattering of less-than-ideal side effects the following day. “Typical symptoms of inadequate sleep can include feeling unrefreshed, even as the day progresses, and finding it hard to stay awake during the day,” says Martin Reed is the founder of Insomnia Coach.

However, others deal with the exact opposite issue—namely oversleeping. While plenty of us would only hope to have the time and ability to oversleep, this condition can also have negative health implications on one’s day-to-day life. Below, we will help demystify what oversleeping is, how it impacts our health, and ways to stop oversleeping (if you fit within that category).

What is Oversleeping?

First things first, what exactly qualifies as oversleeping?

“If someone regularly sleeps for longer than nine or 10 hours and still feels tired during the day, they might be experiencing oversleeping,” says Reed. Though, he explains that since sleep needs vary from person to person, sleeping for longer durations is only a problem if it interferes with someone’s ability to engage in daily functions and accomplish what they set out to do in everyday life.

Oversleeping, also known as ‘long sleeping,’ is alternatively defined as regularly sleeping over 10 hours per day, above the National Sleep Foundation’s recommendation of seven to nine hours for adults between the ages of 18 and 64.

How to Tell if You’re Oversleeping

Oversleeping can be a single occurrence, like if you’re catching up after a hectic week or a strenuous event. “Oversleeping might also happen as a side-effect of certain medications, or when we are unwell or recovering from being unwell,” says Reed. 

However, oversleeping can also be a chronic condition. Reed explains that chronic oversleeping can be a symptom of another pre-existing health concern, like sleep apnea, delayed sleep phase syndrome, or hypersomnia. 

While some regular oversleepers may be quick to diagnose themselves with hypersomnia, this rare condition is characterized by “excessive daytime sleepiness, uncontrollable need to sleep with long unrefreshing naps, and difficulty waking up from sleep in most instances despite average or longer amounts of nocturnal sleep for at least three months,” according to the National Institutes of Health.

Certain diagnoses like narcolepsy, Parkinson’s disease, Kleine-Levin syndrome, restless leg syndrome, chronic pain, and traumatic brain injury can also lead to oversleeping. “People suffering from depression might be more likely to spend longer periods of time in bed, too,” says Reed. Though, the best way to know for sure if you’re oversleeping is to visit your healthcare provider.

                                                                                        Photo:  Gizela Glavas / Getty Images

Is Oversleeping Bad?

While oversleeping may sound like a dream (pun intended) for some, engaging in this sleep behaviour over long periods of time can pose some significant health concerns. “Oversleeping can make you feel more tired if you don’t have a consistent sleep schedule, because big variations in when we get out of bed to start the day can disrupt the body clock, making it harder for the body to regulate wakefulness and sleepiness,” says Reed.

Whether you oversleep on rare occasions or chronically, the habit can have a smattering of health effects, especially on your mood. Some may experience anxiety, fatigue, irritation, agitation, memory problems, and brain fogginess. Additionally, since our circadian rhythms also influence hunger cues, those who oversleep may report having either increased or decreased appetite, which could influence body weight.

However, chronic oversleeping can have some additional, more concerning health implications. According to a 2018 clinical review of over five million participants from over 130 prospective cohort studies published in Sleep Medicine Reviews, long sleep was significantly associated with diabetes, heart disease, stroke, obesity, and increased mortality risk. Johns Hopkins also notes that oversleeping can increase risk for depression and headaches.

How to Stop Oversleeping

If you think you may fit within the oversleeper category, there are plenty of actions you can take to ensure your sleep health is in tiptop shape. Again, these interventions are best implemented after paying your doctor a visit to rule out any underlying medical causes for oversleeping.

“If there is no medical explanation, some behavioural changes that might help include having a consistent out-of-bed time in the morning by putting an alarm clock on the other side of the room, or making morning plans that require you to get out of bed by a certain time, as well as being active during the day and spending time outside,” says Reed.

Avoiding blue light and sleep-disrupting nutrients like caffeine, alcohol, added sugar, and diuretics before bed can also encourage more restful sleep, decreasing the chance that interrupted sleep is leading to oversleeping habits.

Research has also shown that cognitive behavioural therapy may be supportive in alleviating oversleeping symptoms, particularly if they are related to conditions like depression. Certain medications may also help address oversleeping. However, undergoing a sleep study can be one of the best ways to tackle oversleeping, as it provides sleep experts with important data that they can use to provide a more tailored treatment approach.

The Bottom Line

Although many of us would love the opportunity to oversleep, the condition can pose nearly as many adverse health effects as undersleeping. While one-off nights of oversleeping aren’t so concerning, chronic oversleeping can allude to either underlying health concerns, or increase our risk for new ones. This is why, in addition to making simple lifestyle changes at home, it’s so important to visit your healthcare provider if you think you may fall under this umbrella.

https://www.realsimple.com/oversleeping-bad-for-your-health-8706246