Study Finds Surprising Link Between Sleep & This Common Joint Issue

From mindbodygreen.com

By Zhané Slambee

Sleep rarely comes up in conversations about joint health. Most guidance focuses on weight management, exercise, and avoiding injury, and for good reason.

But a large new study suggests that what happens at night may matter more for your joints than previously understood.

Researchers analysed data from nearly 500,000 adults and found that short sleep, frequent insomnia, and night shift work were all independently linked to a higher risk of developing osteoarthritis (OA), a degenerative joint disease and needing joint replacement surgery. And many of those associations held even after accounting for body weight. 

                                                                          Image by Addictive Creatives / Stocksy

About the study

Osteoarthritis develops when the cartilage cushioning your joints breaks down over time. It's driven by a mix of factors: joint injury, metabolic changes, aging, and genetics. But researchers have been looking more closely at another possible contributor—disruptions to your body's internal clock, or circadian rhythm.

Cartilage goes through daily cycles of stress and recovery. During the day, it absorbs load and metabolic demand. At night, it recovers; rebuilding thickness and water content. 

The cells that make up cartilage (called chondrocytes, which is the only cell type found in cartilage) follow their own internal daily rhythm, which helps coordinate that repair process. In animal studies, disrupting the circadian clock led to cartilage breakdown similar to what's seen in OA. 

To see whether that pattern holds in people, researchers at Washington University used data from the UK Biobank, a large prospective study of approximately 500,000 adults in the United Kingdom recruited between 2006 and 2010. Participants (median age 58, 54% female) answered baseline questions about their sleep duration, how often they experienced trouble falling or staying asleep, and whether they worked shifts.

Researchers then tracked four outcomes over the following 8 to 13 years: knee OA, hip OA, total knee replacement, and total hip replacement.

Short sleep, insomnia, & night shifts all raised OA risk

People sleeping fewer than six hours a night had a 41% higher risk of knee OA and a 31% higher risk of needing a knee replacement compared with those sleeping seven hours. 

For the hip, the numbers were similar—39% higher risk of hip OA and 21% higher risk of hip replacement.

People who "usually" had trouble falling asleep or staying asleep had a 34% higher risk of knee OA and a 40% higher risk of knee replacement compared with those who "never or rarely" experienced those problems. 

Similar increases were seen for hip OA (30% higher risk) and hip replacement (24% higher risk).

Night shift workers, specifically those working through the hours of 12 a.m. to 6 a.m., had a 24% higher risk of knee OA and a 28% higher risk of knee replacement compared with people who didn't work shifts.

Night shift work was not significantly linked to hip OA or hip replacement, a pattern the researchers note is consistent with animal research: when the circadian clock gene BMAL1 (a key protein that helps regulate the body's internal clock) is knocked out in mice, cartilage in the knee breaks down, but not in the hip.

Why the associations held even after controlling for weight 

We've always thought that poor sleep raises OA risk mainly because it contributes to weight gain, which then puts more stress on your joints. But the data here tell a more complicated story.

After accounting for body weight, all of the associations weakened but didn't disappear. People sleeping fewer than six hours still had a 31% higher risk of knee OA and a 20% higher risk of knee replacement. Insomnia remained linked to all four endpoints. Night shift work remained linked to knee OA and knee replacement specifically.

The researchers also ran a separate analysis excluding anyone who already reported at least three months of knee or hip pain at the time of their sleep assessment. This was to rule out the possibility that people were sleeping poorly simply because they were already in pain.

The associations held there too.

Why knees may be especially vulnerable

Across all three sleep factors (duration, insomnia, and shift work) the signal was strongest and most consistent for the knee. The researchers offer a few explanations.

The knee may depend more heavily on a functioning circadian clock than the hip does, partly because of differences in how the two joints are structured and how hip OA tends to develop (often through issues like hip dysplasia or impingement).

Weight also plays a bigger role in knee OA than hip OA, and disrupted sleep likely influences the knee partly through that pathway.

One other pattern stood out: among night shift workers whose jobs rarely or never required heavy physical labour, the risk increases were even larger; 43% higher knee OA risk and 40% higher knee replacement risk.

The researchers suggest that circadian disruption may have the biggest impact on people who don't already have elevated OA risk from physical wear on the job.

Sleep habits worth building for your joint health long-term

Circadian rhythms and sleep can be improved through lifestyle changes and sleep hygiene. This points to new potential ways to reduce OA risk before joint pain ever develops. Here are strategies worth considering:

Keep a consistent sleep schedule: Seven hours appears to be the protective threshold in this data. Going to bed and waking at the same time every day helps anchor your body's internal clock.

Get morning light exposure: Light is one of the most powerful cues for setting your circadian rhythm. Getting outside in the first hour after waking helps your body clock stay on track.

Limit artificial light at night: Dimming screens and lights in the hours before bed supports your body's natural melatonin production and helps protect your sleep timing.

Address insomnia early: Frequent insomnia was linked to risk increases comparable to (and in some cases greater than) sleeping fewer than six hours.

If you work night shifts, minimize circadian disruption where you can: Changing your schedule may not be an option, but strategies like timed light exposure, strategic napping, and keeping a consistent routine on days off can help reduce the mismatch between your internal clock and your work hours.

The takeaway

This large prospective study found that sleeping fewer than six hours, experiencing frequent insomnia, and working night shifts were all linked to higher osteoarthritis risk (particularly at the knee) even after accounting for body weight.

The findings suggest that sleep quality and circadian health may be modifiable risk factors for OA, alongside the more commonly discussed pillars of exercise and weight management.

https://www.mindbodygreen.com/articles/poor-sleep-could-be-quietly-raising-your-osteoarthritis-risk-study-finds 

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 

Why does your sleep change as you get older?

From irishnews.com

Many people have problems dropping off as they age, but disrupted nights shouldn’t be inevitable – here, experts suggest solutions that may help

There are many disadvantages to getting older – and one of them is poor sleep.

The British Geriatrics Society says approximately 40% of people aged 65 and over experience insomnia regularly, with up to 75% suffering from some form of sleep disturbance.

But in the approach to World Sleep Day (March 13), the good news is that although there are many reasons why sleep may deteriorate as you age, it doesn’t have to be that way.

“Fundamentally, your sleep doesn’t have to change in your 60s or 70s, but circumstances tend to create a lot more vulnerability around that ageing point,” says Professor Jason Ellis, director of the Northumbria Centre for Sleep Research at Northumbria University.

“A lot of the challenge  we have for older adults is they’re being taught this is normal – ‘Oh, it’s normal that you shouldn’t sleep well, just as it’s normal you should have aches and pains’. That’s not true. The vulnerability is there, but it’s not a fait accompli. It doesn’t mean that every older adult shouldn’t have good sleep.”

And Lisa Artis, deputy CEO of The Sleep Charity, adds: “It’s important to stress that poor sleep is not an inevitable part of ageing. While sleep patterns change, persistent sleep difficulties shouldn’t simply be accepted as ‘just getting older.’”

Increasing vulnerabilities

Both experts agree that certain vulnerabilities make older people more susceptible to sleep problems, and Ellis explains: “Once we hit our 60s, we’ve got a lot of things that increase vulnerability – illnesses, medications, multiple losses, those things can create more vulnerability to sleep problems.

“Similarly, we tend to put on a bit of weight, and that increases vulnerability to breathing problems at night. And menopause is not great for sleep at all, because you’re losing oestrogen and progesterone, and they help keep women’s sleep systems in terms of breathing at night quite open.”

Decreased melatonin

Ellis says melatonin, the hormone that helps regulate your sleep-wake cycle, decreases after puberty.

“That’s actually the beginning of the time our sleep system starts to degenerate,” he says. “So year-on-year, we start producing less melatonin naturally, and we start changing the architecture of our sleep.”

This means we start to lose some of the deep, slow-wave sleep needed for physical functioning from the age of about 25, he explains. “So by the time somebody’s reached their 60s, they’re a lot less structured with their internal sleep mechanisms than they were in their 20s. There’s a gradual decline.”

And Artis says:  “Sleep naturally changes as we age – particularly from our 50s onwards. While older adults still need around seven to nine hours of sleep per night, the structure and quality can shift quite noticeably.”

                                                             How to protect the quality of your sleep as you age (Alamy Stock Photo)

Shift in circadian rhythm

Several biological and lifestyle factors contribute to changes in the internal body clock of older people, says Artis. Hormonal shifts, including the reduced melatonin, play a role, she explains, and ageing is also associated with changes in brain function that affect sleep regulation

“Older adults often feel sleepy earlier in the evening and wake earlier in the morning,” she says. “This is sometimes referred to as a ‘phase advance’ in sleep timing.”

More easily disturbed

The decrease in deep, slow-wave sleep in older people means it’s easier for their lighter sleep to be disturbed, explains Artis.

“As we get older, we tend to spend less time in deep, restorative sleep and more time in lighter sleep stages,” she says. “This means we’re more easily disturbed by noise, light or physical discomfort, and many people also find they wake more frequently during the night and may struggle to get back to sleep.”

Lifestyle changes after retirement

(Alamy Stock Photo)

The rhythm of life tends to be a lot more structured for working people than retirees, Ellis points out. People who work will often have fairly regular times when they get up, eat, exercise, socialise, etc, whereas in retirement there’s less need for such structure, and this can affect sleep.

“Losing those patterns can make the system more vulnerable to being more flexible about getting bouts of sleep here and there, rather than in one big chunk,” he says.

And Artis adds: “Retired people may nap more during the day, be less physically active or spend less time exposed to natural daylight – all of which can influence sleep quality.”

Erratic sleep may not be good

Older people may think that as long as they get the right amount of sleep over a 24-hour period, it doesn’t matter when they get it. However, Ellis warns: “We’re starting to see research suggesting that keeping the same timing in sleep is actually as important, if not more important, than how much sleep we’re getting.

“We start to look at the regularity of sleep, as opposed to how much of it, if somebody is erratic. But unfortunately, most of the research has been done on younger adults or adolescents in this area, so we don’t fully understand yet whether the same thing applies with older adults and the regularity of their sleep.”

How is erratic sleep affecting you?

It’s natural for us to worry if our sleep has changed and/or we don’t think we’re getting enough of it. But Ellis stresses: “The first thing is to determine whether it’s causing you a problem. How do you feel in the daytime – is your sleep affecting your performance and what you need to achieve?

“If it is, then this is something you should be talking to your GP about.”

Ellis says these days a GP won’t automatically prescribe sleeping pills for a sleep problem – for insomnia, for example, he says cognitive behavioural therapy (CBT), which works on dysfunctional beliefs, attitudes and habits that may affect sleep, may be recommended.

And if someone’s sleep is being disturbed because of sleep apnoea (when breathing stops and starts while sleeping), continuous positive airway pressure (CPAP), which opens the airway at night, may be suggested, he says.

“There are lots of therapies out there, and they’re not all reliant on medication,” stresses Ellis. “It’s working out what the problem might be, and then tailoring that to the solution to try to maintain a better sleep health framework.”

And Artis points out: “While it’s common for sleep to feel lighter or more fragmented as we age, ongoing sleep difficulties shouldn’t be dismissed as simply part of getting older.

“Small adjustments to routine, light exposure and bedroom environment can make a significant difference. And importantly, support is available – good sleep remains vital for physical health, cognitive function and emotional wellbeing at every stage of life.”

https://www.irishnews.com/life/why-does-your-sleep-change-as-you-get-older-6PCVUUCVSJJHNMQ43SBZPCNH6A/

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