We have all seen movies where right before the hero starts fighting, he cracks his knuckles and makes it look like the coolest thing in the world! But then our parents told us that you should not crack your knuckles because that weakens your grip and hand strength. But is that true? While many people do say that they experience a small loss in strength immediately after they crack their knuckles, but are their long-term effects to it? And what is the sound actually coming from?

The reason why people crack their fingers is because the evident and sharp crack noise causes a sense of relief. Many people also do it when they have done an activity that required them to work with their hands a lot like typing or sewing, giving themselves a sense of satisfaction, similar to stretching after doing hard work. That "crack" sound can make some people cringe, while others find it strangely satisfying. Cracking your knuckles is a pretty common habit, but there are a lot of misunderstandings about it. Some people do it without even thinking, others can't stand the noise, and some can't crack their knuckles at all. You might have been told as a kid that it causes arthritis or makes your fingers swell up. But those are just old wives' tales. There's a real science behind this habit, and it's more interesting than you may think.

Why Do Knuckles Make That Popping Sound?

The "crack" isn't actually bones breaking or anything bad happening to your joints. It's a normal thing called "crepitus." This just means harmless popping, snapping, or grinding sounds that come from your joints. The main reason you hear this sound is because of gas bubbles in the fluid that cushions your joints. This fluid is called synovial fluid. When you move or stretch, these tiny bubbles form and then pop, making the sound. It's totally normal and doesn't hurt you. Sometimes, especially in bigger joints like your knees, shoulders, or ankles, the sound can also happen when the stretchy tissues that connect your bones (ligaments and tendons) move slightly and then snap back into place.

After you crack your knuckles, you can't usually do it again right away. You have to wait a bit. That's because the gas bubbles in your joint fluid have already popped, and it takes a little while for them to build up again. While cracking your knuckles doesn't give you arthritis, doing it too much might cause some problems. Doctors say that cracking them too often could make your joints a little wobbly and might even make your grip weaker. Also, if the stretchy tissues in your joints keep snapping over your bones, they can get irritated and sore.

When Joint Popping Might Mean Something More

Sometimes, a pop in your joint is just like cracking your knuckles, nothing to worry about. But other times, it can be a sign of something else. As we get older, the cushiony stuff in our joints, called cartilage, can start to wear down. This cartilage helps your bones move smoothly. When it gets thin or uneven, the bones can rub together, and that can make a grinding or popping sound. This is different from the pop you get from gas bubbles. If this grinding sound happens along with pain, it could be a sign of osteoarthritis. This is a type of joint problem that's more common in older people, but younger people can get it too, especially after a joint injury. If your joints hurt, especially in the morning or after you've been sitting still for a while, feel wobbly, or are hard to move, it's a good idea to see a doctor.

An international team of researchers has developed an artificial intelligence (AI)-based tool that can significantly improve care for glaucoma -- a leading cause of irreversible blindness worldwide, according to a study published in The Lancet Primary Care journal today.

Researchers led by those from the University of Lisbon in Portugal found that the AI-based screening tool halved the number of unnecessary referrals for glaucoma.

The study, released during the Glaucoma Awareness Week, also showed an accuracy level at par with human eye doctors.

"The high accuracy at excluding people without glaucoma is especially important, as false alarms can lead to unnecessary hospital visits, patient anxiety, and added strain on healthcare services," the researchers said.

According to the researchers, AI-based screening could:

• support earlier detection,
• reduce unnecessary specialist referrals,
• prevent avoidable vision loss,
• can be integrated into routine primary care in a cost-effective way

Key Findings

The study was carried out at a single screening center in Lisbon, Portugal, in 2023.

The experts screened 671 adults aged 55-65 for glaucoma via the AI tool, analyzing images of the eyes. The images were then independently graded by six glaucoma experts.

The AI-tool:

• referred 66 people (9.8 percent) vs 118 referrals (18.0 percent) by the eye doctors,
• diagnosed glaucoma in 40 participants (6.4 percent).
• It correctly identified 78 percent of people who truly had glaucoma, vs 75 percent identified by the eye doctors
• Correctly ruled out the disease in 95 percent of people, vs 91 percent by eye doctors

While modelling studies suggest that screening could substantially reduce glaucoma-related visual impairment and blindness, barriers include the need for specialised diagnostic equipment and trained personnel, particularly in low- and middle-income countries, and the intrinsically low positive predictive value of screening tests.

In such a scenario, the new study showed that "AI may provide a more viable option than population-wide screening", which may seem impractical.

What Is Glaucoma?

Glaucoma is a chronic disease that affects an estimated 80 million individuals globally, according to the World Glaucoma Association.

It is a progressive, degenerative disorder of the optic nerve that produces characteristic visual field damage.

The disease stems from a long asymptomatic phase, resulting in substantial underdiagnosis and delayed treatment.

Even in high-income countries, up to 50 percent of individuals with glaucoma remain undiagnosed, frequently presenting moderate to advanced disease at first detection.

By the year 2040, it is estimated that there will be 22 million individuals worldwide who are blind from glaucoma.

When to see a doctor for glaucoma:

• Vision suddenly gets blurry
• Severe eye pain
• Headache
• Nausea
• Vomiting
• Rainbow-colored rings or halos around lights

In adults, long periods of sleep deprivation has been linked to problems such as weakened immunity, weight gain, depression, and an increased risk of dementia. However, scientists are now paying closer attention to how sleep affects the brain much earlier in life.

However, a new University of North Carolina School of Medicine study suggests that disrupted sleep during early childhood may interfere with key stages of brain development and asl well as increase the risk of developing autism.

Why Sleep Matters For The Developing Brain

Sleep plays a crucial role in helping these synapses form and strengthen. During sleep, the brain organizes and stabilizes these neural connections, shaping the foundation for future brain function. If sleep is repeatedly disrupted during this delicate stage of development, the process may be affected.

Frequent waking or sleep disturbances could interfere with how these neural connections are formed, potentially influencing behavior and cognitive abilities later in life.

The Link Between Sleep And Autism

“The unique effects of sleep loss during development are largely unexplored,” Diering said. “Our data show that babies and children are more vulnerable to the negative effects of sleep disruption. We also found that sleep loss during this crucial period of time can negatively interact with underlying genetic risk for autism spectrum disorder.”

Sleep problems are already known to be common in people with autism. In fact, sleep disruption has been reported in more than 80 percent of individuals with autism spectrum disorder. However, researchers have long debated whether these sleep issues are a cause of the disorder or a consequence of it. Understanding how sleep interacts with brain development could help scientists detect autism earlier and potentially develop new treatment strategies.

Studying Sleep Disruption In Early Life

In earlier work conducted in 2022, researchers examined how sleep disruption during early life might interact with genetic factors linked to autism. Using mouse models, they disrupted sleep during the third week of life, a developmental stage roughly comparable to ages one to two in humans.

The study found that sleep disruption during this period produced long lasting behavioral changes. Male mice that were genetically vulnerable to autism showed deficits in social behavior later in life. These results suggested that sleep disruption during critical stages of development may interact with genetic risk factors in ways that shape long term behavior.

Younger Brains Respond Differently To Sleep Loss

To investigate further, researchers studied how developing and adult mice respond differently to sleep deprivation.

Using specially designed housing systems equipped with sensitive sensors, scientists tracked the animals’ breathing and movement. This allowed them to determine when the mice were awake and when they were asleep.

The researchers observed that adult mice were able to compensate for lost sleep. After experiencing sleep deprivation, the adults increased their sleep later during their normal active period. This process, known as sleep rebound, allowed them to recover some of the lost rest.

Younger mice behaved very differently. They showed no sleep rebound at all, meaning they did not compensate for the sleep they had lost. This finding suggests that younger brains may be far more vulnerable to the effects of sleep disruption.

The consequences were also visible in cognitive performance. Sleep deprived young mice performed poorly on learning and memory tasks, while adult mice were significantly more resilient after losing sleep.

Changes At The Level Of Brain Synapses

The results showed that sleep deprivation in young mice significantly altered the formation of synapses. These changes were not seen in adult mice. “This now provides one of the largest and most comprehensive datasets to examine the molecular effects of sleep loss across the lifespan,” Diering said.

Potential Future Treatments

“Development is not something that one can go back and do again,” Diering said. “Sleep is important for the entire life and especially during development. Understanding what we know now will place greater emphasis on understanding sleep issues in ASD and could lead to an important therapeutic avenue to treat ASD and other developmental conditions.”

The findings highlight an important message for parents and caregivers. During early childhood, healthy sleep patterns may play a critical role in shaping the brain for years to come.

Using amphetamines, cocaine and cannabis can significantly increase your risk of having a brain stroke particularly among younger adults, according to a new University of Cambridge analysis

The findings highlight how recreational drug use may contribute to a preventable health risk, especially among people under the age of 55.

Megan Ritson, a stroke genetics researcher at the University of Cambridge and lead author said the results provide strong evidence linking certain drugs to stroke risk.

“These findings provide compelling evidence that drugs like cocaine, amphetamines, and cannabis are causal risk factors for stroke,” Ritson noted.

A stroke occurs when blood flow to part of the brain is interrupted. This can happen when a blood vessel becomes blocked by a clot, known as an ischemic stroke, or when a blood vessel bursts and causes bleeding in the brain, known as a hemorrhagic stroke. Both types can lead to serious brain damage and can be life threatening.

Amphetamines Associated With The Highest Risk

When researchers combined data from eight previous studies, they found that recreational amphetamine use was associated with more than double the risk of stroke across all adult age groups. For individuals under the age of 55, the increase was even greater. In this group, amphetamine use was linked to nearly triple the risk of stroke compared with people who do not use the drug.

Across all age groups, the analysis found that amphetamine use increased the risk of ischemic stroke by 137 percent and hemorrhagic stroke by 183 percent. These figures reflect relative risk, meaning the probability of stroke is higher among users compared with non users.

Cocaine Shows A Similar Pattern

The analysis showed that cocaine use nearly doubled the risk of stroke of any kind and more than doubled the risk of hemorrhagic stroke. Additional genetic investigations were conducted alongside the main analysis to better understand whether the relationship might be causal rather than simply linked to other lifestyle factors.

Eric Harshfield, a genetic epidemiologist at the University of Cambridge, said the findings suggest the drugs themselves may play a direct role. “Our analysis suggests that it is these drugs themselves that increase the risk of stroke, not just other lifestyle factors among users,” Harshfield said.

Cannabis Linked To Smaller But Significant Risk

Among people under the age of 55, cannabis use was linked to a 14 percent increase in stroke risk. Although the increase is lower than that associated with stimulant drugs, researchers say it remains important because cannabis is widely used.

Opioids Showed No Clear Association

A Preventable Health Risk

The researchers also note that many of the studies included in the analysis relied on participants reporting their own drug use. Because of this, other lifestyle factors could potentially influence the results. Further research will be needed to better understand the biological mechanisms involved and how different patterns of drug use may affect stroke risk. Still, scientists say the evidence now available provides an important foundation for future public health strategies.

“These findings give us stronger evidence to guide future research and public health strategies,” Ritson said.