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.

In a medical first, surgeons in China have successfully transplanted a gene-edited pig liver into a living human to temporarily support his failing liver. The procedure showed that a pig liver can function inside the human body for several weeks and act as a “bridge” for patients who have no other treatment options.

The patient was a 71-year-old man with severe hepatitis B–related liver cirrhosis and a large liver cancer tumor. His condition made traditional surgery or a human liver transplant impossible. With no donor organs available and his health rapidly worsening, doctors decided to try the experimental pig liver transplant under compassionate use.

How the Pig Liver Was Engineered

The donor organ came from a specially bred Diannan miniature pig. Scientists had made 10 specific genetic changes to the animal so its liver would be more compatible with the human body.

These changes included:

• Removing pig genes that usually trigger strong immune rejection
• Adding seven human genes to help the liver work smoothly with human blood, immunity and clotting systems

Once the liver was connected to the patient’s blood supply, it began working immediately. It produced bile, supported metabolism, made important proteins like albumin and helped with blood clotting. Early tests showed stable liver and kidney function, and there were no signs of sudden or severe rejection, which is usually the biggest challenge in pig-to-human organ transplants.

A Serious Complication Emerges

But the case also revealed a major challenge for future xenotransplants. After about a month, the patient developed a condition called xenotransplantation-associated thrombotic microangiopathy (xTMA).

This complication caused:

• Breakdown of red blood cells
• A drop in platelets
• Activation of the complement system (part of the immune response)
• Small blood clots forming in blood vessels

Doctors tried multiple treatments, including blood thinners, a complement-blocking drug (eculizumab) and plasma exchange. However, the condition continued to worsen.

On day 38, the medical team decided to remove the pig liver to protect the patient. Fortunately, during this period, the patient’s remaining left portion of his own liver had grown and was able to take over enough liver function. After the pig liver was removed, the signs of xTMA gradually resolved.

The patient later developed complications unrelated to the xenotransplant — mainly repeated bleeding in his digestive tract due to his pre-existing liver condition — and he died on postoperative day 171.

What This Means for the Future

Researchers conclude that this groundbreaking case proves pig-to-human liver transplantation is technically possible and can meaningfully support patients for weeks. This offers hope for people with acute liver failure or advanced liver cancer who have no donor organs available.

However, major barriers remain. The biggest challenges highlighted include:

• xTMA
• Blood clotting incompatibilities
• Overactivation of the immune system
• The need for better gene-editing strategies

Scientists say more work is needed before such transplants can become routine. But this case sets an important foundation for future clinical trials and brings the medical world a step closer to using animal organs to save human lives.

Screening for all men is "likely to cause more harm than good", says the UK National Committee. This recommendation is based on a clinical trial called Transform, which is now filling gaps in the evidence on how screening could be safely rolled out to other groups.

As of now, as per the recommendation, men who are between the ages of 45 and 61 should be screened every two years, if they have specific genetic mutations called BRCA variants.

The UK National Screening Committee recommends:

• No screening for black men due to "uncertainties" around the impact due to a lack of clinical trials in black men
• No screening based on family history

Why Is The New Recommendation Asking People To Not Get Screened For Prostrate Cancer?

As per the clinical study and the Cancer Research UK, of the 1000 men who get screened between the age of 50 to 60 for PSA test or the prostate-specific antigen test, around 100 have a positive PSA test. Of them, 34 have a positive MRI and receive a biopsy. Then only 28 are diagnosed with prostrate cancer. Of those 28, 10 are offered active surveillance, 13 are offered surgery or radiotherapy, and 4 need surgery or radiotherapy, while 1 need any other treatment.

However, the Cancer Research UK notes that while 1000 men are screening, and 28 diagnosed, only 2 lives could be saved, with 20 being over diagnosed, this means they have a slow-growing tumor that does not need treating, and of them 12 men will receive treatments that do not benefit them, rather harms them. These harms come in forms like being unable to control your bladder, or maintain an erection.

Is Prostrate Cancer Screening Recommendation Fit For All?

While experts say it is, patients are disappointed. Sir Chris Hoy, a terminal prostrate cancer patient says he was "disappointed and saddened" by the new recommendations as BBC reports.

However, Prof Freddie Hamdy, who is a urological surgeon in Oxford tells BBC: "The diagnosis of prostrate cancer in a healthy man is hugely disruptive event, with potential to affect quality of life, very significantly, for many years."

"It cannot be done lightly, men need to be really well counselled and informed before the 'snowball' starts. Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time," he said.

The screening committee’s decision is not final. It marks the beginning of a three-month public consultation period, after which the committee will reconvene and present its final recommendations to ministers in England, Wales, Scotland, and Northern Ireland. Each nation will then make its own decision on prostate screening.

England’s Health Secretary Wes Streeting said he supports screening “if backed by evidence” and promised to review the data “thoroughly” ahead of the final guidance expected in March.

Reactions to the draft recommendations have been sharply divided. Cancer Research UK welcomed the consideration of screening for men with faulty BRCA genes and agreed that, for most men, screening could currently do more harm than good.

But others strongly disagreed. Sir Chris Hoy said he was “extremely disappointed and saddened,” calling the BRCA-specific recommendation “a very small step forward” that falls short. Sharing his own experience, he emphasised that “early screening and diagnosis saves lives.”

Prostate Cancer UK CEO Laura Kerby also expressed being “deeply disappointed,” saying the decision will “come as a blow” to tens of thousands of men.

Prostate Cancer Research criticized the move as “a serious error that ignores modern evidence,” calling it a missed opportunity for Black men and those with a family history.

Many people struggle to fall asleep because their minds race with worries about the next day or even old memories. To stop this mental chatter, some try complicated breathing exercises or relaxation hacks. However, a simple neuroscience trick involving temperature might help you drift off instantly.

Neuroscientist Kyle Cox suggests that you can fall asleep in seconds simply by placing something cold on your forehead when you go to bed. He explains that this method has been backed by sleep clinics and can be highly effective.

Sleep Hack That Could Help You Sleep Quicker

Researchers have learned that the temperature right on your forehead controls whether your brain stays active or decides to rest.

When the front part of your brain, called the frontal lobe, gets cooled down by even a little bit, just one degree, it automatically tells your body to start producing the chemicals needed for sleep.

The cold also quickly slows down all that busy mental chatter because the part of your brain that handles thinking (the prefrontal cortex) literally cannot work as hard when it is being cooled down.

A 2018 study published in the Sleep Journal also found similar results through a device that that cooled the forehead temperature as a treatment for insomnia. The device improved things like the time it took to fall asleep compared to the patient's own baseline sleep and the time it took to enter different stages of light and deep sleep (NREM Stages 1 and 2).

The two-night treatment helped patients fall asleep faster according to most PSG measurements and was safe. The researchers recommend more studies to see if this treatment works for the longer-term management of insomnia.

General Tips for Treating Insomnia

If you struggle with sleep, the NHS (National Health Service) says that often the best cure is to change your daily sleep habits. If you stick to a healthier routine, your insomnia usually gets much better over time.

Keep a Schedule

Go to bed and set your alarm to wake up at the exact same time every day, even on weekends. This helps set your body's internal clock.

Wind Down

Start relaxing at least one hour before you plan to sleep. This could mean taking a warm bath, listening to calm music, or reading a physical book.

Optimize Your Room

Make your bedroom a perfect place for sleeping. It should be as dark and quiet as possible. Use heavy curtains, blinds, or even an eye mask and earplugs if needed.

Get Moving

Exercise is great for sleep, but do it regularly during the day, not right before bed.

Be Comfortable

Check that your mattress, pillows, and blankets are supportive and cozy so you can easily relax once you lie down.

Things You Should Avoid For Better Sleep

To sleep better, avoid things that keep you awake. Stop smoking, drinking caffeine or alcohol six hours before bed. Do not eat a large meal or exercise intensely late at night. Avoid screens right before bed, limit daytime naps, and always stick to your regular morning wake-up time.