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.

As bird flu continues to trouble several countries, health officials in the United States have reported the first known human case of the H5N5 subtype of avian influenza. The Washington State Department of Health announced on November 14, 2025, that the virus was found in a resident of Grays Harbor County.

The patient, an older adult with existing medical issues, is currently in the hospital. Authorities noted that the individual kept poultry at home that had contact with wild birds, which is believed to be the likely source of the infection, though the investigation is still underway. Since H5N5 is newly identified in humans, many are asking whether it differs from the earlier H5N1 strain.

What Is the H5N1 Strain?

H5N1 is a highly pathogenic form of avian influenza that mainly affects birds but can also infect mammals, including humans. It can lead to severe illness in people and has a high fatality rate, though it rarely spreads from one person to another, as per the World Health Organization. The virus has moved across continents in wild and farmed birds and has recently been found in dairy cattle and several other mammals.

What Is The New H5N5 Strain?

The “new” H5N1 strain refers to the 2.3.4.4b clade of highly pathogenic avian influenza (HPAI), which has caused a widespread animal outbreak since appearing in 2020. This version is a newer genetic branch of H5N1 and has swept through wild birds, poultry farms and an increasing range of mammals, including dairy herds in the United States. At present, the patient infected in the U.S. has been diagnosed with the newer H5N5 subtype.

How Is H5N5 Different From H5N1?

According to the CDC, both H5N5 and H5N1 fall under the avian influenza family, with the main distinction being the type of neuraminidase (N) protein on the virus surface. H5N5 contains the N5 protein, while H5N1 carries the N1 protein. Although this genetic change can influence viral features, their overall pattern of illness and symptoms is expected to be much the same, particularly in birds and livestock.

The genetic structure is the only difference, with H5N1 strain containing a subtype of influenza A with a segmented genome while the other has a new reassortant virus formed from several subtypes, possibly including H5N1, as per National Institute of Health.

Is A Vaccine Available For The H5N1 Bird Flu Strain?

Vaccines for bird flu do exist, but they are not intended for general public use and are not easily available for everyday protection. Some vaccines have been created and stored for possible deployment in people at higher risk, such as poultry workers and farm staff, and they are also used in animals like chickens to help manage outbreaks. The United States and several other countries have stockpiled H5N1-specific vaccines that could be rolled out if the threat to humans grows. A few nations, including Finland, are already offering them to certain high-risk groups. At the moment, there is no advice for the wider public to take a bird flu vaccine, as there is no sustained human-to-human spread and no mass-market human vaccine in use.

Flu season is here again and global health experts are getting worried about a strain that came up in June. The worry's cause is that the strain came up four months after the makeup of this year's flu shot.

This is the strain H3N2. The strain has caused outbreaks in Canada and in the UK, and health officials have warned about the early wave that is sending people to the hospitals.

As per Dr Wenqing Zhang, who is the head of the World Health Organization (WHO)'s Global Respiratory Threats Unit, "Since it emerged, it is rapidly spreading and predominating in some countries so far in the Northern Hemisphere."

The New Strain

The version of H3N2, which has been circulated worldwide this year "acquired 7 new mutations over the summer," said Antonia Ho, a consultant in infectious disease at Scotland's University of Glasgow. As per her media statement, this "means the virus is quite different to the H3N2 strain included in this year's vaccine".

The strain is now picking up in Canada, after it has been active in the UK, leading to flu cases being triple to what it was the same time last year. Furthermore, generally, H3N2 is thought to cause more illness, and this could be worse for older adults. In fact, Japan is also experiencing an early and harsh flu season. Japanese news outlet Nippon TV reported that as of November 4, flu cases in Tokyo has surged six times to the level it had seen last year. This data has been confirmed by the Japanese Ministry of Health, Labor, and Welfare. As per the media outlet, more than 2,300 day cares and schools were partially closed.

What Is Happening In The US?

H3N2, which is a strain of influenza have had some cases in the US, where people reported positive for flu. However, the Centers for Disease Control and Prevention (CDC) has not provided any detailed national report on flu since September 26, ever since the government shutdown happened.

What About This Year's Flu Shot? Will It Be Of any Use?

Every February, global health experts and vaccine manufacturers decide which flu strains should be included in the Northern Hemisphere’s fall vaccine, based on the strains circulating in the Southern Hemisphere. This year’s flu shot targets three strains, two influenza A types and one influenza B.

While the annual flu vaccine doesn’t always prevent infection, it significantly reduces the severity of illness. Last year, it was up to 55% effective in preventing hospitalizations among adults with the flu.

On Tuesday, U.K. health authorities reported early data showing that this year’s vaccine is up to 40% effective at preventing hospitalizations in adults.

Despite the variation in effectiveness, experts stress the importance of getting vaccinated. “Decades of data show that even when the match isn’t perfect, the flu shot continues to prevent hospitalizations, ICU admissions, and helps keep people out of the cemetery,” said Dr William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, in Nashville, Tennessee, as reported by NBC.

As of 7am today, Delhi's average AQI was registered at 446 as per aqi.in. However, the Early Warning System for Delhi, under the Ministry of Earth Sciences, Delhi's average AQI at 7am was registered at 341, slightly better, still close to 400. Dr Shivanshu Raj Goyal, a pulmonologist and Associate Director Pulmonary Medicine at MAX Healthcare in Gurugram and Delhi, in an Instagram video said that breathing this toxic air is equivalent to smoking 20 cigarettes in a day.

No One In Delhi Is A Non Smoker

The doctor starts his video with a rather strong statement, "At present, no one in Delhi-NCR is a non-smoker."

"With the AQI of around 400, if I break down the facts, with every 20 of an AQI of PM2.5, is equivalent to smoking a cigarette. So at the AQI of around 400, you are smoking easily 20 cigarettes a day. That is for everyone, each one of us, even a small change. So imagine the amount of damage that this AQI must be causing to your lungs," he says.

The doctor also states that on an average, a person breathes around 20,000 times in a day, so it means we are inhaling the toxic air at least 20,000 times a day.

As per Action on Smoking and Health (ASH), a cigarette contains nicotine, and tar, which is composed of chemicals like benzene, benzopyrene, and the gas includes carbon monoxide, ammonia, dimethyl nitrosamine, cadmium, formaldehyde, hydrogen cyanide and acrolein. Some of these marked irritant properties are also carcinogen, meaning, it can cause cancer.

Whereas Air Pollution contains pollutants like particulate matter PM 10 and PM 2.5, ozone, nitrogen dioxide, carbon monoxide, cadmium and sulfur dioxide. Air pollution, which is often a byproduct of combustion or released from vehicle exhaust also contain formaldehyde, benzopyrene, and benzene. As per the World Health Organization (WHO), the pollutants contain carcinogens, and the outdoor air pollution is in fact classified as Group 1 carcinogen.

Common Carcinogen In A Cigarette And Air Pollutants

Carbon Monoxide: a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air.

Benzene: a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline.

Cadmium: a soft, silvery-white metal (atomic number 48) that is toxic and naturally found in the environment, but human activities have increased its levels. It is used in products like batteries, pigments, and coatings, and exposure can occur through tobacco smoke, contaminated food, and occupational inhalation. Cadmium is a known human carcinogen that can damage the kidneys and bones.

Formaldehyde: a colorless, flammable gas with a strong odor, whose exposure could cause cancer.

Benzopyrene: a group of organic compounds known as polycyclic aromatic hydrocarbons. It is a colorless crystalline solid found in sources like cigarette smoke, coal tar and is a known carcinogen that can cause cancer and other health problems like skin rashes and bronchitis, and exposure requires medical attention for any symptoms.

So, What Can Be Done To Protect Yourself Against These Carcinogen?

Dr Shivanshu Raj Goyal points out that these carcinogens could lead to long term lung and heart damage, as well ass cause chronic cough, breathlessness, asthma, and COPD. However, there are ways to protect yourself:

• Avoid outdoor activities during peak pollution hours
• Use N95 masks when stepping out
• Keep air purifiers on indoors
• Stay hydrated and include antioxidant-rich foods
• Visit a pulmonologist if you experience persistent breathing issues