Why do I get awful-looking wrinkled skin when I stay in the bath or pool for some time? Why do my ears pop? Why do knuckles crack? This month, we answer some of the common questions about certain curious behaviour of our bodies.

Why Do I Have Wrinkly Fingers After Swimming?

You’ve been playing in the pool for almost an hour now, practising your breast stroke or doing underwater head-stands. Now it’s time to get out of the water; and horror is awaiting you! You have odd-looking wrinkled fingers. Your fingers have aged in an hour! How is it possible?

Don’t be afraid. You have not grown old overnight. It is completely normal for fingers (and sometimes toes) to wrinkle after spending lots of time in the water.

The outermost layer of our skin is covered with an invisible layer of its own special oil called sebum. Sebum protects and lubricates our skin. It also keeps water out and makes our skin a bit waterproof.

Can you imagine this? Without sebum, your skin will turn soggy every time you get caught in the rain, take a bath or wash your hands.

However, there is only a certain amount of sebum on your skin at a time. Once it is washed away, water can make its way into the outer layer of skin.

But why does that make my fingers wrinkle? Well, your fingers may look shrivelled. In fact, they are not really shrivelled, but waterlogged! Your skin swells in some places but not in others because of the extra water in your fingers. That’s what causes the wrinkles.

It’s not just playing in the pool for a long time that causes your fingers to wrinkle. Spending a long time in the bath, or any other activity that keeps your hands in water long enough will also give you wrinkly fingers.

You don’t have to worry though. The wrinkles will go away after some time and you’ll have more sebum on your skin in no time.

Why Do My Ears Pop?

If you’ve ever travelled on a plane, or taken a lift up or down a skyscraper, you might have experienced a weird or painful sensation in your ears. Your parents or fellow passengers advised you to swallow your saliva a few times. You did. And all of a sudden, you felt your ears have cleared up and the weird sensation or pain has gone away.

This feeling is known as the popping of the ears. But why do our ears pop?

The pressure of air in the atmosphere decreases as we go higher. When you travel up in a lift, the air pressure on your ears changes rapidly but the air pressure inside your ear drum remains the same as it was at ground level. So, as you go up, the pressure inside your ear drum becomes higher than the air pressure outside. Your ears then try to reduce the pressure inside. By doing so, the air inside presses against your ear drums, making you feel as if your ear drums are going to burst.

On the other hand, if you descend rapidly, such as when an airplane is touching down, the pressure of air outside the ear will be higher than that of the air inside. The opposite will happen. The air outside will press against your ear drums and you may feel pain.

There is a tube inside our ears that helps to maintain the pressure inside and outside our ear. It is called the Eustachian tube. This tube links the middle ear to the throat. A valve at the end of the tube admits or releases air to equalise the pressure on the inside and outside of the ear. However, in order to open this valve, we have to swallow. Our ears pop to remind us to swallow when we’re travelling up or down at a high speed.

Why do Knuckles “Crack”?

Lace your fingers together and bend them backwards. Or, press hard on a bent finger and you might hear a loud “c-r-a-c-k”. This sound is produced when bubbles in the fluid around your finger joints burst.

An adult human being has 206 bones. These bones are not too long otherwise we would not be able to bend or grasp things. Bones fit together at joints.

There are fixed and movable joints in our body. Most of the joints in our face are fixed except the bones of the lower jaw which are flexible. Movable joints such as those in our elbows, knees and ankles enable us to move around.

Bones at these joints are held firmly by tissues and ligaments. Inside each joint, there is a tiny sac that produces a thick fluid called the synovial fluid. This fluid lubricates our joint and helps it to move smoothly.

Whenever you stretch or bend your fingers, the bones of the joint move apart. As they do so, the tissues around it are stretched. This causes the volume of space around the tissues to increase. With an increase in the volume of space, the pressure in the synovial fluid drops, forming bubbles. When the joint is stretched far enough, the pressure drops so low that these bubbles burst, producing a cracking sound.

Cracking or popping your knuckles does not cause any harm or injury but scientists have seen signs of tissue damage and a decrease in grip strength in certain people such as professional sportspersons. This damage is caused by repeated stretching of the ligaments surrounding the joint.

Knuckle cracking does have some positive effects as well. Joints are more flexible immediately after. When joints are stretched, certain nerve endings are stimulated and the muscles surrounding the joint are relaxed.