The Science of Sweating, by Nithya K.Nambiar, 9-D

You are running as fast as possible with the finish line being in sight keeping you motivated to finish this race first. After a few seconds, you gather all the strength to travel with greater speed. Your legs are tired out but your mind wants to pick up the pace. Your breathing gets deeper as your heart pounds, your cheeks get red and sweat drips over the body at every little step you take. Now, WAIT RIGHT THERE! Speaking about sweat, what is this substance, why does it form the way it does and what is its purpose? Well, you’re lucky you clicked on this article because today we shall answer the question of why we sweat.

For starters, we need to study certain scenarios where sweat comes into action. Sweat is usually stimulated for a number of reasons like that of being sick, nervous reactions, responses of the body after consuming spicy foods. But to the most of us, exercise is a common way of activating sweat. In this case, the phenomenon of sweat happens as an answer to rapid movement, resonating with chemical reactions that trigger deep inside your cells. As you work out more, you tend to overuse especially muscles and tendons, increasing their demand for more energy. A process called cellular respiration consumes glucose that you gain from foods you eat and oxygen to create ATP (Adenosine triphosphate) molecules, which is referred to as the ‘energy currency of the cell’.

You must have learnt before that ATP is made mostly in structures called the mitochondria, the powerhouse of the cell. The cells then use this energy that has to be recharged from time-to-time as a useful mechanism to keep them strong, flexible and fit, much like a charger that you connect your phone to from keeping it away from dying! The process is truly very complex but basically the more our bodies undergo locomotion, the harder mitochondria works to provide energy to all our organs for functioning. However, everything comes at a cost and this brings us to sweat. As cells break down ATP into smaller parts for smoother consumption and efficiency, they release loads of heat. As heat rises, so does the temperature from sensors throughout and the receptors then detect the excess heat produced by your muscle cells, reporting it to the hypothalamus of the brain which regulates body temperature.

The hypothalamus sends signals or responses via the sympathetic nervous system to the sweat glands in our skin to activate. The concentration of the droplet like-substance that comes out as a result (sweat) can be seen focused on specific points like the palms of our hand, soles of our feet and even our forehead.

In depth we can say that, when the sweat glands of our body first get the response from the hypothalamus they get to work right away. The fluids that surround the cell in a coiled base structure contain huge amounts of both chloride and sodium. The cell pumps out the ions into a hollow tube through the sweat gland. Since it is saltier inside the tube than at the exterior, water comes in as osmosis occurs. The primary secretion builds up at the bottom or inner portion of the skin while water pressure pushes the liquid up along the straight duct. Before it seeps completely back into the skin after being pushed out, cells lining the tube will filter out as much of the salt they can. The water involved in sweating absorbs your body’s heat energy and slowly evaporates as it reaches the surface, thus evenly regulating the temperature of your body and cooling it down. This process is known as ‘evaporative cooling’ and researchers say that it was a very essential adaptation used by our ancestors too! This is how sweat is activated when our bodies undergo exercise.

But what about spicy foods? Does it go through the same process as it does during exercise? Why do some of us sweat harshly through our faces? Well, it is very similar to the first scenario as spices trigger the same nerves in the brain that activate the temperature receptors. Sweat is also characterized by the ‘fight or flight response’ that comes up during stressful situation like being interviewed for a job or writing a test. You may be confused why this happens although there isn’t any effect on temperature. It is because of adrenaline that supports muscle activity, causing blood vessels to widen and the body to become more alert. Sweat also enters when we are sick or having high fever because infections stimulate the hypothalamus to increase muscle activity which give out more heat energy and temperature, a protective way to no longer provide circumstances for any inhabitable pathogen to spread or withstand in the body.

When your fever ends or you finish the race you were running for, your glands and receptors sense a decrease in the temperature and the hypothalamus regulates your temperature back to normal. In some cases, after a heavy marathon the brain shares signals to the body to replenish the water that evaporated out as sweat. It is also composed with smaller quantities of salt and fat and natural bacteria covered on the skin mixed up causing a bad odor to it. So the next time you push yourself to that next goal you want to achieve, thank sweat that has been your body’s very own calibrator enabling you to go that extra mile ahead!