Sweat it Out

They say that horses sweat, men perspire, and ladies “glow”. Whichever way you look at it, this has been an incredibly hot and sweaty summer. The rainy season is almost upon us, but because we live in such a humid country, perspiration will always be part and parcel of living in the Philippines.

Purpose of sweat.
The body is like an engine that never stops running and like all engines, it produces heat. The more the muscles contract (like during exercise), the more heat is produced. Your body needs to be efficient at keeping you cool or you would rapidly overheat and collapse within 15 to 20 minutes. The reason this doesn’t happen is that your body has several ways of cooling you down.

The first is radiation. Heat radiates out of the skin and is absorbed by the environment if the surroundings are cooler than our body.

The second method is through conduction. This is the transfer of heat through direct contact. For example, if you go swimming in a cold mountain river, the water directly absorbs the heat of your body. The opposite is also true. If you swim in a hot spring, it will be your body that will absorb the heat.

Convection is the third method. Moving air helps to cool us down. Think of how refreshed you feel when the wind blows, when you manually fan yourself, or when you are under an electric fan.

Evaporation is the last method. Water from our blood absorbs the heat and rises to the surface of the skin via the sweat glands so that it can evaporate and create a cooling effect.

In hot weather, sweating is the primary method of staying cool. The other methods are inefficient because the environment is hotter than the body. In hot and dry conditions like the desert, sweat evaporates so fast that you don’t even notice it. However, if the air is humid (full of moisture), sweat cannot evaporate.

That’s why if you exercise in hot and humid conditions, sweat will roll and drip off your skin but you won’t feel any cooler. Since sweat cannot evaporate, the body needs the help of an air-conditioner (radiation), an electric fan or a good breeze (convection) to keep from overheating.

What is sweat made out of?
Sweat is composed mostly of water and trace substances like sodium chloride (salt), potassium, lactic acid and ammonia. Sodium and potassium are minerals that act as electrolytes to regulate blood pressure and water balance.

There are two types of sweat glands: apocrine and eccrine. The apocrine glands are actually scent glands that are located in the navel, armpits and groin. They produce a sticky kind of sweat that is odorless but is rich in fatty acids that bacteria present in the skin feed upon to produce the familiar B.O. smell.

The eccrine sweat glands, meanwhile, are found all over the body and produce a watery sweat that helps to regulate body temperature.

Everyone perspires differently.
Everyone has a different sweating pattern. How much you sweat is affected by genetics, gender, age, fitness level, and environment. Human beings can have between two to five million sweat glands. Women tend to sweat less and begin to sweat at higher temperatures compared to men.

It has been observed that people sweat less as they grow older and this means that elderly people cannot tolerate heat as well as younger people. However, declining fitness levels might be partially responsible because in laboratory experiments, when both old and young participants were of similar fitness levels, there was no significant difference in their sweating process.

Fit people sweat more “efficiently” by sweating sooner in the workout, in other words, at lower internal temperatures. However, this doesn’t mean that a fit person will always sweat more than an unfit person will. A sedentary person doing the same intensity workout as a fit person will get hot a lot faster and therefore will sweat more.

Overweight and obese people sweat more profusely than normal weight individuals because fat acts as an insulator that raises their core temperature.

The environment plays a big role in how much you are going to sweat. If you exercise in an air-conditioned room, you will not sweat as much because the cold dry air quickly evaporates your sweat. This doesn’t mean you are not burning many calories (caloric burn depends on the intensity and duration of the exercise). It simply means your body can easily deal with the heat being created by the exercise. Actually, exercising in a hot and humid room will just exhaust you faster and you will not burn as many calories as you would like to because you will stop working out sooner.

Invisible perspiration.
If you weigh yourself right before going to bed and weigh yourself again right after waking up (without going to the bathroom), you will find that you are lighter. No, you haven’t been sleepwalking to your gym. You have been losing water through transpiration or “invisible perspiration” as well as through exhaled respiration (in the form of minute water droplets). This overnight loss of water through your skin and breath explains why you are “thinner” with a flatter stomach when you wake up.

Dangerous practices.
Not drinking water before, during, and after exercise is a dangerous practice. It’s like taking your car out for a long drive without any water in your radiator. If you work out for more than 90 minutes in very hot and humid conditions, a sports drink is more appropriate than water to replace lost electrolytes.

Meanwhile, wearing plastic or rubber clothes while exercising is like wrapping your entire engine in plastic and then expecting your car to still run properly. You would never do these things to your car, so why do it to your body


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