Why Sweating Is Good For You
lthough it gets a bad reputation, sweating is a normal bodily function necessary for our survival. It is responsible for thermoregulation in humans, which maintains our state of homeostasis by reducing our temperature through a process called evaporative cooling. Effectively our body covers itself in water which evaporates due to increased body heat, removing the excess heat from our bodies and allowing our cells to function normally. This process occurs when we are surrounded by hot temperatures or our muscles are being used extensively.
Humans are extremely rare animals when it comes to perspiration. We are among a select group of perhaps 40 animals that produce enough sweat across our body to ensure thermoregulation without the need for shelter (shade) or immersion (swimming, mud baths). The average human adult is capable of sweating anywhere from 2-4 litres per hour, meaning that excessive sweating requires that we rehydrate more frequently. If you are accustomed to regular fitness programs or live in a hot climate, you know how thirsty you get when you go outside or perform a particularly intense workout.
There are two situations that cause sweat: physical strain and mental stress.
When we exercise, our energy pathways force our muscle cells to give up ATP as an energy source for immediate strength and muscular endurance. This gives us the energy to power through a workout, but it also causes excessive heat to form inside the body. This process is roughly similar to the one which goes on inside a car engine after you turn it on. The engine block will heat up rapidly unless it is cooled by a liquid coolant. Instead of automotive coolant, our body produces sweat which draws the heat out of the body through evaporation. You have felt this process in a more direct form if you have ever got out of a pool on a windy day and felt chilled. The wind pulls the water – and your body heat – away from you.
Unlike sweat caused by physical strain which covers the entire body, sweat caused by mental stress tends to be localized to specific areas of the body. These areas tend to be enclosed places such as inner joint connections and the palms. This enclosed environment paired with bacterial preference for warm, wet spawning grounds leads to greater bacterial growth in these areas with a corresponding smell (body odor). This means that people can literally smell your nervousness, stress and anxiety although it is generally taken as a sign of poor hygiene.
The Science Behind Beneficial Sweating
Humanity has a history of using sweating as a means of purifying the body. The Romans built public baths with hot water designed to increase the core temperature of bathers for relaxation and to “balance the humours” – a series of bodily substances including blood and phlegm thought in ancient times to give us our personality. Today we use the same process in saunas and hot tubs, although for more scientific reasons.
Primarily made up of water, sweat contains soluble materials (primarily sodium, lactate and urea) which are poisonous for our body if they are too concentrated. High sodium is a problem affecting 75% of Westerners, primarily due to poor diet and a lack of exercise. The average person requires 1.2-1.5 grams of sodium every day for normal performance but consumes approximately 3.4 grams a day. As a result, Westerners regularly feel dehydrated – a problem exacerbated by high levels of caffeine and alcohol consumption which act as diuretics. A liter of sweat contains approximately 1 gram of sodium, so a sufficiently long workout (1 hour) of significant intensity would produce 2 liters of sweat and reduce your sodium to acceptable levels.
Lactate is the substance that builds up in our muscles during exercise and causes fatigue and muscle pain. Sweating will (counter-intuitively) reduce the soreness after a workout. Urea is the primary ingredient in our urine and is a waste product of the human metabolic system.
That’s right, you sweat pee. On the plus side, you are also removing toxins from your body.
While these soluble materials are nowhere near the concentrations found in the substances that bear their names, consistent sweating due to physical strain is a method of lightening the load on the brain in terms of maintaining homeostasis. It will reduce the amount of toxins in your body and will help to remove sodium from your system.
A physically fit individual will sweat more easily and more intensely than someone who is not in shape. This is because the body has acclimatized itself to regular physical strain and is always prepared to cool down the body’s core temperature. However, a larger person (regardless of fitness level) will sweat more than a smaller person because their body produces more body heat during exertion.
Sweating is beneficial to workouts because it tells us when we are exercising our muscles sufficiently. If you have done a workout without sweating significantly, you have not exercised your muscles hard enough and you have effectively wasted your time. After 30 minutes to an hour of exercise, you should feel thirsty enough to drink at least 500 mL of liquids. Since an hour of moderate physical strain causes the average person to sweat approximately 2 L worth of water, your body should be craving liquids as a means of balancing its internal chemistry.