The secrets of sweating: how diet and lifestyle affect your body

28. July, 2025

Toitumine

Sweating is a natural and important process that helps the body maintain the right temperature. In hot weather or during physical exertion, the sweat glands in the skin are activated, covering the skin surface with a layer of sweat, which evaporates and cools the body. At rest, an adult secretes about 0.5 liters of sweat per day, but in a hot environment and with sustained physical exertion, sweating can increase to as much as 10–12 liters per day. Thus, sweating is a powerful tool for the body’s thermoregulation, without which we would not be able to survive long in the heat. Below, we will take a closer look at how sweating works physiologically, what the composition of sweat is, and how various dietary and lifestyle factors – from coffee and spicy foods to stress and hormonal changes – can affect both sweating and the body’s electrolyte balance.

Physiology of sweating

Sweating is controlled by our autonomic nervous system: when the body temperature rises, the hypothalamus in the brain signals the sweat glands to secrete fluid onto the surface of the skin. There are two types of sweat glands in human skin. Eccrine sweat glands are located all over the body and produce water-rich sweat that evaporates quickly. Apocrine sweat glands are located mainly in the armpits, groin area and elsewhere near hair follicles; they are activated by stress and hormonal signals and secrete thicker, protein-rich sweat. The main function of sweating is to prevent overheating – sweat that reaches the surface of the skin evaporates and thus removes excess body heat. The body does not spend any additional energy to secrete sweat (for example, sweating in a sauna does not burn calories, but simply loses fluid), and therefore the lost fluid must be drunk later. Overweight people often sweat more because the layer of fat prevents the body from cooling down and the body has to sweat more intensively to expel heat. Sweating is therefore not just an unpleasant phenomenon, but a vital mechanism that keeps our internal temperature under control and our skin moist and supple.

Sweat composition: water, salts and other substances

Human sweat consists of ~98–99% water, and the rest is made up of small amounts of various chemical compounds. The dissolved components of sweat include electrolytes – primarily sodium and chloride ions, or common salt – as well as smaller amounts of potassium, calcium and magnesium. In addition to electrolytes, sweat also contains other metabolites: urea and other nitrogen compounds (such as ammonia), lactic acid (lactate). Sweat that has just reached the skin is actually an odorless liquid, because it consists mainly of water and salt. An unpleasant odor develops later when bacteria living on the skin surface begin to break down the components of sweat – especially the protein- and lipid-rich sweat of the apocrine glands, which provides a favorable breeding ground for microbes. Therefore, it is important to take care of hygiene when sweating: wash your body and change clothes regularly to prevent bacteria from multiplying on the skin. In summary, sweat is mostly water with a pinch of salts and other compounds – it is this salty water on our skin that is the body’s natural air conditioning.

Caffeine and sweating

The coffee or other forms of caffeine that many people consume at the start of their day may be a mental stimulant, but they also stimulate the body’s physiology. Caffeine stimulates the sympathetic nervous system, speeding up metabolism and raising body temperature – as a result, sweating can be more intense. Studies have shown that caffeine administration increases the intensity of the sweating response: for example, it was observed that sweating began faster after caffeine consumption and sweat glands secreted more sweat during exercise compared to a placebo (4). Caffeine raises body temperature through thermogenesis and makes sweat glands more sensitive to nerve signals, which is why the body starts sweating earlier and more. Since caffeine also has a diuretic effect, it is important to pay attention to fluid intake when drinking a lot of coffee to avoid mild dehydration. People who suffer from excessive sweating are therefore advised to limit their consumption of coffee and other caffeinated beverages. In other words, while your morning coffee gives you energy, too much caffeine can heat up your body and make you sweat more than usual.

Spicy foods

Have you ever noticed that eating a hot chili makes your forehead glow and your nose run? Spicy foods—especially those that contain capsaicin (the burning component of chili peppers)—can trigger gustatory sweating, colloquially known as “food sweating.” Capsaicin binds to pain receptors in the mouth and tongue that normally respond to heat. As a result, spicy foods trick the body into thinking that the temperature has suddenly risen. The result is a chain of signals that control body temperature: blood vessels dilate, the heart rate increases, and the brain gives the command to activate the sweat glands at full capacity. The heat wave that sweeps through the body triggers sweating to quickly get rid of the imagined heat. This is a completely normal phenomenon, also called Frey syndrome, and it passes when the physical “disorder” subsides. When eating especially spicy foods, it’s worth remembering that sweating is a sign that the body is trying to cool itself down. If the spicy experience becomes too uncomfortable, drinking milk can provide relief – the milk protein casein binds capsaicin molecules and helps reduce the burning sensation. In short: spicy food makes your mouth “burn” and your skin flush because your body thinks it’s time to cool down.

Alcohol and sweating

Alcohol consumption can also lead to increased sweating. You may have noticed that after a few glasses of wine or a serious binge, your skin turns red and you can feel beads of sweat on your forehead. This is because alcohol affects the blood vessels and nervous system. Alcohol dilates the blood vessels in your skin (causing a warm flush) and speeds up your heart rate, which increases your body’s heat production and makes your skin warm. The body tries to get rid of this excess heat and triggers sweating (6). This effect is especially characteristic when you drink alcohol in the evening – at night, the body can break down alcohol, which is familiar to many. With moderate consumption in a cool environment, the effect may be modest, but in more sensitive people, even one drink can trigger a sweating reaction. In addition, alcohol (like caffeine) is a diuretic – it promotes the removal of fluid from the body through the kidneys. Therefore, alcohol is not a good way to replenish lost fluids, on the contrary: it can worsen dehydration. Medical recommendations emphasize that in order to avoid dehydration, you should limit drinks containing alcohol and caffeine, because they “take water out” of the body. For example, after heavy sweating (exercise, sauna), it is not the best idea to immediately quench your thirst with beer – you should drink water first, otherwise fluid loss may worsen. In summary, alcohol can be considered a two-way influence on sweating: in small quantities, it can relax blood vessels in some people, causing a warm feeling and slight sweating; in larger quantities, however, it triggers stress reactions (e.g. via the sympathetic nervous system), which also promote sweating, and in addition, alcohol takes water out of the body.

Stress, emotions and cold sweat

Stress sweat is a familiar phenomenon to many – a pounding heart, clammy palms and cold sweat on the forehead before an important performance or in an anxious situation. Emotional stress and anxiety activate the fight-or-flight response, which is controlled by the sympathetic nervous system. During this process, a large amount of adrenaline and other stress hormones are released into the bloodstream, which, among other things, activate the sweat glands. Unlike heat-induced sweating (which occurs all over the body), during a stressful situation, sweating occurs more heavily on the palms, soles, armpits and face, because the sweat glands in these areas respond particularly sensitively to impulses from the nervous system. Stress sweat is largely secreted by apocrine sweat glands, the product of which is different from normal “salty sweat”. Stress sweat is thicker and contains more proteins and lipids, which in themselves are odorless, but form a “feast” for bacteria on the skin – microbes break down these nutrients and create a strong characteristic sweat odor. This is why anxiety sweat tends to smell stronger than sweat from just hot weather. Studies have shown that stress sweat is made up of about 20% various organic substances (proteins, fats) and 80% water, while eccrine sweat is ~99% water. This also explains why antiperspirants and deodorants focus on the armpits – that’s where the components of stress sweat meet skin bacteria and the smell is created. There’s no escaping stress sweat in everyday life – exam fever, public speaking or even drinking strong coffee when you’re nervous can all make your heart beat faster and your skin sweat. The good news is that stress sweat can be combated with relaxation techniques and good hygiene and clothing choices (e.g. breathable materials, good antiperspirants). Above all, it’s worth remembering that cold sweat is your body’s signal that you’re stressed – so try to find time to rest and calm down so your body doesn’t have to work unnecessarily in an alarming state.

Hypoglycemia: when blood sugar drops too low

Surprisingly, low blood sugar, or hypoglycemia, can also cause sweating. When blood glucose levels drop below normal, the body reacts to it as if it were an emergency. The drop in blood sugar triggers the release of adrenaline as the body tries to mobilize stored sugar from the liver and raise blood sugar levels. Adrenaline – the same hormone released during stress – causes a whole range of symptoms: heart palpitations, shaking hands, anxiety, and very often a cold sweat. In fact, sweating is one of the key symptoms that diabetics and doctors use to identify hypoglycemia. Hypoglycemic sweat can be a frightening experience, but it is actually a sign that the body is working hard to ensure that the brain and vital organs get enough fuel.

Hyperthyroidism and excessive sweating

Hyperthyroidism is a condition in which the thyroid gland produces too many hormones (T3 and T4). These hormones regulate the rate of metabolism in all cells of the body, which is why hyperthyroidism causes the body to “overheat.” The metabolism goes into overdrive, the body temperature rises, and several symptoms appear: rapid heartbeat, trembling hands, weight loss – and also excessive sweating. People with hyperthyroidism often feel unwell in warm environments because their bodies produce excess heat. Heavy sweating and a constant feeling of heat are some of the characteristic signs of hyperthyroidism. The body tries to dissipate this heat by dilating blood vessels and sweating. According to statistics, excessive sweating (hyperhidrosis) is one of the complaints that brings people with hyperthyroidism to the doctor – along with a rapid pulse and weight loss, it often indicates a problem with the endocrine system (8). The good news is that if you treat your hyperthyroidism (with medication or other methods), your excessive sweating will also go away. In the meantime, staying in cooler conditions and drinking enough fluids and salts can help you feel better, as excessive sweating can lead to dehydration and weakness. If you are constantly hot, your skin is clammy, and you sweat a lot even when you are at rest, it is worth having your thyroid hormone levels checked by your family doctor – it is possible that the “secret” to your sweating lies in your thyroid gland.

Sweating and electrolyte balance

When we sweat heavily, we lose not only water, but also valuable electrolytes. Sweat is hypoosmolar (thinner) compared to blood plasma – this means that sweat contains relatively fewer salts than blood. However, if you sweat out liters of fluid, the loss of electrolytes (especially sodium and potassium) can become significant. Fortunately, the body has clever compensation mechanisms that try to balance the effects of sweating. Through the interaction of various mechanisms, the body tries to compensate for the loss of fluid and salt caused by sweating: we feel thirsty and drink, the kidneys produce less urine and maximally reabsorb salts to normalize blood volume.

It is important to understand that although the body is working hard, these measures alone may not always be enough. If the loss of fluid and electrolytes is very high (for example, during a long run, triathlon or sauna marathon), the person themselves need to consciously consume more fluids and salts, otherwise dehydration or a lack of salts may occur. Next, we will look at how to help the body compensate for the loss of fluid and minerals associated with sweating through diet and lifestyle.

Restoring fluid and electrolytes after sweating

When sweating heavily, recovery is just as important as cooling down. It is essential for the body to quickly replace lost fluids and salts to maintain normal cell function and blood volume. Here are some suggestions for how to mitigate the effects of sweating through diet and lifestyle:

Drink enough water: The easiest – but important – thing to do is to drink water according to your thirst and the amount of sweat you produce. Drink water as soon as possible after sweating – this will help prevent dehydration, which can lead to fatigue, headaches or muscle cramps. A good rule of thumb is to drink small amounts of water consistently until your urine turns light yellow (a sign of good hydration).
Restore electrolytes in the body: Sometimes just water is not enough, especially if you have lost a lot of salt. Isotonic sports drinks are suitable for replacing electrolytes (sodium, potassium, magnesium, etc.) lost through sweat. Studies confirm that during prolonged exertion, it is necessary to consume sodium in addition to water, otherwise excessive water consumption can lead to a salt balance disorder. The Be More mineral complex is also suitable as a practical recovery aid, which contains magnesium citrate, potassium bicarbonate, Himalayan salt and sodium bicarbonate – precisely the substances that the body loses through sweating. The product supports the normal functioning of the nervous system and muscles and is an excellent choice after intense physical exertion or being in a hot environment. We recommend mixing 1 teaspoon with a glass of water and consuming immediately after sweating.
Limit diuretics: After sweating a lot, avoid drinks that promote fluid loss. These include alcoholic beverages and drinks with too much caffeine (coffee, energy drinks).
Listen to your body: Everyone is different. Some sweat more salty (salt marks on clothes), others lose more potassium. Therefore, pay attention to how you feel. If you are very tired after sweating, have a headache or muscle cramps, the cause may be an electrolyte imbalance. In this case, pay special attention to your salt intake. Foods rich in magnesium (nuts, green leafy vegetables) and sources of potassium (bananas, potatoes) are also helpful. Your body will let you know quite quickly when the balance is restored – you will feel better and your strength will return.

In conclusion: sweating is a necessary process for cooling the body, but it is accompanied by a loss of water and electrolytes, which must be consciously compensated. The body activates the thirst sensation and hormone systems in the kidneys to maintain the balance of salts and water, but the person’s own contribution – drinking enough fluids and administering electrolytes if necessary – is just as important. It is worth remembering that sweating itself does not weaken the body, but careless recovery can (if fluid loss is not compensated). Therefore, keep the water and salt levels as a golden mean: avoid extreme thirst, but also avoid excessive drinking of only pure water during prolonged sweating. By doing this, you can enjoy exercise and hot summer weather without your body’s balance being shaken.

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