Sweat and health: this is how they are related

Sweat, in addition to regulating our body temperature, can contain biomarkers that provide information about our health.

August in Spain is synonymous with unbearable heat (with the permission of the northern communities, which usually enjoy temperatures more compatible with human life). When the thermometers flirt with 40ºC, going outside becomes a truly impossible mission, one that would put Ethan Hunt himself in trouble. At noon, the cities are deserted, the silence only interrupted by the engine of a bus and the song of cicadas in the green areas. The few pedestrians who must venture outside do so covered in sunscreen from head to toe and move from one shade to another to avoid the strong rays of the sun. Sweat becomes our inseparable companion until autumn begins and, with it, the cool days return.

Being sweaty is not a very pleasant feeling. Feeling your skin constantly wet, even sticky, can be quite annoying. Not to mention the odor that accompanies it at times, which can turn trips on public transport at rush hour into an experience to forget. However, Sweat is a necessary evil in those moments of extreme heat. In addition, it may contain important information about our health.

Sweat glands in health and disease

We owe the fact that we can sweat to the sweat glands, distributed throughout our skin. These glands are activated when our body temperature rises. Its mission is to reduce it so that it falls within normal parameters, since an excessively high temperature is not good for the body. To do this, they produce and secrete sweat to the outside, which It is nothing more than water with some dissolved substances, including minerals such as sodium and potassium or organic substances such as urea and lactic acid.

When sweat evaporates on our skin, it cools us, thereby lowering body temperature. The main areas of sweating are the armpits, feet and hands, although our entire skin can participate in the process on specific occasions, for example, when it is very hot outside or when exercising intensely.

If the sweat glands do not function, we are faced with a disorder called anhidrosis. People who suffer from it have problems regulating their body temperature, as they do not sweat as much as they should or even at all. Therefore, they tolerate high outdoor temperatures very poorly, which causes fatigue and discomfort. This makes them more susceptible to heat stroke. Anhidrosis can be due to different causes, from genetic diseases to skin lesions, to side effects of some drugs.

On the other hand, some people may have overworking sweat glands. So we talk about hyperhidrosis. This excessive sweating is usually related to stressful situations., which stimulate the sweat glands, although it can also be due to the side effects of some drugs. Hyperhidrosis is less dangerous than anhidrosis, although it can cause embarrassment to those who suffer from it, as well as increase the risk of skin infections.

Sweating towards the future

As if the importance of sweat in human life were not enough, we could still get more juice out of it. Some of the substances that make up sweat can be very interesting for analyzing a person's health. This is what we call biomarkers, compounds whose levels indicate the presence of a disease, its state and its response to treatment, among other factors. 

Normally, we use blood to analyze different biomarkers, but blood tests can be quite uncomfortable. Sweat samples, on the other hand, can be taken non-invasively., making things easier for the patient. Of course, we cannot banish blood tests yet, because the information that sweat provides us is smaller, but it can be useful for some disorders.

People with hyponatremia, for example, might benefit from sweat analysis. Hyponatremia is a disorder related to abnormally low sodium levels in the blood. This is a serious problem, since sodium is key to controlling the amount of water that enters and leaves cells. If its levels are low, excess water enters the cells, causing them to swell and make us feel unwell, possibly even falling into a coma. 

Since sweat contains, among other compounds, sodium, some researchers have thought that this fluid could be more useful than blood for measuring it. With this in mind, sensors are being developed capable of analyzing the amount of sodium in sweat in real time. In addition to measuring hyponatremia, these sensors could be useful for monitoring other diseases such as cystic fibrosis.

Some researchers take this idea of ​​sensors to analyze sweat further to the point of proposing 'smart clothes'. That is to say, they intend for our clothing to also join the bandwagon of smartphones, smart televisions, smart watches and a long etcetera. To do this, they propose integrate this type of sweat sensors between the fibers that make up the fabrics of our t-shirts. Since the shirt is in direct contact with the skin at all times, we could have a real-time analysis of the different biomarkers contained in the sweat, which would provide us with direct information about our condition.

While we wait for smart clothes to arrive, we will have to settle for what we have until now and change our relationship with sweat, that it is time for us to give it the attention it deserves.

Source and Photography: Heraldo de Aragón