When we think of a sauna, most of us picture warmth, relaxation, and a sense of well-being. What we think about less often is that we also lose something during sauna bathing. Primarily water, along with certain minerals and electrolytes. Sweating is the body's way of cooling itself down, and the more intensely we sweat, the more fluid we lose. But that doesn't mean we need to replenish dozens of minerals with special drinks or supplements after every sauna session. Quite the opposite. Once we understand what we actually lose through sweating and in what amounts, we realize that recovery after sauna bathing can be much simpler. It's about understanding what the body needs and knowing when plain water is enough, when mineral water makes sense, and when it's worth paying closer attention to electrolytes. ###What Do We Actually Lose Through Sweating? Sweat contains primarily sodium and chloride, along with smaller amounts of potassium, magnesium, and other minerals. When it comes to sauna bathing, the key point is that we lose water and a certain amount of electrolytes through sweating. However, the proportions vary from person to person. Some people sweat more, others less. Some have saltier sweat than others. These differences are influenced by factors such as heat adaptation, sweating intensity, and the conditions in which we use the sauna. Regular exposure to heat also plays an important role. Over time, the body adapts and becomes more efficient at conserving sodium. In other words, heat adaptation doesn't necessarily teach the body to sweat less. It teaches the body to manage what it loses through sweat more efficiently. ###Sodium Is the Most Important Mineral Lost Through Sweating If there is one mineral worth paying particular attention to during heavy sweating, it's sodium. It helps maintain the body's fluid balance and is essential for the proper functioning of the nervous system and muscles. However, the amount of sodium lost through sweat varies significantly between individuals. That's why it's impossible to say exactly how much sodium a particular person loses during a single sauna session. For regular sauna bathing, it's more practical to focus first on overall fluid loss and then consider how best to replace it. ###What About Potassium and Magnesium? Potassium and magnesium are also lost through sweating, but in much smaller amounts than sodium. Both are important for the body. Potassium supports proper muscle and nervous system function, while magnesium plays a role in energy metabolism and the functioning of muscles and nerves. However, regular sauna bathing doesn't automatically mean you need to reach for supplements simply because you've been sweating. What matters much more is getting enough of these minerals through your everyday diet. Good sources of magnesium include nuts, seeds, legumes, whole grains, and leafy green vegetables. Potassium can be found in foods such as potatoes, legumes, vegetables, and fruit. Minerals lost in smaller amounts during sauna bathing don't necessarily need to be replaced immediately afterwards. A balanced, nutritious diet over the long term is far more important. ###How Much Water Do We Lose During Sauna Bathing? This brings us to a much more practical question for the average sauna visitor. How much fluid do I actually lose? The answer depends on the length of your sauna session, temperature, number of rounds, humidity, sweating intensity, and individual factors. If you're curious, you can try a simple experiment. Weigh yourself before and after sauna bathing. The short-term difference in body weight is mainly due to water loss. You don't need to do this every time. Even a single measurement can give you a useful idea of how your body responds to a particular sauna routine. ###A Sauna Is Not a Marathon It's important not to apply sports hydration recommendations to sauna bathing without considering the differences. An endurance athlete who spends several hours running or cycling in hot conditions may lose several litres of sweat and significant amounts of sodium. Someone completing a few standard sauna rounds is in a very different situation. That's why regular sauna bathing doesn't automatically require the same rehydration protocols used in endurance sports. Fluid replacement should reflect actual losses. And this is where the type of water you choose after your sauna session becomes interesting. ###Not All Mineral Waters Are the Same Mineral water can be a useful part of your hydration routine because, in addition to water, it contains dissolved minerals. However, the mineral composition can vary significantly between different waters. The Czech National Health Information Portal (NZIP) provides an example of a generally suitable mineral water composition: 40–80 mg/l of calcium, 20–30 mg/l of magnesium, a calcium-to-magnesium ratio of approximately 2–3:1, and sodium below 150 mg/l. It identifies this composition as potentially beneficial during physical activity, for example. For everyday fluid replacement, it also recommends table water as a suitable choice. Comparing different waters makes it clear just how much their mineral profiles can vary. The Czech National Health Information Portal (NZIP) provides an example of a generally suitable mineral water composition: 40–80 mg/l of calcium, 20–30 mg/l of magnesium, a calcium-to-magnesium ratio of approximately 2–3:1, and sodium below 150 mg/l. It identifies this composition as potentially beneficial during physical activity, for example. For everyday fluid replacement, it also recommends table water as a suitable choice. Overview of Mineral Waters Mineral waters can vary significantly in their composition. The main differences lie in their sodium, magnesium, calcium, and potassium content, which also influences when each type of water may be most suitable. Lightly Mineralized Waters Aquila Sodium 15 mg/l · Magnesium 9 mg/l · Calcium 36 mg/l · Potassium 4 mg/l Suitable for sports and hot weather. According to the NZIP comparison, certain restrictions apply to people with heart conditions or high blood pressure. Bonaqua Sodium 1 mg/l · Magnesium 5 mg/l · Calcium 35 mg/l Suitable as everyday drinking water, during sports, and for people with heart conditions. Restrictions apply to people with high blood pressure or kidney disease. Dobrá voda Sodium 5 mg/l · Magnesium 8 mg/l · Calcium 6 mg/l · Potassium 7 mg/l Suitable as everyday drinking water and during sports. Toma Natura Sodium 1 mg/l · Magnesium 6 mg/l · Calcium 26 mg/l · Potassium 3 mg/l Suitable during sports, extreme heat, and for people with heart conditions. Restrictions apply to people with kidney disease. Waters with Higher Mineral Content Evian Sodium 5 mg/l · Magnesium 24 mg/l · Calcium 78 mg/l · Potassium 1 mg/l Suitable as everyday drinking water and during sports. It has a higher calcium content and, according to the NZIP comparison, may be less suitable for people with heart conditions. Mattoni Sodium 61 mg/l · Magnesium 25 mg/l · Calcium 98 mg/l Suitable during sports and hot weather. Restrictions apply to people with heart conditions or high blood pressure. Hanácká Sodium 277 mg/l · Magnesium 71 mg/l · Calcium 270 mg/l · Potassium 16 mg/l A highly mineralized water listed in the comparison as suitable for extreme sports. Not recommended for people with heart conditions, high blood pressure, or kidney disease. Mineral Waters Available at SALORI Il sano Sodium 26.8 mg/l · Magnesium 55.8 mg/l · Calcium 65.8 mg/l A relatively balanced mineral profile with notable amounts of magnesium and calcium. Bílinská kyselka Sodium 1,780 mg/l · Magnesium 48.8 mg/l · Calcium 140 mg/l · Potassium 81.2 mg/l A highly mineralized water with a very high sodium content and a significant concentration of bicarbonates. Vincentka Sodium 2,170 mg/l · Magnesium 19.1 mg/l · Calcium 304 mg/l · Potassium 143 mg/l A natural medicinal mineral water with exceptionally high total mineralization and substantial amounts of sodium, calcium, and potassium. Na = sodium, Mg = magnesium, Ca = calcium, K = potassium. The mineral content of commonly available waters and information about their suitability are based on a comparison published by the Czech National Health Information Portal (NZIP). Il sano, Bílinská kyselka, and Vincentka were not included in the NZIP comparison; their values are listed separately based on available professional chemical analyses. Mineral concentrations may vary depending on the specific laboratory analysis and year of testing. ###Why Have We Chosen These Particular Mineral Waters? We didn't want to offer just one mineral water as the answer to everything. Instead, we selected waters with different mineral profiles, each offering its own distinct characteristics. Il sano – A Balanced Mineral Profile Il sano has a total mineral content of approximately 717 mg/l and contains 55.8 mg/l of magnesium, 65.8 mg/l of calcium, and 26.8 mg/l of sodium. What makes this water interesting isn't an exceptionally high concentration of any single mineral. Quite the opposite. It has a relatively balanced mineral profile, with notable amounts of magnesium and calcium. That's why we offer it at SALORI as a mineral water suitable for a regular sauna routine. Not as an "electrolyte drink", but as a quality mineral water that naturally complements your daily hydration. Bílinská kyselka – High Mineral Content Bílinská kyselka is a completely different type of mineral water. It has a total mineral content of 7,412 mg/l and contains approximately 1,780 mg/l of sodium, 48.8 mg/l of magnesium, 140 mg/l of calcium, and 81.2 mg/l of potassium. Its bicarbonate content is also particularly high. This high concentration of bicarbonates and overall mineral content is what sets it apart from ordinary mineral waters. At SALORI, we offer it to guests who prefer a highly mineralized water after sauna bathing and want to enjoy its distinctive composition. With water this rich in minerals, there's no need to drink large quantities. Even a small serving is enough to appreciate its unique character. Vincentka – For Those Who Want to Take Their Sauna Routine a Step Further Vincentka has a character of its own. Classified as a natural medicinal mineral water, it has an exceptionally rich mineral composition. It contains 2,170 mg/l of sodium, 304 mg/l of calcium, 143 mg/l of potassium, and 19.1 mg/l of magnesium. Its total mineral content reaches approximately 9,060 mg/l. Its high sodium content and overall concentration of minerals make Vincentka one of the most distinctive mineral waters available. And that's precisely why it has its place at SALORI. Vincentka is for those who want to take their sauna routine a step further. ###Three Waters, Three Different Approaches This is exactly why we believe it makes sense to offer several types of mineral water at SALORI. Il sano provides a more balanced mineral profile for everyday hydration. Bílinská kyselka offers a significantly higher concentration of minerals and bicarbonates. Vincentka is a highly mineralized natural medicinal water with a distinctive composition. The key is simply to understand what we're drinking, why we're drinking it, and what our bodies have actually lost during sauna bathing. ###When Should We Pay More Attention to Electrolytes? For regular sauna bathing, most people can meet their needs through normal hydration and a balanced diet. The situation changes when significant heat exposure is combined with physical exertion – for example, after prolonged exercise, spending time in hot conditions, or several hours of heavy sweating. In these cases, it may be worth considering not only fluid intake but also sodium and overall electrolyte replacement. Even then, however, more electrolytes don't automatically mean better results. Replacement should reflect actual losses. ###You Don't Need to Drink Everything at Once After a Sauna After heavy sweating, it's natural to feel thirstier. But there's no need to replace all lost fluids at once by drinking a large amount of water. It's better to drink gradually according to your thirst and give your body time to process the fluids. If you've been sweating heavily, mineral water or a regular meal can also help replace some of what you've lost. The goal isn't to drink as much as possible. It's to gradually restore your body's balance. ###Give Your Body What It Needs After a Sauna Sauna bathing doesn't have to be a complicated process of counting litres of water and milligrams of minerals after every round. It's enough to pay attention to what your body is telling you. Feeling thirsty? Have a drink. Sweated heavily? Replenish some minerals along with your fluids. Feeling hungry? Enjoy something light and nourishing. These simple habits are often the foundation of effective recovery. And perhaps that's one of the most rewarding parts of sauna bathing – taking a moment to slow down, replenish what you've lost, and let your body do its work in peace.