Sweating helps cool down our bodies, but it also leads to fluid loss. If we lose more water through sweating than we drink, dehydration can occur. In hot weather, especially during physical activity, we can lose several litres of fluid per hour (1) (2).

At the start of summer, our bodies are not yet accustomed to the heat, so our sweat contains a significant amount of salt compared to later in the season. This puts us at risk of hypotonic dehydration, where we lose water and electrolytes but only replace them with water. Sodium plays a vital role in retaining water, so it's important, especially in the early stages of heat waves, to not only stay hydrated but also replenish salt. A simple way to do this is by having a salty snack during or after physical activity (3).

Dehydration can be dangerous. It impairs sweating and reduces blood flow to the skin, making it harder for the body to cool down and increasing the risk of heatstroke. Dehydration can also lead to kidney damage, cramps, cardiovascular issues, and altered consciousness. Studies have shown that repeated mild dehydration can cause permanent kidney damage (5).

Not all fluids are equally effective in combating dehydration. Alcohol, coffee, and sugary drinks act as diuretics, increasing urine production and water loss (4). Fresh water is the best choice, and we can conveniently refill our bottles from drinking fountains throughout the city using the Tap Water Ljubljana*app. This app helps us find the nearest drinking fountain, provides descriptions and photos, and shares other water-related points of interest nearby (6).

By using drinking fountains and reusable bottles, we contribute to reducing waste and minimising our impact on the environment.

*You can download the app from Google Play (Android) or App Store (iOS).