Hydration Needs During Sauna Use: Importance of Fluid Intake Before and After
Have you ever wondered how much water you need after using a sauna? Saunas can leave you feeling rejuvenated and refreshed, but they also have the potential to dehydrate your body. You don't have to worry about that because I’ll guide you through understanding your hydration needs during sauna use.
But before that, how much water does one lose when using a sauna? It’s important to note that sauna sessions vary in duration and temperature.
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What Studies Say About Sauna and Dehydration
There’s no doubt that sweating in a sauna can lead to a significant loss of water in the body. An exciting study by Podstawski R and colleagues evaluated the relationship between body mass index (BMI) and body mass loss (BML) induced by thermal stress in a dry sauna. Conducted on 674 sedentary students (326 women and 348 men) aged 19-20, the participants underwent two 10-minute sauna sessions with a 5-minute break in between.
The subjects were placed in a dry sauna, and their body mass was measured before and after the sessions to assess fluid loss. The researchers utilized nonlinear stepwise regression to analyze the correlation between BMI and BML, focusing on how different BMI categories affected the weight lost during sauna exposure.
The findings indicated that participants experienced significant body mass loss due to dehydration from sweating. On average, participants lost approximately 0.65 kg (or about 0.65 litres of water) after the sauna sessions, with variations based on individual characteristics such as BMI.
Notably, individuals classified as overweight or obese exhibited greater BML compared to those with normal or underweight classifications. The study concluded that higher BMI correlates with an increased risk of dehydration, emphasizing the importance of fluid replenishment during sauna use.
Additionally, the study highlighted that 1 kg of body mass loss typically corresponds to about 1 litre of fluid loss, reinforcing the notion that sauna sessions can lead to significant dehydration in a short period, often within just 15 minutes of exposure to high temperatures.
Now let’s discover why you need to hydrate before using the sauna.