Saunas, particularly infrared saunas, are widely praised for their health benefits, from relaxation to detoxification. However, some people report experiencing diarrhoea after a sauna session, which can be both uncomfortable and puzzling. If you’ve ever wondered why this happens, you’re not alone. In this article, we’ll delve into the science behind this phenomenon and explore the potential reasons why saunas might cause digestive upset in some individuals.
Understanding Diarrhoea: A Quick Overview
Diarrhoea, often colloquially referred to as "the runs," is characterised by loose, watery stools and frequent bowel movements. This condition occurs when the intestines fail to absorb enough water or when they secrete excess fluid. While acute diarrhoea is usually short-lived and harmless, chronic diarrhoea can lead to dehydration, nutrient loss, and other health complications.
Globally, diarrhoea remains a significant health concern, causing hundreds of thousands of deaths annually, particularly in regions with poor sanitation. However, in most cases, acute diarrhoea is triggered by factors such as food intolerances, infections, stress, or even certain lifestyle habits. So, how does sauna use fit into this picture? Let’s examine four potential reasons.
Reason 1: Stress Hormones and Their Impact
Saunas, especially for beginners, can be physically demanding. Research shows that sauna use can significantly elevate stress hormones like adrenaline and noradrenaline, which remain elevated even after the session ends. While cortisol levels (another stress hormone) may not rise consistently, the spike in adrenaline and noradrenaline can have a noticeable effect on the body.
Stress, in general, is a well-known trigger for digestive issues, including diarrhoea. Medications that increase adrenaline levels, for example, often list diarrhoea as a common side effect. Similarly, the stress of an intense sauna session—particularly if your body isn’t accustomed to it—can stimulate a similar response.
If you’re new to saunas or pushing your limits with long or overly hot sessions, your body might react by releasing stress hormones that disrupt your digestive system. The result? An unwelcome case of diarrhoea.
Reason 2: Detoxification and Its Side Effects
One of the most touted benefits of saunas is their ability to aid detoxification. Through sweat, the body eliminates toxins such as heavy metals and environmental chemicals. However, this process isn’t always gentle. As toxins are released from fat cells and enter the bloodstream, they can temporarily overwhelm the body’s detoxification pathways.
Detoxification can manifest in various symptoms, including headaches, fatigue, and, yes, diarrhoea. This is because the body uses multiple channels to expel toxins, including the digestive system. If your body is working hard to eliminate toxins, it’s possible that your intestines might respond by speeding up transit time, leading to loose stools.
To mitigate this, consider shortening your sauna sessions or reducing the temperature. Additionally, ensure you’re eating a balanced diet rich in fibre and staying hydrated to support your body’s natural detox processes.
Reason 3: The Fever-Like Effect of Saunas
Saunas, by design, raise your core body temperature, mimicking the effects of a fever. This artificial fever can stimulate the immune system and promote healing, but it can also have unintended side effects. Studies on whole-body hyperthermia (a controlled method of raising body temperature) have shown that diarrhoea is a common side effect, alongside nausea and vomiting.
While saunas typically don’t raise body temperature to the same extreme levels as hyperthermia treatments, some individuals may still experience a fever-like response. If your body is particularly sensitive to heat or if you’re spending too much time in the sauna, this could trigger diarrhoea as a side effect.
Reason 4: Dehydration and Its Role
Dehydration is a well-known consequence of excessive sauna use, but its connection to diarrhoea might surprise you. Severe dehydration can increase intestinal permeability, making it easier for toxins and bacteria to disrupt your digestive system. A recent study found that losing 3% or more of your body weight through sweating during a sauna session could lead to this effect.
While diarrhoea is more commonly associated with fluid loss, dehydration itself can sometimes be the culprit. To avoid this, it’s crucial to drink plenty of water before, during, and after your sauna session. Electrolyte-rich beverages can also help replenish lost minerals and maintain hydration levels.
Should You Be Concerned?
In most cases, diarrhoea after a sauna session is a temporary and harmless reaction. It’s often a sign that you’ve pushed your body too hard, whether through excessive heat, prolonged sessions, or inadequate hydration. For the vast majority of people, this issue resolves on its own once they adjust their sauna habits.
However, if diarrhoea persists or becomes a recurring problem, it’s worth consulting a healthcare professional. Persistent symptoms could indicate an underlying health issue that needs attention.
Practical Tips to Prevent Sauna-Induced Diarrhoea
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Start Slowly: If you’re new to saunas, begin with shorter sessions at lower temperatures and gradually build up your tolerance.
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Stay Hydrated: Drink plenty of water before, during, and after your session. Consider adding electrolytes to your water for better hydration.
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Eat Well: Consume a balanced diet with adequate fibre to support your digestive system.
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Listen to Your Body: If you feel dizzy, nauseous, or overly fatigued, exit the sauna and cool down.
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Avoid Overdoing It: Limit your sessions to a reasonable length and temperature to prevent overexertion.
Final Thoughts
While diarrhoea after a sauna session can be inconvenient, it’s usually a sign that your body is adjusting to the stress of heat and detoxification. By understanding the potential causes and taking steps to moderate your sauna use, you can enjoy the benefits of saunas without the unpleasant side effects.
If you’re interested in learning more about the health benefits of infrared saunas, including their effects on stress, fatigue, and immune function, be sure to explore our comprehensive guide on the topic. Remember, moderation and mindfulness are key to making the most of your sauna experience!