Can a Sauna Cause Diarrhoea?

Occasionally, but quite rarely, we're asked a rather unusual question: "Is sauna causing me diarrhoea, and how this happened?!"

In this blog post, we delve into the science behind several possible reasons for how the use of an infrared sauna may cause you diarrhoea..

Warning: the topic we are about to discuss affects people quite profoundly, so it's probably best if you aren't eating or drinking right now.

What is "Diarrhoea", "Dysentery", Or "The Runs"

With the "runs" everyone knows what I mean but tackle the issue from a more scientific definition:

If you have diarrhoea or "the runs", your stools have become very loose and are paired with tons of water. That problem originates because either your bowels don't absorb much water anymore or they expel too much of it. Diarrhoea is a sign that your bowel movements have been impaired and that food isn't properly digested.

Diarrhoea can have many different causes, types, and solutions - so there's no one monolithic phenomenon called "diarrhoea" (1; 2; 3). And while the condition seems harmless to many people in the developed world, diarrhoea still causes 200,000 deaths every year on a worldwide basis.

Why? Acute diarrhoea isn't dangerous in most cases. In the long-term, however, diarrhoea can cause a mineral loss in the human body and even eventually the dreaded death. In this blog post, I'll be talking about the occasional acute diarrhoea that people may have after an infrared sauna session.

Food intolerances, viruses and bacteria, poor hygienic conditions, improper gut microbiome makeup, and parasites are some of the main causes of acute diarrhoea.

Interestingly enough, infrared sauna is good for gut health, and studies have shown that far-infrared can reduce bloating and IBS symptoms. So how then can an infrared sauna give you diarrhoea?

Reason 1: High Levels Of Stress Hormones

Several studies have actually explored the effects of saunas on stress and hormone levels.

For instance, the "cortisol" hormone that's responsible for increasing the body's breakdown of tissues doesn't seem to increase with sauna use - although studies are contradictory (4; 5; 6). Adrenaline and noradrenaline, however, which are both stress hormones, can more than double though and stay elevated after a session (7; 8; 9).

And, even though there is no research directly linking these neurotransmitters to diarrhoea, stress in general does increase diarrhoea risk (10; 11; 12; 13).

So here's why that dynamic matters:

Drugs that directly increase stress hormones such as adrenaline (epinephrine) also have acute diarrhoea as a common side-effect (14; 15).

If you're not using saunas daily, then they can be very stressful to the body, especially if you stay in too long. A similar concept would be when you're starting to exercise after years of doing nothing - your body is simply not used to the stimulus and might feel very stressed initially.

Hence, your sessions might be so intense because you've not gotten used to the stimulus that your body pumps out tons of stress hormones. These stress hormones can cause diarrhoea, in turn.

Acute diarrhoea is harmless here, but, inconvenient, of course.

But, stress is not the only reason. Let's consider another reason as to why can infrared saunas give you diarrhoea, potentially:

Reason 2: A Strong Detoxification Response

There is ample proof that human beings detoxify through their skins (16; 17; 18). Popular online sources such as newspapers are usually not aware of that fact.

Detoxification can be hard on the body though, as chemicals from household products or heavy metals are removed from your cells and released into the bloodstream. If the body cannot easily get rid of those toxins, they may do more harm than good even. For that reason, detoxification should never be the first step in any healing process - you generally have to build up overall health first before detoxing.

The body has several methods of getting rid of toxins, which not only includes sweat but also your breath, your stools, and more. Before toxins are removed from your body they often travel an extensive journey through you. And, because detoxification increases rather than decreases stress on the body, it can be paired with increased symptoms.

Of course, infrared sauna detoxification is a primary way to increase detoxification in your body. And, with increased detoxification symptoms can appear, such as headaches, fatigue, low energy, feeling jittery, and, you guessed it: diarrhoea.

If you do get diarrhoea consistently after sauna sessions, try cutting down on the length or intensity of your sessions and observe how your body responds. Also, make sure to eat well throughout the day - including some fibre to help your digestive system remove toxins - and drink enough water for proper sweating.

If the diarrhoea sauna connection keeps coming up, then I'd recommend visiting a doctor because you might have an underlying health issue. Sauna risk shouldn't consistently cause diarrhoea over time!

Next up, there's another reason why you can get the runs:

Reason 3: A Feverish Response

Saunas, including infrared saunas, really heat up your core body temperature. The effect of sitting inside a sauna creates an artificial fever within your body.

If you heat up your body temperature to an extreme level, then infrared saunas can give you diarrhoea for sure. To find out why let's look at some of the research on fevers:

In studies using extreme heat - simulated with "whole body hyperthermia" - diarrhoea is actually a frequent side effect (19; 20; 21; 22). These studies are great because participants in them are usually heated towards what is commonly understood as a fever for a long period of time, up to several hours.

Vomiting and nausea are similar side-effects.

As a result of heating up your body, diarrhoea might be an infrared sauna side-effect. That side-effect is especially likely to occur if you don't have good heat tolerance.

Now, usually, most people won't raise their body temperature nearly as much with sauna sessions as they would with whole body hyperthermia sessions, however, this depends on how long you stay inside a sauna in the first place. And yet, individuals are different from each other with slightly different biological makeups.

Hence, even though diarrhoea might be decently uncommon as a side-effect of saunas, you might be an individual who is more susceptible to that side-effect.

Reason 4: Dehydration

Yes, really!

This reason is somewhat counterintuitive, but, in severe dehydration, some people will develop diarrhoea. A study even recently directly investigated this phenomenon and concluded that inside your intestinal system, sauna sessions where you lose 3% or more of your body weight can increase the permeability of that system (23).

Of course, the causal connection between dehydration and diarrhoea is usually explained the other way around: once you end up with diarrhoea, you're far more likely to end up dehydrated because you're now losing water from one additional place in your body. And, of course, that connection absolutely exists.

But, now it seems that dehydration itself caused by heating can also increase the risk of diarrhoea in some instances. Fortunately, this issue can easily be countered once again by how much water you drink during your sauna sessions.

And, losing 3% bodyweight usually is several pounds, so for this effect to happen, you'll really have to go crazy on your sauna sessions.

Can Saunas Give You Diarrhoea? Yes. Should You Worry? Generally Not!

So, let's zoom out and consider the bigger picture.

Overall, diarrhoea is thus very unlikely to happen and usually a sign you're going too hard during your sauna sessions, whether it's due to stress hormones, detoxification, an intentionally created fever, or extreme dehydration. In all cases, you're overexerting yourself

Also, for only a few per cent of people, the sauna causes diarrhoea problem is really relevant. For 95%+ of people, diarrhoea and saunas are a non-issue because it's acute and will pass.

And yet, you might be worried whether what you're feeling is normal. For that reason, I've given you several reasons why people might commonly experience this unfortunate side-effect.

The solution is also very simple: go easier on your sessions to lower the detoxification and fever response. Also make sure that you're drinking enough high-quality water and eating sufficient levels of food to support proper detoxification. Lastly, make sure to build up your heat tolerance over time. We recommend you learn more about the infrared sauna health benefits. Just remember, Rome wasn't built in a day and heat tolerance can't be either!

Frequently Asked Questions about Infrared Saunas and Digestive Health

Q: Can saunas cause diarrhea?

A: While it's not common, some people may experience a change in bowel movements, including diarrhea, after using an infrared sauna. This is often part of the detoxification process as your body eliminates toxins.

Q: Why is my poop watery after sauna?

A: Increased hydration from drinking water during your sauna session could potentially lead to looser stools. However, if this continues, it's best to consult a healthcare professional.

Q: Does sauna help upset stomach?

A: Many people find that the heat from a sauna can help with digestion and soothe an upset stomach. However, everyone is different, so results may vary.‍

Q: What are the symptoms of a sauna detox?

A: Sauna detox symptoms can include increased sweat, a temporary increase in fatigue, and changes in bowel movements. These are usually mild and temporary.

Q: Can a sauna cause stomach issues?

A: While rare, some people may experience temporary stomach discomfort as part of the detoxification process. Always listen to your body and adjust your sauna use accordingly.

Q: Does infrared sauna help with bowel movements?

A: Yes, the heat from an infrared sauna can stimulate the digestive system, potentially leading to more regular bowel movements.

Q: Can an infrared sauna cause diarrhea?

A: Some people might experience temporary changes in bowel movements, including diarrhea, as their bodies adjust to the detoxification process.

Q: What are the symptoms of infrared sauna detox?

A: Infrared sauna detox symptoms can include increased sweating, mild fatigue, and changes in bowel movements. These are typically temporary and a sign of your body eliminating toxins.

Q: Does infrared sauna detox the body?

A: Yes, infrared saunas are designed to help your body detoxify by promoting sweat, which can carry out toxins.

Q: Does sauna cause bowel movement?

A: The heat from a sauna can stimulate the digestive system, potentially leading to increased bowel movements.

Q: Does sauna help bowel movements?

A: Yes, many users of Infrared Saunas report improved digestion and regular bowel movements.

Q: Is the sauna good for your digestive system?

A: Saunas, particularly infrared ones, can stimulate the digestive system, promoting better digestion and potentially aiding in issues like bloating.

Q: Do saunas flush out toxins?

A: Yes, one of the primary benefits of using a sauna is its ability to help the body flush out toxins through sweat.

Q: Is it normal to have diarrhea after a sauna?

A: While not common, some people might experience temporary changes in their bowel movements as part of the detoxification process.

Q: Is sauna good for upset stomach?

A: Many find that the gentle heat of a sauna can soothe an upset stomach, though individual results may vary.

Q: Is the sauna good for IBS?

A: While more research is needed, some people with IBS report relief from symptoms after using a sauna. Always consult with a healthcare provider before starting any new wellness routine.

Q: What are the symptoms of detoxing from infrared sauna?

A: Symptoms can include increased sweating, mild fatigue, and changes in bowel movements. These are typically temporary and a sign of your body eliminating toxins.

Q: Why do I feel unwell after infrared sauna?

A: If you feel unwell after using an infrared sauna, it could be a sign of dehydration or overexertion. Always remember to hydrate well and listen to your body.

Q: Is the sauna good after a stomach virus?

A: It's always best to consult with a healthcare provider before using a sauna after illness. While saunas can promote overall wellness, it's important to allow your body time to fully recover.

Q: Does sauna affect bowel movements?

A: Yes, the heat from a sauna can stimulate the digestive system, potentially leading to more regular bowel movements.

Q: Does a sauna help with stomach bloating?

A: Many people find that regular use of a sauna helps with digestion and reduces symptoms of bloating.

Q: Do saunas actually release toxins?

A: Yes, one of the major benefits of saunas is their ability to help the body release toxins through sweat.

Q: Should you sauna before or after eating?

A: It's generally recommended to avoid eating immediately before a sauna session to prevent discomfort. However, staying hydrated before, during, and after your session is crucial.