Fungi, viruses, bacteria… Here’s what a microbiologist found in spas – and it’s not appetizing

For centuries, humans bathed in public waters. Sometimes to wash, but more often for fun. In ancient Greece, baths were taken in fresh water, or in the sea, perceived as a sacred place dedicated to the local gods and bathing there was considered a act of worship.

However, it was the Romans who created state aqueducts to allow the construction of large-scale public baths. These were mainly used for relaxation, but also for intimate pleasures. Yes, it was often in the public baths that the Romans indulged in naughty actssometimes with the slaves in charge of the baths.

Two millennia later, we still love public baths, even though many people now have their own spas, or hot tubs, sales of which have seen a boom. sharp rise during the pandemic.

For those who don’t have one at home, there is the local gym or spa. And many hospitals have one. Indeed, hot tubs are commonly used for therapeutic purposes to relieve and treat joint inflammation in people with rheumatism or osteoarthritis. The use of a spa is often considered a luxury experience, both relaxing and regenerating.

The heat from the bath water naturally dilates the blood vessels, which helps muscles to relax and relieves painful joints. In addition to being physically soothing, the bubbling hot water and the company of people who share the experience with us can also engender psychological well-being.

Bacteria, viruses and fungi

However, we must not forget that when we enter a whirlpool, everything on our skin is deposited in the hot water which swirls around us. This includes the approximately 100 mg of feces which are usually found between our buttocks. Thus, when we relax in hot water, we are very likely to breathe in or swallow the bacteria, viruses and fungi of the body of his spa companion.

The more people in the bath, the higher the rate of faeces and sweat (and urine if someone has peed in the water). And these deposits serve as nutrients for bacteria.

Since spa owners are recommended to only change the water every three months approximately, the bacteria grow. For microbiological safety, most hot tubs that recirculate water are equipped with filters that eliminate microbes and their water is treated with microbicides (to eliminate germs) such as chlorine, bromine or other disinfectants which control the number of bacteria.

These chemicals are toxic and can irritate skin and eyes. This is why it is advisable to take a shower after the hot tub (before too). The water temperature in a hot tub (around 40°C) can also cause potentially serious health issues, such as overheating of the bodywhich can lead to a feeling of weakness or even loss of consciousness, or even drowning.

It is particularly risky for pregnant women and the childrenas well as people with underlying health conditions, who should always consult their doctor before using a spa. This is why we advise not to do sessions of more than 15 minutes in a spa and never unsupervised.

Dirty or disgusting?

While private hot tubs are relatively safe from a microbiological point of view, public spas (in hotels or spas) can be contaminated by infectious bacteria (germs), especially if the water is recycled.

The problem stems from the fact that users do not respect personal hygiene instructions and that water treatment is inadequate. Poorly maintained bathhouses can cause outbreaks of infections due to bacteria associated with the human body that survive in the water.

Among those figure E.coli, Staphylococcus aureus, Pseudomonas aeruginosa And Legionella pneumoniae. These hot tub pathogens can cause intestinal infections, diarrhoea, sepsis, skin infectionsurinary and respiratory tract infections, such as Legionnaire’s disease. There Legionella bacteria is regularly found in water droplets present in hot tub steam, and inhaling this contaminated steam can cause potentially fatal pneumonia.

The risk of infection from hot tubs is so great that the US Centers for Disease Control have published recommendations on how to prevent it.

If we still want to enjoy a hot tub, can we check if it is safe for health? There are some clear signs that let us know that a hot tub is full of germs. When urine and other bodily fluids such as sweat mix with the chlorine used to sanitize spa water, it creates an irritant, a pungent smelling chemical called chloramine, which causes eye pain. when bathing in a public swimming pool.

The more people who leave their bodily fluids in the water, the more the smell of the chloramine (similar to that of bleach) will be strong and the more likely it is that the spa will not have enough sanitizer and too many bacteria. Therefore, if a strong odor is emanating from a hot tub, it may be best not to enter it, even if the water seems clean and clear, although the water eventually becomes cloudier when it is not. is not sufficiently treated.