What junk hides in spas?

For centuries, humans have 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 local gods and bathing there was considered an act of worship.

It was the Romans, however, who created state aqueducts to enable 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 acts, sometimes with the slaves in charge of the baths.

Two millennia later, we still love public baths, even though many people now have their own hot tubs, or hot tubs, sales of which have surged 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. Bathing in a spa is often considered a luxury experience that is both relaxing and rejuvenating.

The warmth of bath water naturally dilates blood vessels, which helps muscles to relax and relieves painful joints. As well as 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 jacuzzi, everything we have on our skin is deposited in the hot water which swirls around us. This includes the roughly 100mg of feces that usually sits between our buttocks. So, when you relax in hot water, you are very likely to breathe in or swallow bacteria, viruses and fungi from your hot tub companion's body.

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.

  I love it when we swap feces.  . (DGLimages/Alamy Stock Photo)

Since hot tub owners are recommended to only change the water every three months or so, bacteria thrive. 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 that 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 temperature of the water in a hot tub (around 40°C) can also cause potentially serious health issues, such as overheating of the body, which can lead to feeling weak or even loss of consciousness, or even drowning.

This is particularly risky for pregnant women and children, as well as people with underlying health conditions, who should always consult their doctor before using a hot tub. 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 hot tubs (in hotels or spas) can be contaminated with 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.

These include E.coli, Staphylococcus aureus, Pseudomonas aeruginosa and Legionella pneumoniae. These hot tub pathogens can cause intestinal infections, diarrhea, sepsis, skin infections, urinary and respiratory tract infections, such as Legionnaires' disease. Legionella bacteria are regularly found in water droplets found in hot tub steam, and inhaling this contaminated steam can cause potentially fatal pneumonia.

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

If one still wants to enjoy a hot tub, can one check whether 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 hot tub water, it creates an irritant, a pungent smelling chemical called chloramine, which causes eye pain. when swimming in a public swimming pool.

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

Primrose Freestone, Senior Lecturer in Clinical Microbiology, University of Leicester

This article is republished from The Conversation under a Creative Commons license. Read the original article.