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4 Reasons to Think Twice Before Getting Into a Hot Tub

The warm water can harbor risks to your health, especially if you're older

woman sitting in a hot tub and talking to another woman sitting on the side of the hot tub

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En español | Summer travel season is in full swing, and for some vacationers relaxation plans include a soak in a hot tub at a hotel, resort or vacation rental. But before you get your feet wet, especially if those feet have a few decades’ worth of miles on them, you should consider the health risks of dipping into a public hot tub.

A recent report from the Centers for Disease Control and Prevention (CDC) found a total of 208 confirmed outbreaks of illness associated with “treated recreational water” — primarily public swimming pools, hot tubs and water playgrounds — between 2015 and 2019. The outbreaks resulted in 3,646 cases of illness, 286 hospitalizations and 13 deaths. Most outbreaks occurred in June, July or August. Health experts suspect the actual numbers are even higher since many illnesses go unreported.

Hot tubs can be a particular concern for vacationers. During the five-year period, 1 in 3 water-related outbreaks were connected to hotels or resorts, according to the CDC. Of those outbreaks at hotels and resorts, the majority — 70 percent — were tied to hot tubs.

Here are four health-related reasons you may want to avoid hot tubs if you're an older adult.

1. The water can make you sick

Identifying a Healthy Hot Tub

Use your nose. If a hot tub smells like chlorine, that doesn't mean it's clean. In any treated water such as a hot tub, swimming pool or water playground, that “chlorine smell” occurs when chlorine mixes with an excess of urine, sweat and other contaminants. Bathers should take a shower for one minute before entering a hot tub. Doing so should remove about 70 percent of contaminants on the skin, according to the CDC.

Conduct your own inspection. Before going into the water, review the inspection score of a hot tub, either online or physically posted nearby. Alternatively, test strips can be purchased at hardware, pool supply or similar stores to check the chlorine, bromine and pH levels.

  • Chlorine should be at least 3 ppm (parts per million) in hot tubs.
  • Bromine, an alternative to chlorine, should read at least 4 ppm in hot tubs.
  • The pH level represents how effectively germs are killed and should be between 7.2 and 7.8.

The CDC warns hot tub users to avoid swallowing the water or even getting it in their mouths. Why? Because germs in the water can cause unpleasant and even life-threatening illnesses.

Start with cryptosporidium, or crypto for short. The parasite, which lives in fecal matter, can cause gastrointestinal illnesses, including diarrhea. Crypto can be spread when an infected person uses a hot tub. Older adults, as well as young children, pregnant women and people with compromised immune systems, are particularly susceptible. Anyone with diarrhea should avoid going into a hot tub to prevent the spread of crypto.

Even more common in hot tubs is Legionella pneumophila, a bacterium that can cause Legionnaires’ disease, a pneumonia-like lung infection that's potentially serious, particularly for those 50 and older. Symptoms of Legionnaires’ disease include:

  • Cough
  • Shortness of breath
  • Fever
  • Muscle aches
  • Headaches

In 2018 alone, health departments reported nearly 10,000 cases of Legionnaires’ disease. However, because the illness is typically underdiagnosed, it is believed the actual number may be up to 2.7 times higher than what was recorded.

A milder infection resulting from legionella known as Pontiac fever results in fever and muscle aches.

2. The steam can make you sick, too

While there's a risk of contracting Legionnaires’ disease or Pontiac fever by swallowing contaminated water, there's an even greater risk presented by inhaling contaminated water vapor emitted from a hot tub. Therefore, if you sit near a hot tub without ever going in, there is still a risk of getting very sick.

"When you turn the jets on in the hot tub, you're aerosolizing the water, you're making a mist of the water, you're putting it into the air,” said Michele Hlavsa, chief of the CDC's Healthy Swimming Program. “If those water droplets contain the bacteria and they're carrying that bacteria into the air, if you inhale them you can become infected."

Legionella likes warm water, and when chlorine or bromine levels drop, the germ can survive and multiply in the slime, called biofilm, that appears on the walls of some hot tubs. Those who are in the hot tub or lounging nearby may want to take caution if they see the slimy substance.

People who have weakened immune systems, former smokers, and those 50 and older should consider not using a hot tub or even sitting near one, says the CDC. Because the amount of water vapor around a hot tub can vary, there isn't a uniform distance from a hot tub that people with an increased risk for Legionnaires’ disease should maintain. But, it should be at least a few feet away, Hlavsa advised.

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3. You might get a rash

Pseudomonas is another bacteria partial to warmer water temperatures that can survive and multiply in a hot tub's biofilm. But rather than a respiratory infection, this germ can cause what's known as “hot tub rash.” The skin infection can affect hair follicles and result in red, itchy skin and pus-filled blisters.

"You develop a rash basically wherever your skin came in contact with the hot tub water, so people will often find a rash pattern similar to their bathing suits,” said Hlavsa. “The bathing suit is holding water against their skin."

To lessen the likelihood of hot tub rash, make sure to remove your swimsuit, wash it, and take a shower with soap after using a hot tub.

4. The heat can leave you woozy

Hot tubs have timers for a reason. When the water jets turn off, you should take a break, too. The timer to turn the jets back on is usually placed so that bathers have to get out of the water to reset it. If you see that the time is up, it's probably a good time to take a break from the warm water. This is especially true for older adults whose ability to regulate their body temperatures is compromised by age.

Since the heat from a hot tub expands blood vessels, causing blood pressure to drop, people who already have low blood pressure can pass out in a hot tub, which can lead to drowning. Drinking alcohol while using a hot tub can also combine with the heat to lower blood pressure and also impair judgment.

The CDC recommends that hot tubs be no hotter than 104 degrees Fahrenheit.

Aaron Kassraie writes about issues important to military veterans and their families for AARP. He also serves as a general assignment reporter. Kassraie previously covered U.S. foreign policy as a correspondent for the Kuwait News Agency’s Washington bureau and worked in news gathering for USA Today and Al Jazeera English.

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