Is 106 degrees too hot for a hot tub? Spa safety tips

hot tub temperature safety

A hot tub should be, well, hot … right? One of the benefits of soaking in a spa is the therapeutic effect of warm water. 

The truth: The temperature of your hot tub water temperature should never exceed 104 degrees. More than that, many users find that a temperature between 100 and 102 degrees is comfortable for most adults. If you have children soaking, you should take precautions and lower the water temperature.

So … is 106 degrees too hot for a hot tub? Absolutely.

Your backyard spa should be a place where you can relax, unwind, and spend time with family. Hacking your hot tub so it can be 106 degrees or hotter can cause health issues such as nausea or even stroke.

Keeping your spa water at a maximum of 104 degrees ensures that you can enjoy a safe, soothing soaking experience. 

hot tub temperature safety
Hot tub safety guidelines state that a spa should never be hotter than 104 degrees. A water temperature at 106 degrees or above is too hot to soak in safely.

Home spa safety guidelines

There’s one feature that every hot tub on the market is sure to have, no matter which model you choose. And we’re not talking about jets or LED lighting. It’s a temperature limit.

Following guidelines from the Consumer Product Safety Commission, the maximum temperature of a hot tub is 104 degrees.

The CPSC report states: 

“Soaking in a hot tub with water heated to 106 degrees Fahrenheit, for example, can raise human body temperature to the point of heat stroke (or impairment of the body’s ability to regulate its internal temperature). These conditions can be fatal even to fully healthy adults.”

These regulations, which apply to hot tubs manufactured in the United States, were first issued at the end of 1979. However, most manufacturers worldwide have adopted these safety regulations.

Temperature-regulating controls are required for manufacturers to obtain and keep their UL listing. A UL listing ensures that your hot tub is constructed properly and to the highest safety standard.

hot spring temperature
Many natural hot springs have a water temperature that exceeds 110 degrees. However, the hotter the water, the less time you should soak.

In hot water?

At-home spas are designed so that you can unwind and have fun, and the water temperature plays a key role in that relaxation.

So why does a hot tub only heat to 104 degrees? After all, many hot springs and other soaking spots might have water that’s at a higher temperature — even up to 115 degrees.

However, these hot springs and other public spots are not intended to be used for longer soaks. 

The recommended bathing time for hot springs depends on the water temperature. If the water is warmer than 104 degrees, you shouldn’t be in for longer than 5 minutes. 

And let’s be honest: Most people do not take the cover off their hot tubs to hop in for 5 minutes and then hop out. Even if that was the intention, it’s easy to lose track of time as you relax into the contoured hot tub seats. 

The warmer the water, the less time you should spend in it. You will also need to incorporate breaks, allowing your body temperature to return to normal.

hot tub benefits
People have sought the relief and therapy of warm water for thousands of years. Soaking in hot water provides many physical and health benefits.

Warm water therapy

Have you ever wondered why soaking in a hot tub feels good? Our average body temperature is 98.6 degrees. When you get in water that’s warmer than your body temperature, it has a soothing effect. 

Soaking in warm water raises your core body temperature, which causes several physiological changes. Your blood vessels will dilate, increasing the rate of blood flow, and decreasing your blood pressure.

Physical benefits of soaking in a hot tub:

Relaxation. As blood flow increases, your muscles will relax. You might also notice that pain decreases, too. 

Flexibility. When your muscles are relaxed, you can move through a greater range of motion. Many people enjoy using a hot tub for stretching and gentle exercise. 

Promotion of healing. The jet action found in spas can promote healing by providing even more oxygen to the area than is provided by warm water alone. The heat and pressure from the jets can also raise the level of antibodies and white blood cells delivered to the area, promoting the destruction of bad cells and stimulating the formation of new tissue.

Better sleep. Research shows that you will fall asleep more quickly and sleep better after soaking in a hot tub. How does a hot tub help sleep? The change in core body temperature helps induce sleep. People who struggle with chronic pain might also feel more relaxed after soaking, which will help at bedtime.

These physical health benefits of a hot tub can be realized by soaking in water between 102 degrees and 103 degrees. Raising the temperature of the water does not correspond with increased health benefits.

In fact, higher water temperatures might lead to the opposite.

heat stroke
You can put yourself at risk of heat exhaustion or even heat stroke if you soak in water temperatures above 104 degrees.

Signs of heat stroke

You’re standing outside on a hot summer day. You can feel your temperature begin to rise and the sweat begin to bead. 

Whether you are lying on the beach, working out, or soaking in a hot tub, your body will begin to sweat to help cool off the body. However, when you soak in water that’s too hot, you are not able to cool down. Your core body temperature can rise the longer you stay in the water.

It might feel relaxing but you could be overheating.

There are potential health risks when soaking in water that’s too hot, whether it’s 106 degrees or 110 degrees. 

You can become dehydrated, dizzy, or confused. In addition, overheating can lead to heat exhaustion or even heat stroke.

The signs of heat exhaustion include nausea, stomach cramps, headache, weakness, dizziness, and fainting. Heatstroke is dangerous and can cause bizarre behavior, hallucinations, seizures, and even death.

If you or someone you love is showing signs of heat exhaustion, you need to get out of the spa and cool down.

An important note: If you have a history of heart disease, high blood pressure, diabetes, or another chronic condition, you might need to lower the temperature of the spa water. 

home spa safety
There are myriad factors to consider when setting your hot tub water temperature, including who is using the spa and your personal comfort level.

Perfect hot tub temperature

How hot should your hot tub be? Setting your spa to the perfect temperature is just as much about personal preference as it is safety. 

While 104 degrees is the highest you can set the water temperature to, most people are comfortable soaking in water that’s between 100 degrees and 102 degrees.

Other considerations include whether you will have young children or pregnant women in your hot tub. 

The U.S. Consumer Product Safety Commission recommends an even lower hot tub temperature for pregnant women, at just 100.0 degrees. According to the American College of Obstetricians and Gynecologists, pregnant women should not let their core body temperatures rise above 102.2 degrees. 

Some say that children can soak in water between 100 and 102 degrees. However, the Pool and Hot Tub Alliance recommends an even lower water temperature — around 98 degrees.  

If you are unsure of your preferred spa temperature, consider setting the water to 99 degrees. You can gradually increase the water temperature if it does not feel relaxing. 

Keep in mind that it will take some time for the water to warm up if you increase the water temperature several degrees. 

More hot tub tips

Whether you want to install a hot tub or upgrade your backyard, our forum and its members offer tips and tricks.

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