Have Diabetes? Think Twice Before Soaking in a Hot Bath

Love the soothing feeling of a long soak in a warm bathtub? If you have diabetes, you can enjoy its relaxing benefits, but there are a few precautions you should take to stay safe.

Diabetes can cause nerve damage over time, resulting in the loss of feeling in your feet, notes the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). This condition, called diabetic neuropathy, increases the likelihood of unknowingly burning your feet in a very hot bath, making it important to ensure that the water temperature is safe.

Because neuropathy can prevent your extremities from gauging the real temperature of your bathwater, "people with peripheral neuropathy cannot just step a foot on the water and say, 'Oh, this is fine,'" says Rohit Moghe, PharmD, an ambulatory care and population health clinical pharmacist with St. Mary Medical Center Trinity Health Mid-Atlantic in Langhorne, Pennsylvania, and a spokesperson for the Association of Diabetes Care and Education Specialists.

Instead, use a thermometer to check the water temperature.

Dr. Moghe says to also make sure that you don't have any cuts or burns before getting into a hot tub, especially a public one, as this can lead to infection.

To take proper care of your feet, the NIDDK recommends washing them every day in warm (not hot) water and cautions against long hot soaks in the tub because doing so can dry out your skin. After washing and drying your feet, including between the toes, consider using foot powder or cornstarch to absorb any excess moisture and prevent infection.

Some people add Epsom salts — also known as magnesium sulfate — to their bathwater, thinking it will ease swelling and arthritis pain, but this isn't recommended for people with diabetes unless your doctor tells you otherwise, according to the Mayo Clinic.

The Mount Sinai Health System notes that some people with diabetes may have deficiencies in the mineral magnesium itself. But correcting that situation will take increasing magnesium consumption, be it through a supplement or dietary changes, something that soaking in the salt version can't do.

"Do not believe anything out there that says you can absorb magnesium from bathing in Epsom salt," Dr. Moghe says. "Nothing substitutes for the magnesium that we get from our diets or, in some cases, from dietary supplements."

According to the Mayo Clinic, just a few servings of magnesium-rich foods, such as nuts, seeds, whole grains, leafy vegetables, milk or yogurt, can improve magnesium levels.

​Read more:​ Many of Us Don't Get Enough Magnesium — Here's What You Need to Know About this Nutrient

A study published in the journal ​Temperature​ in March 2017 found that soaking in a hot bath can mimic the effects of exercise on lowering blood sugar. This has to do with the way that heat alters insulin absorption. According to the Centers for Disease Control and Prevention, extreme heat can cause blood vessels to dilate, which makes insulin absorb more quickly, in turn lowering blood sugar.

However, exercise and hot soaks aren't comparable, says Dr. Moghe.

"There's a huge difference in how the internal temperature is increased. With exercise, your muscle movements are increasing the internal temperature from the inside out, whereas with a bath or sauna experience, you're increasing the internal temperature from the outside in," he explains. "This is the lazy man's way of skirting around exercise requirements recommended by pretty much every single diabetes organization."

Dr. Moghe says that hot baths can be a helpful way to recover and relax, which can be beneficial for people with diabetes, but they shouldn't replace exercise as a means of lowering blood sugar. And that means aiming for a minimum of 150 minutes a week of moderate physical exercise.

​Read more:​ How Exercise Can Help Manage Type 2 Diabetes, and the Best Workouts to Do