Everything you should know about Hot Baths!

By Edd Lee LAc LMT MS
"Do you have a bathtub? Do you use it? Can you take a hot bath tonight?"

A set of questions that will be familiar to my regular patients. For more than 15 years, I have been asking these questions of each and every patient after their treatment. The more curious patients will counter with, “Why a hot bath?”, to which I respond with a couple of points off the cuff. I thought it is about time to pull together all the information I can find regarding baths, so I can justify my incessant hot bath advocacy.

Hot Baths in History & Around the World
Hot bath traditions date back to antiquity around the world. In Europe, the Romans spread the practice of bathing across their once vast empire. Actually the word spa is an acronym for the latin phrase Sanus Per Aquam, which translates to health through water. In Germany, doctors often prescribe soaking at hot springs resorts—called kurorts—to patients to reduce stress or treat chronic conditions such as rheumatism. “Kurs” usually last for three consecutive weeks and the cost is covered by health insurance.

Turkish baths, called Hammam are often associated with the culture of the Ottoman Empire. Hammam rituals typically begin with relaxing in a heated room to induce perspiration. Bathers typically move progressively to a hotter rooms, then wash in cold water, often followed by a massage. In traditional hammams, bathers are nude and genders are separated for modesty.
Japan has a long history of bathing, not surprising given the number of natural hot springs found in the Japanese islands. The springs were originally used by Buddhist monks for purification rituals. As the healing properties were discovered, people brought their ill relatives to soak. Over time public bathing became commonplace and a practical way to stay clean. These days, indoor plumbing has solved hygienic problems, but Japanese continue to be big fans of public bathing. Soaking in Japan’s onsen is done in the buff, prior to entering the water, visitors are expected to thoroughly wash themselves with soap and water. Men and women are often separated by gender and those with tattoos are typically turned away. 

In Taiwan, hot springs called Wen Quan are clustered around the city of Beitou, where the active volcano Yang Ming Shan is the source of the thermal waters. Unlike Japan, however, swimsuits are required to soak in the public pools. You might spot people placing small towels on top of their heads; theoretically, doing so will prevent you from fainting by lowering the temperature differential between your body and the geothermal water.

Given the long history and expansive reach, what do we know about the benefits of taking hot baths? Surprisingly, quite a few. Here’s what I was able to find.

Mental health benefit
Soaking in a warm bath could have a positive impact on mental health and relaxation, according to a small study of 38 participants published in the journal Evidence-Based Complementary and Alternative Medicine in 2018. The participants also reported reduced feelings of tension, anger, hostility, depression, and dejection. 

“Through a randomized study, the researchers found that baths can have a greater effect on mental health and anxiety than showering as a form of bathing,” says Michael I. Jacobs, MD, a board-certified dermatologist, and associate professor of dermatology at Weill Cornell Medical College. 

Along the same lines, a small pilot study of 45 participants published in BMC Psychiatry in 2020 found that taking warm baths twice a week, for as few as two weeks, can result in “clinically relevant improvement in depression severity,” when the person continues their usual mental health care routine.

Cardiovascular benefit

Taking hot baths may improve your cardiovascular health, according to a 2020 study out of Japan published in the journal Heart. The researchers observed more than 30,000 people between the ages of 40 and 59 over a span of 19 years, and found that participants who took warm baths frequently had a decreased risk of cardiovascular events, Dr. Warner says. 

There is also research suggesting that taking hot baths regularly may have a positive effect on a person’s vascular health, meaning the blood vessels, veins, and arteries responsible for blood flow. For example, a small 2016 study from the Journal of Physiology found that after eight weeks of testing, daily hot baths resulted in lower blood pressure and increased artery health for the 10 participants. “Hydrotherapy in a warm bath will increase peripheral blood flow, and this promotes healing of any irritated or damaged tissues,” Dr. Warner adds. 

According to Thomas Pontinen, MD, LCP-C, a double board-certified anesthesiologist and pain management specialist, physician and co-founder of Midwest Anesthesia and Pain Specialists, taking warm baths also increases vasodilation, which improves circulation. “Improved circulation comes with numerous health benefits, but from a pain management perspective, it’s important because blood is what carries essential nutrients and molecules to your musculoskeletal tissues,” he explains. “In instances where pain is coming from trauma to muscle tissue or connective tissue, circulation expedites the process where the body heals itself.”

Reducing Muscle and Joint Pain

Bathing can provide some much-needed relief for people dealing with painful muscles, joints, ligaments, and tendons, Dr. Pontinen says. This is because the warm water can help the tissues in your musculoskeletal system relax, which helps you heal faster, he explains.

This is especially true of mineralized water, like the kind found in natural hot springs (or in your tub, after adding water-soluble mineral sources, like Epsom salts), according to a 2021 study out of Ethiopia with more than 1,000 participants, published in the journal Inquiry. The researchers found that bathing in hot springs for three or more days can “have significant therapeutic effects on patients with musculoskeletal disorders” including rheumatoid arthritis—which affects approximately 1.3 million adults in the U.S.

“One of the main benefits is to help the body relax, help muscles to recover and heal, and to reduce pain,” Dr. Warner says. “Joints and stiff connective tissues will also feel better after a warm bath.” In addition to pain, bathing can also alleviate other types of muscular discomfort. “For sore muscles, a hot bath can reduce built-up tension, tightness, pain, and soreness,” Dr. Purdy adds.

Improved Sleep

Given that taking a warm bath can help some people relax, it’s not surprising it can also help promote a good (or at least better) night’s sleep. “Taking a bath at night may help you fall asleep and stay asleep, increasing your overall sleep quality, which is vital for your body to reset for the next day,” Dr. Purdy says. “It’s a great way to wind down, as it triggers the body and your mind to relax, which in turn can help you fall asleep.”

One way bathing accomplishes this is by supporting the body’s nightly temperature adjustment. “The body naturally undergoes a cooling phase when you begin to sleep, and a hot bath can give you a head-start with that phase,” Dr. Pontinen explains.

These benefits aren’t strictly anecdotal: A 2019 review of the findings of 17 studies on the effects of bathing on sleep concluded that taking a warm full-body bath, foot bath, or shower before bed for at least 10 minutes can improve sleep quality.

Better skin

You may not think of bathing as part of a skincare routine, but whether you opt for a bath or a shower, that’s exactly what it is. In addition to removing dirt on the surface of your skin, bathing in warm water also opens up your pores, allowing you to wash away built-up grime, according to the Cleveland Clinic. Plus, it softens the layers of dead skin cells on the outer surface of the skin, so that they slough off easily with a washcloth (or prepare your skin for your exfoliation method of choice).

“[Bathing] can also help you clear away the bacterial and fungal load from contact in your environment,” says Amy Zack, MD, a family physician at the Cleveland Clinic. “As that accumulates, it increases your risk of infection.”

Once again, the research on the dermatological benefits of bathing is limited, but the 38 participants in the small 2018 study published in the journal Evidence-Based Complementary and Alternative Medicine mentioned above reported an improvement in their skin’s condition after two weeks of bathing regularly.

Additionally, taking warm mineral baths can help treat acne and seborrheic dermatitis, according to a 2020 review of studies investigating the effects of bathing in warm, mineralized water for people with chronic inflammatory skin diseases, published in the Journal of Clinical Medicine. The article also concluded that warm baths in mineralized water can be especially beneficial for people living with atopic dermatitis and psoriasis.

Immune benefits

Immunology studies have found that soaking 20-30 minutes in a bath raises your core body temperature increasing white blood cell production and strengthening your body's ability to fight off infection. 

It's long been accepted that an increase in body temperature is helpful in fighting infection and inflammation. That's one of the main avenues our bodies respond to infections——by literally heating up with a fever! Researchers at the Roswell Cancer Institute found that lymphocytes, (particularly CD8+cytotoxic T-cells which are highly effective in destroying virus-infected cells) are significantly intensified in their ability to fight off infection by an increase in body temperature. So it's not surprising that recent studies utilizing hydrotherapy— particularly baths and saunas— have found that a 30-40 minute soak results in an increase in your body's production of these important infection-fighting white blood cells.
​
So you can see, there are so pretty significant arguments for taking hot baths regularly, particularly as an active New Yorker. Will this get you take baths more often? I can only hope. But I do hope this helps you to, at the very least understand, why I always ask you take a bath.