How to Take the Most Relaxing Bath, According to Science

Bathing has had quite the journey. It's gone from a public social activity in ancient Rome to something done in the privacy of our own homes—first for cleanliness and hygiene, and eventually, as an indulgent way to relax.

Unlike many of the other suggested ways to show yourself some love, taking a bath is inexpensive and relatively accessible (depending on tub availability, of course). Better yet, baths are customizable and just for you—meaning you don't have to take into account what someone else wants. You're free to create the bath of your dreams and indulge in self-care.

And there are ways to elevate this experience to make it the most optimal for your body and mood. From finding the ideal bath timing and water temperature to using bath bombs and oils, below are some science-based strategies and guidelines to improve your experience in the bathtub.

How to Measure the Ideal Bath Temperature

Because most standard bathtubs don't come with a built-in thermometer, the temperature is something you'd have to measure on your own (if you really want to be scientific about it). Or, if you're in the market for a new tub, there are newer varieties with digital valves that let you set and control the temperature of the water.

Optimal Temperature

There isn't a single, "ideal" temperature for bathwater—it comes down to personal preference and the purpose of your time in the tub. For most people, comfortable bathwater is around 100 degrees Fahrenheit, says Michael Marbach, the director of product marketing at Kohler.

And he should know: The company has been in the bathtub business since 1873, when its founder, John Kohler, heated a cast iron horse trough/hog scalder and covered it with enamel—introducing the modern version of the bathtub. In Marbach's current position, he uses science and research to create the ideal bathing experience, including tub and bathroom design.

Specific Temperature Guidelines

How to Get Squeaky Clean

If your bathtime goal is to get as clean as possible, then Melissa Piliang, MD, a dermatologist with the Cleveland Clinic, does have a number in mind. Though she doesn't reveal how she arrived at this temperature, in an interview with the Wall Street Journal, she explains that bathing in water 112°F or lower is the optimal temperature for washing away environmental dirt and bacteria.

How to Reduce Moisture Loss

Age also is a factor, Dr. Piliang notes. The epidermis is covered with a protective fatty lipid layer that not only keeps dirt and germs out but also keeps moisture sealed in. The older we get, the longer it takes our skin to replace that lipid layer. "As we age, we have less tolerance for hot water, which may result in dry, itchy, red skin and possibly even eczema," she explains.

Unfortunately, even your favorite moisturizer can't replenish your skin's natural oils, Dr. Piliang adds. Keep your bath temp less-than-scalding to protect your skin from irritation, especially if your skin tends to be on the dry, sensitive side.

How to Increase Comfort

Meanwhile, if you're in the bath for relaxation purposes, the correct water temperature is simply the one that feels right to you. Perhaps you were caught in the rain without an umbrella, and by the time you get home, your clothes are soaked through and you're so cold that you can feel it in your bones. In that scenario, you might opt for a warmer bath than usual (and a warmed towel to match).

Or, let's say you live in a home without air conditioning, and during a heat wave, the only thing that brings you relief is lounging in a lukewarm bath while sipping a cold beer and reading a book. Again, it all comes down to what you want to get out of any particular bath.

How to Balance Your Body

According to Marbach, consider doing a cool rinse after a hot bath (or shower). "Heat penetrates and forces blood flow and circulation," he explains. "A cool, neutral rinse after a hot bath or shower brings the body to a state of homeostasis—a balanced state."

How to Sleep Well

Taking a bath in water that's a neutral temperature—meaning that it's similar to the temperature of the human body, or around 94-98°F—can be beneficial before bed. "This can provide a relaxing effect on the nervous system of the body," Marbach says.

The Perfect Timing for a Bath

How Long to Bathe

Aside from factoring in pruney fingers, is there anything else we should consider when deciding how long to stay in the tub? Not really, says Marbach, who recommends "soaking for as long as it is comfortable and enjoyable."

Thanks to Kohler's own research, however, we do know that nearly 50 percent of bathers enjoy staying in the bath for around 20 minutes. And according to a study published in the journal Sleep Medicine Reviews that looked at bathing before bedtime, 10 minutes is enough time in the tub to reap the sleep-promoting benefits.

When to Bathe

Is there a best time of day for a soak? Marbach says Kohler's data indicates that the evening is the most popular time for a bath, followed by the early morning. "I could see there being some benefit [of a morning bath] for people who have stiff joints—a bath could help loosen joints ahead of the day," he says. "A quick bath could also increase blood flow and potentially help wake a person up."

Want to improve your sleep quality? The Sleep Medicine Reviews research also found that bathing one to two hours before going to bed is good for our "temperature circadian rhythm" because it helps us fall asleep faster and improves our sleep quality. Scheduling baths around our bedtime improves blood circulation between our body's core to our hands and feet, which, in turn, cools the whole body, preparing it for sleep.

Pro Tips for Using Bath Products

While some prefer their baths au naturel, others like to enhance their soak with products like bath bombs or oils. Before getting into specifics, a word of caution from Marbach: Go ahead with the bath products in standard tubs, but "if you're bathing in a jetted bath—like a whirlpool or BubbleMassage experience—you need to follow the guidelines of your particular bath carefully, as adding certain elements to your water can cause clogging issues in the system."

How to Use Bath Oils

Adding a few drops of bath oil to your soak not only enhances the experience with an enticing and relaxing aroma, but it can also leave you with softer skin. The key here is checking the label to make sure it's safe to use in the bath. While some people opt to use pure essential oils over products formulated specifically for baths, that's not always a great idea.

Essential oils like lavender, lemon, and eucalyptus come with benefits. But other oils—like black pepper, clove, and peppermint—can irritate the skin. To make a safe, DIY bath oil, the Tisserand Institute recommends blending five to 20 drops of essential oil with one tablespoon of carrier oil (like grapeseed, jojoba, almond, or argan oil). Add the oil right before you're about to get into the bath to keep it from evaporating.

How to Use a Bath Bomb

Using a bath bomb is pretty straightforward: Fill the tub with water of your desired temperature, drop in the bomb, and marvel as it fizzes and dissolves, dispersing soothing ingredients into your bath. Fun fact: Bath bombs were invented in 1989 by Lush co-founder Mo Constantine, as a more skin-friendly alternative to bubble baths. With such a wide variety of these bubbling balls out there—including recipes for DIY bath bombs—we'll leave the decisions up to you.