The countdown continues on More Than Healthy’s Full Year of Resolutions, and this week we’re on Tip #43, the health benefits of hot baths. Or for me, the health benefits of a hot tub. One of my very favorite items we own is our hot tub. Before we got a sauna, I was in this hot tub every day. I still spend time here 3-4 times a week, and for sure after a big day of pickleball. In last week’s post about the health benefits of salt, we shared about the leg cramps I sometimes get after a big tournament. If I take a half-hour soak in the hot tub when I get home, I usually don’t get any cramps (as long as I’ve made sure to get enough salt that day too).
David likes the hot tub too, but he prefers a good long soak in a hot bath with Epsom salt and magnesium flakes. The combination of the heat plus the benefits of the salt and magnesium help him with his muscle recovery. (For more info on the health benefits of magnesium and salt, check out Tip #26 and Tip #42.)
The power of hot water to heal the body
The history of bathing (or thermal therapy) dates back to the beginning of time. Ancient peoples knew of the beneficial effects of thermal cures. Whole civilizations were built near hot springs. If you travel to Budapest, which sits on over 100 natural thermal springs, you can still soak in some of the thermal pools built there by the Romans prior to 300 A.D.
People have been soaking in bodies of warm water for centuries, just because it feels good. It’s only been fairly recently that research has begun uncovering a number of legitimate health benefits of doing so. In fact, until I researched this topic, I had no idea of the amazing science behind the benefits of a hot bath. I just knew they always made me feel better.
The benefits of hot baths are mostly attributed to thermotherapy. Thermotherapy is sometimes referred to as passive heating, or a temporary raise in core body temperature. This increase in temperature results in improved blood flow, tissue metabolism, and flexibility. The increased blood flow helps with healing by supplying protein, nutrients, and oxygen anywhere needed…to sore or hurt muscles, for example, or if you have an injury.
Let’s talk about some of the benefits we’ve discovered from hot baths…and the amazing science that backs them up!
Four health benefits of hot baths
Benefit #1: Hot baths soothe muscles
Post-workout is a great time to reap the benefits of hot baths. If I’ve had an extremely hard workout and I can get into the hot tub for 30 minutes, I notice that not only does the soreness immediately decrease, but I’m also not sore the next few days. If I don’t soak, I can experience pain for a few days while my muscles repair the damage I’ve done.
Heat therapy is commonly used to relieve pain. There are two types of heat therapy: dry heat and moist heat. Studies show that moist heat is more effective than dry heat, and it usually requires less effort and time for the same results.
Hot baths are a great form of heat therapy. A nice soak works on muscle pain and stiffness by improving circulation and blood flow to an afflicted area. Even a slight increase in temperature soothes discomfort and increases muscle flexibility. A hot bath relaxes and soothes muscles and heals damaged tissue.
Some compelling evidence for hot bath therapy
You probably know this is true simply from your own experience. But research backs it up – studies show that warmth can dramatically ease aches and pains. One study involved a group of men that experienced back pain. Using heat post-workout, there was an increase in pain relief by 138%. The study’s findings report that heat therapy was of significant benefit in the prevention and early phase treatment of low back delayed-onset muscle soreness.
In another study, participants had fibromyalgia and did heat therapy in a warm, chest-high pool three days a week. After 16 weeks, the group that did the therapy reported decreased pain and severity of their fibromyalgia as well as improved cognitive function (see more on this below). Researchers believe the improved cognitive function may be a side effect of not having to deal with the pain, as pain requires so much of our energy and focus.
Benefit #2: Hot baths may prevent or delay the onset of memory diseases
Improved cognitive function sounds really good to me. I’m interested in anything that has been shown to improve brain function. A groundbreaking study in Finland over a 20-year period showed that participants who took hot baths at least three times a week had a lower risk of Alzheimer’s and dementia – 66% lower! If taking a relaxing hot bath a few times a week lowers my risk of memory loss by two-thirds, count me in!
The heat from a bath causes the blood vessels to dilate, improving blood flow to the brain. Not only does a hot bath help with blood flow, it also makes the blood more oxygenated. And, a hot bath helps kill bacteria and improves immunity. That’s enough to encourage me to jump in a hot bath a few times a week.
Benefit #3: Hot baths can help improve cardiovascular health
I am fascinated to see how many of the studies done on the benefits of hot baths reveal that it can actually be as effective for heart health as a 30-minute workout. Relaxing in a warm tub also relaxes your blood vessels. As mentioned above, the heat causes them to dilate, making it easier for blood to flow through. This temporary decrease in blood pressure is similar to the effects on blood pressure from exercise.
In Japan, where the benefits of hot baths have been embraced for centuries, a 20-year study of more than 30,000 people found that those who bathed daily were 28% less likely to develop cardiovascular disease. They were also 26% less likely to have a stroke compared with those who took baths less than twice a week.
Although we will always promote the healthy benefits of exercise, a hot bath might be a great alternative for when you’re just not able to get in a workout. Sometimes my clients are just too tired or depressed and have low motivation to exercise. When that happens, hot baths are a way to get some of the same benefits without the exertion. Additionally, a hot bath might be a beneficial addition to your routine when your body needs to rest.
A related benefit – hot baths help heart and mental health
Research shows that the same pathways in the brain that regulate body temperature are involved in depression. We’ve talked a lot about how exercise produces “happy chemicals” in our bodies, like dopamine and serotonin. Turns out that a hot bath can do the same. Evidence suggests that raising your core body temperature (like by soaking in a hot tub) causes changes in mood-regulating hormones like serotonin.
Some of the research even indicates that, when it comes to serotonin, the benefits of hot baths might be greater than exercise. Studies back this up. In a study of 45 people with depression, those who took at least two 20-minute baths per week had less depression than participants who exercised for 45 to 50 minutes twice a week.
Wow. That’s a pretty big benefit from two short baths per week.
Benefit #4: Hot baths help you sleep better
Surprise! We’re talking about sleep once again. When it comes to your health, nothing is more important than getting quality sleep! But really, who doesn’t know that a hot bath can improve your sleep? Moms have been giving their babies warm baths before bed for decades. What might surprise you is that hot baths are directly linked to our circadian rhythms.
Our body needs to cool off by a few degrees as we prepare to sleep. Counterintuitively, taking a hot bath speeds up this process. It does so by improving blood circulation from the core of the body to the hands and feet, drawing all your blood to the surface where it can easily be dispersed. This improves our “temperature circadian rhythms,’ which helps us fall asleep more quickly and improves sleep quality. So, while you may be feeling toasty warm in the tub, you’re actually cooling your core body temperature after you get out. This signals your brain that it’s time to snooze.
Science says it’s so
There are 13 different studies in the Sleep Medicine Review that back this up. People not only report sleeping longer overall after a hot bath, but they also report better sleep quality. One study showed that as little as 10 minutes in 104-degree water 1-2 hours before bed reduced the time it took to doze off by nearly 9 minutes.
In addition, researchers combed through 5,322 individual studies as part of a meta-analysis on sleep. They analyzed the effects of “water-based passive body heating” (a fancy way to say taking a hot bath) on several key indicators of sleep quality:
- Sleep onset latency (how long it takes to fall asleep)
- Waking after sleep onset
- Total sleep time
- Sleep efficiency
- Slow-wave sleep (REM and deep sleep, critical for memory and brain function)
- Sleep efficiency
The results proved that a warm bath makes a huge difference in your overall sleep quality, with the best time for doing so being 1-2 hours before going to bed. And the meta-analysis confirmed that the bath need not be longer than 10 minutes in order to reap the benefits.
I didn’t know the science behind all of this until we did this research; I just knew that it worked. If I get in my hot tub just an hour before I head to bed, I have the best night’s sleep. For those of you that take a while to get to sleep at night, or have trouble staying asleep, try a hot bath and see if it helps.
An important note: Do you rely on Ambien to sleep? Read this
A recent study on zolpidem (known by its brand name, Ambien), showed that patients who used zolpidem fell asleep about 16 minutes faster than the placebo group. That’s only seven minutes faster than people who took a warm bath prior to bed, without the risk of chemical dependence. (Note: I was going to include the list of side effects for this medication in this post until I saw that there was a full two pages of them listed on the medication’s official website! Yikes!)
If you’re someone who relies on medicine in order to fall asleep, why not try taking a hot bath 1-2 hours before bedtime? It’s certainly a much safer choice.
Benefit #5: Hot baths burn calories and improve blood sugar
Another benefit you might be interested in is the research that shows hot baths can burn calories and reduce blood sugar response to food. Once again we’re not all about weight loss here at More Than Healthy, but when something as simple as a hot bath can burn calories, we’re going to talk about it!
In a study conducted at Loughborough University, they investigated the effects of hot baths on blood sugar control and number of calories burned. Participants were assigned either an hour-long soak (in water at 104 degrees) or an hour of cycling. They were attempting to raise core body temperature by 2-3 degrees over the course of an hour.
The cycling resulted in more calories burned compared to the hot bath, but the bathing showed about as many calories being burned as a half-hour walk (around 140 calories). The overall blood sugar response to both conditions was similar, but peak blood sugar after eating was actually about 10% lower in the participants that took a hot bath compared to those that exercised. Would you rather soak in a hot tub for an hour? Or cycle for an hour? I think those results are really compelling!
Why it works
Studies with animals may have identified how heating has this effect on us. They suggest that one of the key regulators of blood sugar control may be something called heat shock proteins. Heat shock proteins are molecules that are made by all cells of the human body in response to stress. Their levels rise following exercise and passive heating, such as soaking in a tub. Raised levels of these proteins may help the function of insulin and improve blood sugar control, which explains why a hot bath affects calorie burn and blood sugar control.
Hot baths, exercise, and inflammation
An additional health benefit of hot baths is how it affects inflammation. We’ve already talked a lot about the health problems associated with chronic inflammation. Inflammation is linked to illness and pain. Chronic inflammation reduces your ability to fight disease. One of the reasons exercise is so good for us is that it creates an anti-inflammatory response in our bodies. This helps protect us against infection and illness. Studies found that hot baths produce an anti-inflammatory response in our bodies that is similar to what happens following exercise.
How to best get the health benefits of hot baths
So how long and how often should you take a hot bath? Just like everything else here at More Than Healthy, we’re going to say you need to figure out what works best for you. Most recommendations say to start with 3-4 times a week for at least 20 minutes in 100-degree water. Then you can work up to longer, maybe even 104-degree water, and a little more often. Be sure to check with your doctor if you have any health issues that would prevent you from doing this.
Hot baths keep you More Than Healthy
Are you a fan of taking hot baths? Or have you decided to become one now that you know the science behind the health benefits of hot baths? Let us know if you have any questions or concerns about the health benefits of hot baths. We’d love to talk with you more about it!
For those of you interested in our free More Than Healthy coaching calls, we do them once a month on a Tuesday night at 6 PM MST. In fact, our next one is tomorrow night. We’ll be discussing everything we’ve discussed this month, including the health benefits of laughter, the right kind of salt, and keeping the promise. It’s bound to be a great discussion! Anyone can join us. Just text COACHING to 1-647-558-9895 to join our email list or watch our social media pages and we will have the link there.
Thanks for joining us! See you next week.