updated 7/04/08

A Better Hot Bath

Tips and tricks for getting the most out of the oldest form of therapy

by Paul Ingraham, Vancouver, Canada MORE
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Credentials and qualifications

I am a writer and retired Registered Massage Therapist (unusually well-trained for a massage therapist, a 3000-hour program). I’m almost done with a Bachelor of Health Sciences degree. I am a peer reviewer for The Natural Standard, and a copyeditor for Science-Based Medicine. My most important qualification is more than a decade of workaholic post-graduate study, clinical experience, and constant conversations with readers from around the world, including many experts who have provided countless suggestions and criticisms.

For more information, see: Who Am I to Say? More information about my qualifications, credentials and professional experiences for my readers and customers.

A hot bath is probably the original hydrotherapy treatment, and still the best. But as much as you may already enjoy a hot bath, there’s a good chance that you’re not tapping its full potential. At its best, a hot bath can be a surprisingly powerful tool for healing. But it’s easy to fall short of the maximum benefit. To get the most out of it, a little extra know-how is helpful.

Don’t make it too hot

A hot bath is psychologically relaxing. It was the original psychotherapy, and I suspect it is still the best.

Technically speaking, however, hot baths are a stimulant — that is, they get your nervous system revved up. The sensation of relaxation is an illusion in a number of ways. The ritual is safe and soothing. Strong heat tends to dominate your awareness, forcing out other thoughts. It also tends to make you stay still afterwards, while body temperature and other physiological conditions are restored to normal.

Technically speaking, hot baths are a stimulant — they get your nervous system revved up.

But your nervous system is actually stimulated. While a few people do get drowsy after a hot bath, many remain alert for at least an hour, and some will even have considerable difficulty sleeping for hours afterwards.

So the most relaxing baths are in not-quite-hot water. Most people I know still prefer a good hot soak for it’s other benefits — but if you are bathing for sedation or specifically to help you sleep, keep the temperature quite easy.

Note that pregnant women should keep their baths to a maximum of about 37˚C (100˚F) — just barely above body tempature!

Keep a cool head

Many people avoid hot baths because they feel wilted and cruddy and headachey afterwards. This can be avoided by keeping a cool head. Or feet. Or hands. Or all three.

As beneficial as it can be, your body doesn’t really love being heated up entirely, with no opportunity at all for heat shedding. This creates an artificial fever. An artificial fever has its uses (more below), but it can also have some unpleasant side effects, such as headaches.

So dump glasses of cool water over yourself! Or drape a cool washcloth over your neck. or spray your feet with a shower hose.

Give your body some opportunity to shed some heat. Your core body temperature will still go up (and you’ll get the benefits of that), but it will cause less physiological stress. You may be quite surprised at how much this improves the quality of the experience.

An artificial fever has its uses, but it can also have some unpleasant side effects.

Combine with massage

A bath is a perfect place to do a little self-massage to release muscular trigger points. And the perfect method is to bring a ball into the bath with you, and trap it under your body to apply pressure to stiff and aching muscles. I call this “the bath trick,” because it’s such an amazing combination of therapeutic factors. The bath trick works particularly well because the pressure you apply to your muscles is easy to control.

The Bath Trick

Run a hot bath, and trap a ball between your body and the bottom or back of the tub to rub your back muscles — your buoyancy allows for excellent control over moderate pressures.

In standard “tennis ball massage,” often people find that the full weight of their body trapping a tennis ball against the floor is simply too much — the pressure is too intense, and they’re unable to achieve a relieving sensation. But in the bath, you are much lighter! You have much better control and a moderate intensity of pressure.

While the heat relaxes you, your bouyancy in the water allows finely tuned control over moderate pressure on your trigger points. Applying a little more or less pressure is as simple as rising up in the water a little, or submerging more of yourself.

See The Bath Trick for Trigger Point Release for more detail.

Combine with stretch

Stretching is not generally as useful as most people imagine, but it’s certainly not useless. One of the things stretching may be fairly effective for is relieving muscular aches and pains caused by knots. Even that’s not exactly guaranteed to work miracles — lots of people fail to get rid of muscle knots just by stretching — but doing it in a bath almost certainly improves the odds of success.

Heat aids stretch in almost every way you can imagine. It reduces baseline muscle tone, it significantly softens connective tissue, it eases the neurological vicious cycle that powers muscle knots, and so on. If you’re going to stretch, then stretch in the bath.

Curious about the limitations of stretching I referred to above? See Quite a Stretch. Or for a detailed exploration of how muscle knots in particular are affected by stretching, see Stretching for Trigger Points.

Hydrate for enhanced elimination

You sweat under water. In a very hot bath, oddly enough, you can lose a lot of fluid.

Sweating is an important form of excretion, and many waste metabolites are removed from the body this way. Exercise is one way to do this, of course, but a hot bath is a lot easier — and, in fact, people usually sweat much more in a bath than they ever do when exercising.

Some people will call this “detoxification,” a word that gets thrown around too casually, usually to make something sound more therapeutic than it really is. A good sweat is a good thing, but it isn’t “detoxifying” any more (or any less) than having a bowel movement! It is more sensible to simply say that sweating stimulates elimination of waste products.

But sweating a lot in a bath also means that you must drink water — before, during and after! This is a vital key that most people miss. If you don’t hydrate, a hot bath may actually be stressful to your system — and I think this is why some people do not like baths. You must replace lost fluids to feel good later.

Drinking a lot of water is probably not as important as most people seem to think (see Water Fever and the Fear of Chronic Dehydration). However, when it comes to hot baths, you definitely do need to replace some lost fluids.

Baths for relieving muscle aching

Hot baths are probably quite effective for muscle soreness. This is surprisingly hard to prove, or even understand — it’s not exactly a hot target for research funding — but it’s pretty obvious to all of us that it works, at least a little. Here are some possible reasons why …

Covering yourself in hot water — “systemic” heating — can do something for muscles that no hot pack can ever do. As good as a nice hot pack can feel, the effect is a minor, local, neurological effect — warm skin relaxes the muscles underneath it. That’s a nice effect, but it’s limited. A hot bath also has this effect, but additionally it’s able to actually increase the temperature of the muscle itself deep heating.

Hot packs cannot heat the insides of your muscles.

Hot packs simply cannot increase the heat inside your muscles. The human body is incredibly good at temperature control, at getting rid of heat. When you try to heat a muscle with a hot pack, you end up heating just the superficial blood, which quickly gets pumped away and immediately cooled. It has been shown that local heating never “penetrates” much deeper into the tissue than a centimeter, and probably not even that much unless the heat is intense. The only really effective way to heat a specific muscle is by making it work, to produce heat from the inside out by burning metabolic fuel. But often this is not desirable in an injured or very fatigued muscle! So what to do? How to get the benefits of heating? The hot bath may work.

In a hot bath, excess heat has nowhere to go. The body cannot get rid of it, anywhere. The entire system heats up slightly — like a fever! It’s not a major effect, but it’s certainly much more than you can manage with a hot pack. And this is probably good for sore muscles in several ways.

Another common idea for bathing is that Epsom salts assist with detoxification and recovery from minor injuries, aches and pain. Do they?

Should you add Epsom salts?

That’s a big “maybe.”

Recent scientific evidence has shown that Epsom salts do indeed soak through the skin when you bathe in them1 — which is a bit surprising, and had never been proven before.

Unfortunately, there is literally no scientific evidence whatsoever about what happens after Epsom salts soak through the skin. Do they have any therapeutic effect? No one knows. It’s certainly possible. People certainly think there’s a therapeutic effect, but unfortunately that’s no way to judge the matter — people think all kinds of incorrect things!

For a full discussion of the subject, see Do Epsom Salts Work?.

Almost always use a hot bath for low back pain

A hot bath is not only a much better choice for the great majority of low back pain than icing — which is usually harmful — but soaking in the tub may simply be the single best therapy there is for low back pain, or at least the best bang for your buck! And yet many people actually avoid a hot bath when they have low back pain — tragically — because they think they are “inflamed” and the heat will make it worse. This is very rarely the case.

The great majority of low back pain is essentially muscular in nature, contrary to the popular and mistaken medical view that it’s usually caused by something “mechanical” like a intervertebral disc herniation.

Specifically, the cause of most back pain is myofascial trigger points (“knots” in your muscles), which can cause far more grief than most people realize — and yet they are relatively treatable. A little reassurance, rubbing, and a hot bath go a surprisingly long way, even with the most horrendous case of low back pain. hot bath is amazingly good therapy for back pain, and the price sure is right.

Once again, trigger points are eased by heat, and usually irritated by cold. For more information about why you shouldn’t ice low back pain, see (Almost) Never Use Ice on Low Back Pain!. For (much) more information about the nature of low back pain, see Save Yourself from Low Back Pain!.

One final tip: breathe!

To me, bathing is practically a religion. After years of “therapeutic bathing,” I am still experimenting.

One thing I’ve learned about bathing that I can’t really explain — something about temperature-induced changes in blood chemistry, perhaps — is that the experience is improved by slow, deep breathing. If you’re like me, you will be amazed how it extends your tolerance for the heat and enhances the relaxation. Conscious breathing is always relaxing and embodying, but it seems to be even more effective in a hot bath.

Notes

See Waring. Magnesium and sulfates in the blood were measured and found to be higher after people had Epsom salts baths. No therapeutic effects were studied or claimed. The results seem straightfoward. However, as of June 2008, it has not yet been peer-reviewed, published in a scientific journal or repeated by other scientists. Return to text.