In a hot spring, joint stiffness, lower-back tightness, and muscle pain can sometimes feel easier. This is thought to happen mainly because the body warms up, the water makes the body feel lighter, and tension relaxes. However, feeling better is not the same as curing the cause of pain. A hot spring can support pain management, but it cannot replace medical care.

This article explains the mechanisms thought to ease pain in hot springs, how to tell which conditions are more suitable and which should be checked by a doctor first, and basic bathing guidelines based on public guidelines.

This article provides general information only and is not medical advice. If you have a chronic condition, severe pain, or pain with no clear cause, do not leave it to the hot spring alone. Please consult a doctor. If your doctor has given you bathing restrictions or treatment instructions, those come first.

Why hot springs may ease pain

The Ministry of the Environment groups the effects of hot springs on the body into three broad categories: thermal effects, where the heat of the water warms the body; physical effects, where water pressure and buoyancy act on the body; and chemical effects, where dissolved minerals work on the body. The sense that pain becomes easier is mainly explained by thermal and physical effects, along with the relaxation that is often easier to feel at a hot spring resort.

When the body warms up, tight muscles often loosen and people feel that blood flow improves. This thermal effect is especially helpful for chronic shoulder or back tightness and discomfort that worsens when you are cold. Even pain medicine specialists explain that heat can reduce pain, improve peripheral circulation, and make joints easier to move.

In the bath, water pressure and buoyancy also work. Because buoyancy supports part of your weight, the load on the joints is lighter than on land, so knees and lower back may feel easier to move. Since pain often feels worse with tension and anxiety, the quiet and relaxing environment itself can also help reduce distress.

That said, these are still explanations of what is thought to happen, and they do not work the same for everyone or in every hot spring. Chemical effects, or the influence of the spring water type, are discussed below, but in many cases temperature and bathing method matter more than the water type itself. For a broader look at hot spring health benefits, see Hot Spring Health Benefits and Scientific Evidence.

What it means that musculoskeletal symptoms are included in the approved conditions

Based on the Hot Springs Act, the Ministry of the Environment has set the "contraindications" and "indications" that hot spring facilities should display. Here, indications refer to conditions for which symptom improvement may be expected through hot spring therapy, and the 2014 revision reflects the latest medical knowledge at that time.

The general indications clearly include musculoskeletal symptoms. Specifically, they list "chronic pain or stiffness in muscles or joints," including the chronic stages of rheumatoid arthritis, osteoarthritis, lower back pain, neuralgia, frozen shoulder, bruises, and sprains, as well as "muscle stiffness in paralysis." In other words, there is public guidance behind the idea that hot springs are well suited to back pain and joint stiffness.

What matters is that indications do not mean the disease is cured by a hot spring. They are only a guideline showing that symptoms may be eased by effects such as heat. The conditions listed are chronic pain and stiffness. By contrast, acute stages with heat or strong inflammation are not included. This is the line: hot springs may help chronic tightness, but they are not suited to sudden worsening pain.

Conditions more suitable for hot springs, and those that should be checked by a doctor first

Hot springs are more suitable for chronic pain with stiffness or a feeling of cold. On the other hand, pain that suddenly becomes stronger, or pain with swelling, heat, or numbness, can worsen if it is warmed, and may also delay the diagnosis of a condition that needs treatment. The table below summarizes the difference in approach.

When pain appears, it is easy to think that warming is always best. But depending on the condition, warming may not be appropriate at all. In particular, right after an acute injury, or when a spot feels hot and swollen, the right response is to cool it, rest, and seek medical care. For the full picture of when it is safe to bathe, see Hot Spring Precautions: Dangerous Bathing Habits and Who Should Avoid Bathing.

Does the type of spring water make a big difference?

Certain spring water types are often discussed in relation to pain, but the visitor’s experience is not determined by mineral content alone. Water temperature, bathing time, keeping warm after bathing, and how tired you are that day all strongly affect how pain feels.

Some spring waters, such as chloride springs, feel especially warming after bathing and may suit coldness and stiffness well. On the other hand, acidic springs and other strong waters may be hard on the skin or body depending on your condition. The features of each spring type are covered in Hot Spring Water Types for Beginners, but for pain relief it is more realistic to focus less on the exact spring type and more on relaxing in a comfortable temperature.

Do not try to cure pain with hot springs alone

With chronic pain, there may be days when a hot spring makes you feel better, but that does not mean the cause is gone. Back pain and joint pain can stem from posture, lack of exercise, age-related changes, nerve problems, and many other factors, and heat only eases part of them. Even in medical settings, hot spring therapy is viewed as something that supports medication and rehabilitation, not something that replaces treatment.

What you should especially avoid is switching to hot springs alone because you want to stop pain medication. Hot springs can be useful as support, but do not change prescribed medication or treatment on your own. Decide with a doctor. Hot springs are best used together with exercise therapy, sleep, posture improvements, and medical visits or medication when needed. The tradition of staying at a hot spring resort for recovery, called toji, is also not a replacement for medicine; it is a way of spending time that helps organize daily life, and it is covered in What Is Toji?.

Basic bathing tips when you want to ease pain or stiffness

If your goal is to reduce pain or stiffness, it is better to warm up slowly at a comfortable temperature than to stay long in very hot water. Water that is too hot can cause overheating and strain, which may leave you feeling more tired and make the pain feel worse. As a rough guide:

• Keep the water from being too hot, aiming for 41°C or lower
• Do not soak for too long at once; aim for about 10 to 15 minutes and get out before you feel faint
• Do not cool your body suddenly after bathing; keep warm and preserve the heat
• Drink about one glass of water before and after bathing
• Do not force the painful area to move or massage it strongly

The safest approach is to leave before the feeling of comfort peaks, and only move stiff areas gently. For a more detailed look at bathing time and frequency, see How Long and How Often to Use Hot Springs.

People who need extra caution

People with severe high blood pressure or heart and respiratory disease, people with fever or strong inflammation, those right after an injury, and anyone who has been drinking alcohol should be careful with bathing regardless of whether they have pain. Trying to ease pain by soaking too long can add overheating, dehydration, and blood pressure changes, which puts stress on the body.

Older adults should also be careful because, in addition to pain making movement harder, there is a risk of dizziness and falls in the bath area. Rather than enduring the bath for too long, it is safer to keep it short, use handrails, and get out immediately if anything feels off.

FAQ

Can a hot spring cure lower back pain?

A hot spring may make lower-back tightness or stiffness feel easier, but that is only temporary relief from heat and buoyancy. It does not necessarily cure the cause of the pain. It can help as support for chronic lower-back tightness, but if the pain suddenly worsens or comes with numbness, see a doctor instead of just waiting it out in a hot spring.

Which spring water type is best for pain?

It is often said that temperature and bathing method matter more than the spring water type itself. Waters that feel especially warming, such as chloride springs, may suit coldness and stiffness, but no specific spring type can be said to remove pain by itself. Relaxing in a comfortable temperature is more realistic.

Can people with rheumatoid arthritis or osteoarthritis use hot springs?

The Ministry of the Environment’s general indications include chronic stiffness in rheumatoid arthritis and osteoarthritis. However, this guidance assumes the chronic stage. It is not suitable during active phases when joints are swollen and hot. If you are under treatment, ask your doctor whether bathing is appropriate and how to do it.

Should painful areas be warmed?

Pain with chronic stiffness or coldness may feel better when warmed, but that does not apply to every kind of pain. Right after an acute injury, or when an area is swollen or hot, warming may make things worse. In those cases, cooling, rest, and medical care come first.

How should I use hot springs together with pain medicine?

Hot springs may help ease pain as support, but they are not a replacement for medical care. Do not decide on your own to swap pain medicine for hot springs. Ask a doctor or pharmacist how to use your medicine. It is safest to think of hot springs as something used alongside daily care and treatment.

Summary

Hot springs may feel like they ease pain because thermal effects, water pressure and buoyancy, and relaxation all work together. The Ministry of the Environment’s general indications also include chronic pain and stiffness such as rheumatoid arthritis, osteoarthritis, lower back pain, neuralgia, and frozen shoulder, so hot springs are more suitable for chronic stiffness and coldness.

At the same time, indications do not mean a condition is cured. A hot spring is only a support for pain management. If pain suddenly becomes stronger, or if there is swelling, heat, or numbness, it is better to seek medical care rather than wait and see in a hot spring. A practical way to use hot springs is to bathe in water that is not too hot for about 10 to 15 minutes, get out before overheating, keep warm, drink enough water, and combine bathing with needed medical care and daily self-care.

Sources

• Ministry of the Environment, "Protection and Use of Hot Springs" notifications and guidelines related to the Hot Springs Act (contraindications, indications, and bathing precautions)
• Ministry of the Environment, Director-General of the Nature Conservation Bureau notice: "Standards for posting contraindications and precautions for bathing or drinking based on Article 18, Paragraph 1 of the Hot Springs Act" (July 1, 2014)
• Ministry of the Environment, "Guidelines for the Analysis of Mineral Springs" (2014 revision)
• Ministry of the Environment (supervised by the Japan Balneology, Climatology and Physical Medicine Association), "The Basics of Safe and Secure Hot Spring Use"
• Hamamatsu Medical Center, Rheumatology Department, "A Guide to Hot Spring Therapy for Relieving Body Pain and Stiffness"