The native guide; All about unique Japan, pub-5441866818918003, DIRECT, f08c47fec0942fa0 Japanese Hot Spring "Onsen" Effects; Health Benefits And Risks | Japanmcconnell

Japanese Hot Spring “Onsen” Effects; Health Benefits And Risks

Japanese hot springs health benefit and risk Japanese Wellness

As a Japanese lifestyle from ancient years, daily bathing at home and visiting hot springs annually are essential rituals to heal our bodies and minds.

Not only the Japanese but also Europeans have believed in the therapeutic power of hot springs, and they have used it for thousands of years as a natural therapy treatment.

Have you ever heard “balneology” or “balneotherapy”???

Which is the study of therapeutic bathing and medicinal springs, so many scientists from Japan and European countries have long been studying how hot springs bring health benefits.

Indeed, there are several therapeutic benefits of the hot spring such as stimulating nerve systems.

The Japanese often call the therapeutic power of hot springs the hot spring “Onsen” effect, the Japanese expect the same effects using Japanese bath salt products at home.

When using these Japanese bath salt products for your bath time, you can expect the same “Onsen” effects! Also, visiting Onsen towns in Japan maybe already one of your bucket lists in Japan travel.

So, what you can expect from bathing at home and in natural hot springs?

Like prescription & medication, there are always positive sides and negative sides.

Today, I am going to tell you the health benefits and risks caused by Japanese hot springs based on the Japanese bathing rituals.

Natural Hot Springs In Japan; Health Benefits

Natural hot spring water contains various minerals and effective ingredients that promote hormone secretion in the human body.

To penetrate minerals and effective ingredients in hot spring water in the body lead to boost blood circulation, relieve the tension of muscles and joints, and treat skin conditions.

In this section, let’s talk about these 4 main Onsen effects.

  1. Boost Blood Circulation
  2. Reduce Stress
  3. Promote Detox
  4. Improve Skin Condition

Boost Blood Circulation

the thermal effect, joint pain

As the body warms in the hot tub, blood vessels will be expanded and boost blood flow which improves metabolism. In other effects, improved blood circulation suppresses nerve hypersensitivity, and can be expected to relieve chronic pains and tensions.

Bathing has the massage effect by the water pressure promotes blood circulation and removes fatigue and swelling of the legs.

It is also said to exert effects on the heart and blood vessels, such as lowering blood pressure.

Reduce Stress

thermal effect, hot springs, spa

Due to buoyancy works, you feel the body lighter which expects a relaxing effect and relieves muscle tension.

Particularly, 37 to 40 Celsius (98.6 – 104 F) hot water stimulates the parasympathetic nervous system, which helps to slow your heart rate and be relaxed.

When you visit a hot spring town in Japan, you can be relaxed from nature, people, and other aesthetics. Besides, the Onsen effects provide a comprehensive stimulus that enhances the natural healing power in the human body.

At home, you can also enhance the relaxing effect with your favorite scents such as using essential oils and candles.

Taking a bath in hot springs and at home 2 hours before sleep brings better sleep immediately after going to bed.

On the other hand, hot water at over 42 Celsius (109F) hot water stimulates the sympathetic nerves and brings a refreshing feeling.

However, hot water above 42 Celsius (109F) causes dry skin and also high blood pressure, so complete bathing for 10 minutes with a half-body bath method. If you have high blood pressure or heart disease, better avoid taking a hot bath at 42 Celsius (109F) and higher.

Promote Detox

As I said, when the body warms in the hot tub, blood circulation will be boosted and then improve metabolism, discharging waste and toxic substances from the body which leads to relieving fatigue and swelling. (Detoxify)

Especially bathing in a hot spring and hot bath added bath salts is believed to have the same effect of them, effective ingredients in the water penetrate the body through the skin and breathing, improving blood circulation and raising the body heat.

When your body temperature is higher, the better your metabolism is.
Moreover, the hot spring ingredients remain on the skin even after bathing and the effect continues.

Warm the body→ Boost blood circulation→Rise the body temperature→ Boost Metabolism→ Improve Detoxify→ Keep the body warm→ Improve basal metabolism

Therefore, it is better not to rinse your body after bathing in a hot spring.

Moreover, many natural hot springs in Japan contain “Magnesium” which impacts metabolism a lot.

Magnesium penetrated through the skin combines with waste and toxic substances in the blood and is discharged. Therefore, in addition to the warm bath Onsen effect, you can expect the effects of further detoxification and metabolism improvement.

Magnesium is known as one of the minerals in seawater, and it has been considered the essential element for Thalassotherapy.

By the way, we can’t make Tofu without Magnesium.

Treat And Improve The Skin Condition

Japan is home to natural hot springs- there are thousands of hot springs and are categorized into 10 types by water properties and their effects. As one of the Onsen effects is considered to help skin treatment. Today, to use hot spring benefits as medical treatment, much research has been undergoing.

For example, Alkaline hot springs are expected to dissolve sebum and soften the stratum corneum -a cleansing effect leads to smooth and beautiful skin.

Acidic hot springs have bactericidal and antibacterial effects, which are good for skin irritations and infections such as heat rashes and eczema.

It has also a natural peeling effect for softening and dissolves old calluses on the surface of the skin.

If you have sensitive or dry skin, please be careful about these hot springs and bath salt products that have a skin treatment effect. Especially in alkaline hot springs, a lot of oil may be removed from the skin. Rinse well after bathing and apply moisturizers. Do not rub your skin too much with a towel.

Safety Tips For Preventing Negative Effects And Accidents Of Bathing

I talked about the positive benefits of bathing in hot springs,
it can lead to life-threatening accidents if you don’t know the negative sides.

To enjoy hot springs and a hot bath at home, learn the proper bath tips below.

Check Your Symptoms

The efficacy of natural hot springs has a positive effect on health as you read, but if you are not in the best condition, the Onsen effect can work negatively.

If you have any of the following symptoms, refrain from using hot springs until you are completely cured.

  • Fever
  • Severe high blood pressure
  • Severe heart disease or kidney disease
  • Severe diabetes
  • Rheumatoid arthritis
  • Early and late pregnancy, nursing, predisposition to bleeding, menstruation
  • Sensitive skin or severe skin conditions
  • Over 50 and have abnormal or anxious blood pressure or heart.
  • Elderly people and those with dry skin, avoid bathing in sulfur springs or hydrogen sulfide springs

*sulfur springs generally smell like rotten eggs and the color is emerald green or milky white. Famous sulfur springs in Japan are Takayu Onsen, Manza Onsen, Tsukioka Onsen. (Wikipedia).

Before And After Meals

When you are hungry, your blood sugar level is lower than in normal conditions.

Bathing is consumed energy more than you think, and it can cause hypoglycemia.

Eat something light in advance.

But, you should avoid soaking in the hot tub right after a meal. Improved blood circulation due to the bathing effect impacts gastrointestinal blood circulation negatively and stops gastric juice secretion and gastrointestinal motility.

It is the one of reasons you should wait to bathe after you drink alcoholic beverages.

Therefore, you should avoid bathing under hunger, and eat snacks. But wait for at least 1 hour after a heavy meal and drinking alcohol.

The Importance Of “Ka Ke Yu”; Adjust Your Body To The Water Temperature


“Kakeyu”(かけ湯) literally means rinse the body scooping the water in the bathtub with a tiny bucket before entering a hot bath.

I talk about Kakeyu in a good manner (as cleaning your body) on this page,  but also it is an important tip to adjust the body to the temperature of a hot spring.

Kake-yu is an important ritual to let the body adjusts the water temperature before soaking in the hot water. If you take a bath without Kake-yu, your blood pressure will rise suddenly. Especially for those who usually have high blood pressure, are diabetics, and weakened blood vessels, this is a very dangerous habit at leads to cerebral hemorrhage.

When doing Kake-yu, be sure to rinse your feet. Rinsing your shoulders at first burdens your heart which can cause paralysis. At public hot springs, doing Kake-yu in a sit position, not standing to avoid splashing the water on other people.

At home, you can use the shower.
From the limbs to the upper body, go for 30 seconds or more with hot water at 41 ° C.

Use A Half-Body Bath Method

Recently, the half-body bathing method is recognized as healthy bathing especially for older people, those who are worried about their health, and those who are pregnant, because it has less burden on the heart and can suppress sudden fluctuations in blood pressure.

Besides, the half-body bath promotes metabolism and detox.

At hot springs in Japan, there is commonly a step inside of tubs. First, sit on the step and bathe the half-body (up to the under chest) for 2-3 minutes and adjust your body to the water temperature.

If there is no step, step into the water thoughtfully and soak the half-body slowly. You can do the same steps at home.

Then, step forward into the water- put your head on the edges and stretch your limbs, and your body will float. This floating position is suitable for relieving water pressure and is more relaxing than soaking your body vertically in the bathtub.

Avoid Taking A Bath For A Long Time

take a rest

When you are cozy in the hot tub, it is likely to take a bath for a long period, but this can cause fatigue, dry skin, and bathing accidents in the worst case.

Repeat going in and out of the tub, rather than bathing for a long period at once.

If you are a beginner at bathing in a hot spring or at home, enjoy bathing for 5 – 10 minutes the first couple of times then take a bath for 30 minutes or less- avoid taking a bath for 30 minutes over.

Hot water around 109 F (42℃) and higher is not recommended for the purpose of relaxation and relief of pain and tension. If the water temperature is quite high at around 109 F (42℃), complete to bath for 10 minutes max.

Putting A Cold Towel On The Head


Put a folded cold towel on the head to prevent dizziness caused by a hot flush.

When staying in Ryokan or accommodations with hot springs, you will be provided a long thin cotton towel called “Tenugui”, and put on your head while bathing in the tub.

*Anyway, you will have trouble finding a place to put a towel in a public hot spring in Japan, and also it is taboo that soaks the towel in the bathtub. So you have no choice but to put it on the head.

While taking a bath, a pressure called “hydrostatic pressure” is applied to the body. Surprisingly, it’s a strong pressure, and it makes systemic blood concentrate on the head. It can cause a hot flash and lead to the feeling of dizziness in the worst case.

The cold wet towel on your head solves this worry! Place a wet towel to prevent a hot flash in the hot spring.

It is a similar logic that you may feel dizzy when getting out of the tub. This is because the lower body is released from hydrostatic pressure and blood that is concentrated in the head flows rapidly to the feet. You feel dizzy because the blood flow in the head decreases at once.

Keeping your head lower is a good way to get out of the bathtub. After bathing, apply cold water to your legs under the knees to constrict blood vessels throughout the body and prevent dizziness. People with high blood pressure should not do this, as this tip raises blood pressure.

Enjoy Open-Air Hot Springs After Indoor Hot Springs

If Ryokan you staying in has open-air hot springs and indoor hot springs, take the indoor bath first.
The most important thing to keep in mind when taking a bath is to take a hot bath while your body is cold suddenly.
Blood pressure rises rapidly – risks of stroke and myocardial infarction.

Please keep in mind, “If you have an indoor bath and an open-air bath, go to the indoor bath first.”

When you take an open-air bath, put a warm towel on your head instead of a cold towel. The lower body is warm but the shoulders and head are cold, resulting in poor blood flow in the head, which can lead to cerebral anemia and a rapid rise in blood pressure.

If you have a headache, you should finish the bath! To prevent these accidents, put a warm wet towel on your head to dilate the blood vessels. It is also effective to take a shower from the head before taking a bath.

*Again, soaking own towel in a public bath is taboo in Japan. Wet a towel outside of the tub.

Take A Enough Rest To Bath After Activities and Drinking Alcohol

During exercise, blood concentrates on the moving muscles to supply oxygen, and works to expel lactic acid(a waste substance) quickly. If you take a bath right after exercise, blood will be dispersed throughout the body and the metabolism of motor muscles will be insufficient. It will also increase the burden on the heart while taking a bath.

After exercising, take rest for 30 minutes or more after the respiratory rate and heart rate are stable.

When you drink alcohol and take a bath, the blood circulation in the body increase but the blood flow in the head decreases, which can cause cerebral anemia. Also, there are risks of arrhythmias and heart attacks as increasing heart rate.

It is even more dangerous if you are drunk because the bathroom is slippery and there is a risk of accidents such as falls and even drowning.

Not only you shouldn’t drink in the tub while bathing but also take rest for 1-2 hours before bathing when you have drinks.

Choose the Right Hot Spring Water For Skin

The Onsen effect helps to heal and improve skin conditions.

As I mentioned, Japanese hot springs are categorized into 10 types by water properties (including Ph level) and their effects.

In the Japanese hot spring association’s mandatory, the “Ph” measurement display must be indicated- acidity and alkalinity. If you have sensitive skin and severely dry skin, or skin disease, you should know the type of hot springs when choosing hot springs and also herbal bath salt products.

Do Not Rinse The Body, However…

Minerals dissolved in the hot spring water become a positive barrier for your skin, it is generally recommended to not rinse after bathing, however, rinse enough if you have sensitive skin, dry skin, and skin diseases.

Also, rinse the body well after bathing in water with strong acidity and alkalinity.


Does my post help you to learn about health benefits and risks when taking hot springs or at home???

The Onsen (hot springs) effects bring you many benefits with effective minerals and ingredients.

However, keep in your mind it can work negatively when you are unhealthy or planning bathing at unsuitable timing.

If you are not sure you can take a hot spring bath, better ask your doctor.

If you are interested in Japanese bath salt products you can experience Japanese Onsen at home,

Check out Japanese Bath salt products in this post!

Also, I give you Japanese bath tips to enhance the Onsen effect at home!

Hot Springs In Japan

In Japan, there are Japanese unique but complex hot springs etiquettes and manners you need to learn.

It’s a great experience to stay in Ryokan hotels to enjoy Onsen and Japanese traditional life at once. But you need to know the concept of staying Ryokan hotels to avoid controversy between different cultures.


Japanese Wellness
Sponsored Link
Sponsored Link
Don't forget click something to share with family & friends.
Sponsored Link
Sponsored Link
Sponsored Link
Copied title and URL