Exiting the sauna and entering the cold plunge bath, the moment when the cold water envelops your entire body. The first 5 seconds are a shock, by 10 seconds you start to get used to it, and by 30 seconds it becomes comfortable. After leaving the cold plunge bath, the outdoor air bath brings the experience of 'totonou'.
In Japanese sauna culture, the cold plunge bath is one of the main attractions. Sauna, cold plunge bath, and outdoor air bath. Only when these three are combined does the perfect sauna experience occur.
This article will delve into the unique Japanese culture of cold plunge baths, covering temperature, water quality, effects, and the correct way to enter.
Why Are Cold Plunge Baths Emphasized in Japan?
Differences with Finland
Finnish Sauna
- Jump into lakes or snow after the sauna
- Use natural cold water
- Experience changes with the seasons
Japanese Sauna
- Cold plunge baths are permanently installed in facilities
- Temperature-controlled cold water
- The same experience year-round
Reasons for the Development of Cold Plunge Bath Culture in Japan
Fusion with Hot Spring Culture Japan has long had a culture of alternating between hot springs and cold water baths, known as 'contrast bathing'. Saunas have also merged with this culture.
Development of Urban Saunas Japanese saunas are often located in buildings in urban areas. Due to the lack of natural lakes or rivers, artificial cold plunge baths have developed.
Commitment to Quality The Japanese commitment to quality has elevated the temperature, water quality, and cleanliness of cold plunge baths to the utmost level.
Cold Plunge Bath Temperature: Differences in Sensation
Classification by Temperature
Extremely Cold (Below 10°C)
- Sensation: Extremely cold, for advanced users
- Effect: Strongest stimulation, maximum blood vessel constriction
- Caution: Strain on the heart, dangerous for prolonged periods
Cold (10–14°C)
- Sensation: Quite cold, requires acclimation
- Effect: Strong stimulation, deep 'totonou'
- Recommendation: Sauna enthusiasts
Standard (15–17°C)
- Sensation: Cold but bearable
- Effect: Moderate stimulation, most balanced
- Recommendation: Intermediate users and above
Slightly Cold (18–20°C)
- Sensation: Feels cold
- Effect: Mild stimulation
- Recommendation: Beginners
Lukewarm (Above 21°C)
- Sensation: Not very cold
- Effect: Weak stimulation
- Evaluation: Unsatisfactory for sauna enthusiasts
Ideal Cold Plunge Bath Temperature
Many sauna enthusiasts consider 15–17°C to be ideal. This temperature range:
- Is sufficiently cold
- But not too cold to enter
- Allows the most noticeable 'totonou'
Importance of Cold Plunge Bath Water Quality
Types of Water Quality
Tap Water
- Characteristics: Most common
- Disinfection: Chlorine
- Sensation: Normal
Groundwater
- Characteristics: Natural water drawn from underground
- Disinfection: Minimal
- Sensation: Soft, pleasant to the touch
Natural Water (Spring Water)
- Characteristics: Natural spring water
- Disinfection: Almost none
- Sensation: Premium, mellow
Softened Water
- Characteristics: Water with reduced hardness
- Disinfection: Chlorine
- Sensation: Soft to the touch
What is a 'Drinkable Cold Plunge Bath'?
Some sauna facilities in Japan boast 'drinkable cold plunge baths'.
Conditions
- Use natural groundwater or spring water
- Only minimal treatment
- Pass water quality tests
- Constantly refreshed (always new water)
Characteristics
- Astonishingly soft to the touch
- No chlorine smell
- Can stay in for a long time
- Gentle on the skin
Famous 'Drinkable Cold Plunge Bath' Facilities
- Considered 'sacred' among sauna enthusiasts
- Worth visiting from afar
- Unforgettable once experienced
Impact of Water Quality on 'Totonou'
High-quality cold plunge baths:
- Cause less skin irritation
- Allow longer stays
- Enable a deeper 'totonou' experience
- Make you want to return
Correct Way to Enter a Cold Plunge Bath
Step 1: Rinse Off Sweat (Most Important!)
Must-Do Before entering the cold plunge bath, always rinse off sweat. This is an absolute etiquette.
Method
- Exit the sauna
- Rinse off sweat with a shower or water
- Wipe sweat off with your hands
Why is it important?
- Hygienic: Consideration for others
- Water quality protection: Keep the cold plunge bath clean
- Effectiveness: Sweat makes it harder to cool down
Step 2: Pour Water Starting from Parts Far from the Heart
Order
- Pour water on feet
- Pour water on hands
- Pour water on arms
- Pour water on legs
- Pour water on body
This order gradually acclimates the body to the cold water.
Step 3: Enter Slowly
How to Enter
- Descend the steps (or slowly put your feet in)
- Submerge up to the knees
- Submerge up to the waist
- Submerge up to the shoulders
Caution
- Do not jump in (dangerous)
- Enter slowly (minimize shock to the body)
- Regulate your breathing
Step 4: Stay Still
During Bathing
- Stay still without moving
- Breathe deeply and slowly
- Close your eyes and relax
Body Changes
- First 10 seconds: Extremely cold, shocking
- 10–20 seconds: A thin film forms around the body
- After 20 seconds: Start to feel slightly warm
The 'water film' that forms around the body acts as insulation, making you feel slightly warm.
Step 5: Exit at the Appropriate Time
Time Guidelines
- Beginners: 30 seconds to 1 minute
- Acclimated individuals: 1 to 2 minutes
- Advanced users: 2 to 3 minutes
When to Exit
- When you feel sufficiently cooled
- Before feeling too cold
- Do not overextend yourself
Step 6: Exit Slowly
How to Exit
- Stand up slowly
- Climb the steps
- Lightly towel off
- Proceed immediately to the outdoor air bath
Gradual Approach for Those Who Dislike Cold Plunge Baths
Level 1: Just the Feet
Start by immersing only your feet in the water.
Method
- Sit on the edge of the cold plunge bath
- Immerse only below the knees
- 1 to 2 minutes
Level 2: Sit and Submerge to the Waist
Method
- Sit on the steps of the cold plunge bath
- Submerge to the waist
- 2 to 3 minutes
Level 3: Full Body for a Short Time
Method
- Submerge the entire body
- But only for 30 seconds
- Gradually extend the time as you get used to it
Level 4: Regular Bathing
Method
- Full body for 1 to 2 minutes
- If you can do this, you've succeeded!
Tips
Breathing is Key
- Continue deep breathing
- Inhale through the nose, exhale through the mouth
- Focusing on breathing makes the cold less noticeable
Gradual Progression Do not overdo it. Extend the time little by little each time.
Avoid Warm Showers Do not take a warm shower immediately if it feels too cold. Warm up with an outdoor air bath.
Health Benefits of Cold Plunge Baths
1. Promotes Blood Circulation
Mechanism
- Blood vessels dilate in the sauna
- Blood vessels constrict in the cold plunge bath
- Blood vessels dilate again during the outdoor air bath
This cycle of dilation and constriction greatly promotes blood circulation.
2. Regulates Autonomic Nervous System
Sympathetic and Parasympathetic Nervous Systems
- Sauna: Sympathetic dominance (excitation)
- Cold plunge bath: Peak sympathetic activity
- Outdoor air bath: Switch to parasympathetic (relaxation)
This switching balances the autonomic nervous system.
3. Boosts Immunity
The warm-cold stimulation activates the immune system.
4. Aids in Fatigue Recovery
Promotes the elimination of fatigue substances through improved circulation.
5. Relieves Stress
Adaptation to cold water enhances stress resistance.
Cold Plunge Bath Etiquette
Basic Rules
- Always rinse off sweat: Most important
- Enter quietly: Do not jump in
- Do not submerge your head: No floating hair
- Do not monopolize for long: Be considerate during busy times
- Do not contaminate the water: Keep it clean
About Hair
Long Hair
- Always tie it up
- Floating hair in the cold plunge bath is a no-go
Shampoo Suds
- Rinse thoroughly before entering
How to Find Facilities with Notable Cold Plunge Baths
Checkpoints
Water Quality
- Whether using groundwater or natural water
- Whether it is a constantly refreshed or circulating system
- Whether it is advertised as a 'drinkable cold plunge bath'
Temperature
- 15–17°C is ideal
- Check the thermometer
Cleanliness
- Is the water clear?
- Is the chlorine smell not too strong?
Depth
- Deeper is better (can submerge up to the shoulders)
Information Sources
- Sauna-specific review sites
- Posts by sauna enthusiasts on social media
- Apps like 'Sauna Ikitai'
Winter Cold Plunge Baths: The Ultimate Experience
Characteristics of Winter Cold Plunge Baths
Water temperature drops A cold plunge bath at 18°C in summer can drop to 14°C in winter.
Difference in outdoor temperature With an outdoor temperature of 0°C and a cold plunge bath at 15°C, the cold plunge bath is actually warmer!
Deep 'totonou' The combination of a winter cold plunge bath and a cold outdoor air bath creates the deepest 'totonou'.
Conclusion: Cold Plunge Baths are the Treasure of Japanese Sauna Culture
Cold plunge baths are an indispensable element of Japanese sauna culture. Warming up in the sauna, cooling down in the cold plunge bath, and 'totonou' in the outdoor air bath. This perfect three-step process is the essence of Japanese sauna culture.
It may be intimidating at first. It may be too cold to enter. However, once you experience the comfort of a cold plunge bath, there's no turning back.
A high-quality cold plunge bath feels like being wrapped in natural silk. Soft, gentle, and deeply relaxing.
When you visit Japan, be sure to experience a cold plunge bath. Step into the world of 'totonou'.
The cold plunge bath is the soul of the sauna.
