Why do the Japanese drink hot water? An exploration of tradition and wellness

October 31, 2025 •

4 min read

Based on research from the World Health Organization, Japan boasts one of the highest life expectancies globally. Many attribute their longevity to various health practices, including the question of why do the Japanese drink hot water as part of their daily routine. This seemingly simple habit is steeped in cultural wisdom and a holistic approach to well-being.

Quick Summary

The Japanese practice of drinking warm water, known as sayu, is deeply rooted in cultural tradition and a wellness philosophy focused on maintaining internal balance. It is believed to aid digestion, support detoxification, and promote overall well-being, rather than serving as a miraculous cure for specific ailments.

Key Points

Mindful Ritual: The Japanese practice of drinking hot water, or sayu, is a meditative act of wellness, promoting internal balance and connection to cultural traditions.
Digestive Support: Warm water is believed to aid digestion by relaxing muscles and assisting in the breakdown of fats, especially when consumed during or after meals.
Body Detoxification: Drinking hot water, particularly in the morning, is thought to stimulate circulation and flush out toxins, supporting the liver and kidneys.
Supports Circulation: The warmth dilates blood vessels, which improves blood flow throughout the body and can offer relief from poor circulation.
Efficient Hydration: Some believe warm water is more effectively absorbed by the body than cold water, enhancing hydration.
Traditional Beliefs vs. Modern Science: The practice is rooted in traditional medicine like Kampo, and while modern science validates hydration benefits, extreme curative claims are unproven.
Simplicity and Consistency: Incorporating this simple habit consistently throughout the day, such as upon waking, is key to its perceived long-term wellness effects.

The Cultural Roots of Drinking Hot Water

For many in Japan, drinking hot water is not merely about hydration; it is a mindful, purposeful ritual. This practice, often referred to as sayu (plain hot water) or shirayu (pure hot water), has a long history intertwined with traditional Japanese and East Asian medical philosophies. These traditions, which include Kampo (traditional Japanese medicine), emphasize the body's internal harmony and the belief that extreme temperatures, whether in food or drink, can disrupt this balance.

The Concept of Sayu and Mindfulness

The ritual of preparing and drinking sayu encourages a moment of stillness and mindfulness in a fast-paced world. It provides an opportunity to pause, focus on the body, and connect with a simple, ancient wisdom. This aligns with broader Japanese cultural values of simplicity, self-control, and prevention over cure, all of which are linked to their renowned longevity. Unlike sugary or caffeinated drinks, hot water is a pure and simple way to hydrate mindfully.

The Claimed Health Benefits: From Digestion to Detox

While sensationalist claims often circulate online, the core belief in Japan is that warm water offers a gentle, natural way to support the body's functions. The benefits are considered subtle and long-term, rather than instantaneous.

Aiding Digestive Health

One of the most widely cited reasons is the positive effect on the digestive system. In contrast to cold water, which proponents believe can constrict blood vessels and potentially slow down digestion, warm water is thought to:

Relax the muscles of the digestive tract, aiding smooth passage of food.
Help dissolve fats from food, making them easier for the body to metabolize.
Stimulate circulation in the stomach and intestines, optimizing the digestive process.
Warm water on an empty stomach in the morning is a common ritual to 'wake up' the digestive system.

Natural Detoxification

Advocates of the practice believe that drinking warm water supports the body's natural detoxification processes. By stimulating the lymphatic system and blood circulation, it is thought to help flush out toxins that accumulate overnight. This is seen as a way to support the function of the kidneys and liver, the body's essential filtering organs. This ritualistic cleansing is believed to contribute to clearer skin and a feeling of refreshment.

Improved Blood Circulation

Improved circulation is another benefit linked to warm water consumption. The warmth can help dilate blood vessels, promoting better blood flow throughout the body. For those who experience poor circulation or have cold hands and feet, particularly in Japan's colder climates, this can be particularly beneficial.

Hot vs. Cold Water: A Traditional Perspective

Japanese tradition, and Eastern medicine more broadly, often view cold water as a shock to the system, while Western cultures frequently prefer it for its refreshing qualities. The table below compares the perspectives.


Aspect	Traditional Japanese Perspective	Common Western Perspective
Effect on Digestion	Warmth relaxes muscles and aids in dissolving fats, promoting smooth digestion.	Cold water is often seen as harmless, though some proponents suggest it can slow metabolism temporarily.
Energy Balance	Maintains internal harmony (Ki/Qi), preventing the body from being 'shocked' by extreme temperatures.	Temperature is primarily a matter of preference for taste and refreshment.
Hydration	More efficient, as the water is closer to body temperature and is absorbed more easily.	Cold water is often perceived as more thirst-quenching, especially after exercise.
Metabolism	Drinking warm water may slightly increase body temperature, leading to a temporary metabolic boost.	The effect of water temperature on metabolism is generally considered minor in scientific discourse.
Experience	A calming, mindful ritual that provides comfort and tranquility.	A utilitarian action to quench thirst and cool the body.

Modern Perspectives and Practical Integration

While traditional beliefs underpin the practice, some modern scientific analysis supports certain elements, particularly regarding adequate hydration and digestion. The key is to approach the practice with realistic expectations, viewing it as a supportive health habit rather than a miraculous cure.

How to Incorporate the Practice

Adding this simple ritual to your routine can be done easily:

Morning Ritual: Start your day with a glass of warm water on an empty stomach to gently stimulate your digestive system.
During Meals: Swap out cold beverages for a cup of warm water or tea, which can assist with digestion.
Evening Routine: A glass of warm water before bed can help relax the body and mind, promoting better sleep.
Mindful Moments: Instead of reaching for a coffee or sugary drink, pause and mindfully sip a cup of warm water.

Conclusion: More Than Just a Drink

Ultimately, why do the Japanese drink hot water is a question with a multi-layered answer, blending cultural heritage, mindful practices, and a preventative approach to health. While not a cure-all, this habit serves as a foundational element of Japanese wellness, supporting digestion, detoxification, and internal balance. It is a testament to the power of simplicity and ritual in nourishing both the body and the mind, contributing to the longevity and vitality for which the Japanese are so well known. The essence of the practice is less about a single outcome and more about the ongoing, mindful commitment to one's own well-being. For those interested in exploring the deeper context of this and other Japanese wellness philosophies, understanding principles like ikigai and shizen provides further insight into their balanced approach to life.

Scientific Context and Cautions

It is important to remember that while adequate hydration is crucial for health, drinking large quantities of water in a short period can lead to overhydration (hyponatremia), which is dangerous. As with any health practice, a balanced approach is best. Scientific evidence does not support claims that hot water can cure serious diseases like cancer or diabetes. Instead, it should be seen as a healthy, hydrating practice that complements a balanced diet and regular exercise.

More information on the science of hydration and its general benefits can be found at Healthline.

Frequently Asked Questions

Sayu is the Japanese term for plain hot water that has been boiled. It is a traditional drink central to Japanese wellness practices and is often consumed for its purported digestive and detoxification benefits.

From a traditional medicine perspective, many in Japan believe that cold water shocks the body's internal system and disrupts its natural balance. Warm or room-temperature water is preferred to maintain harmony and aid digestion more gently.

While some claim hot water therapy aids in weight loss by boosting metabolism and promoting fullness, scientific evidence is mixed. The practice's contribution is likely more about adequate hydration and replacing high-calorie drinks with calorie-free water.

Many of the specific and grand claims associated with 'Japanese water therapy' (including curing cancer or diabetes) lack scientific evidence. The general health benefits of drinking sufficient water, however, are well-established.

Most practitioners suggest drinking water that is warm or lukewarm, around 50–60 degrees Celsius, rather than scalding hot. This temperature is intended to be soothing and gentle on the digestive system.

Begin by drinking a glass of warm water on an empty stomach every morning. You can also replace your usual cold drinks with warm water or herbal tea during meals. Consistency is considered more important than volume.

From a traditional perspective, yes, it is believed to assist the body's natural detoxification processes by stimulating blood circulation and supporting organ function. However, the body is naturally equipped for detoxification, and water is simply an important element of that process.

Yes, some variations include adding a slice of lemon for vitamin C and antioxidants or a piece of ginger for its anti-inflammatory properties, though the simplest form is plain hot water.