Nutrition Diet: Why should we not drink hot water and cold water together?

October 13, 2025 •

4 min read

According to the principles of Ayurveda, mixing hot and cold water creates a state of 'viruddh ahar' or incompatible food, which is said to confuse your digestive system. This traditional wellness belief is one of the key reasons why should we not drink hot water and cold water together, highlighting potential health implications often overlooked in modern diets.

Quick Summary

This article explores the health perspectives surrounding the consumption of beverages with contrasting temperatures. It discusses traditional wellness beliefs from Ayurveda, potential dental risks, and impacts on digestive function and hygiene.

Key Points

Ayurvedic Harmony: Ayurveda considers mixing hot and cold water to be 'viruddh ahar', or incompatible food, which impairs digestion and weakens the digestive fire ('agni').
Dental Risks: Rapid temperature changes from alternating between hot and cold drinks can cause thermal shock to tooth enamel, potentially leading to microscopic cracks and increased sensitivity.
Digestive Confusion: Introducing contrasting temperatures can send confusing signals to your digestive system, disrupting the normal rhythm and potentially leading to discomfort, bloating, or inefficient nutrient absorption.
Hygiene Concerns: Mixing purified boiled water with unboiled cold water can reintroduce germs and compromise the safety of the drinking water.
Gastric Motility: Scientific studies indicate that extreme temperatures can affect gastric emptying and contractions, with some evidence suggesting that extreme temperatures can slow down the digestive process.
Balanced Approach: Instead of mixing, it's advisable to drink water at a consistent, moderate temperature, such as room temperature or warm, to avoid shocking the body and to support better digestion.

Conflicting Signals for the Digestive System

The practice of mixing liquids with drastically different temperatures is advised against by some traditional health systems, most notably Ayurveda, due to its potential impact on digestion. Modern physiological understanding also offers some insight into how extreme temperatures can affect the digestive process. When you consume a very hot liquid, it stimulates and speeds up certain metabolic processes, while a very cold liquid has the opposite effect, constricting blood vessels and slowing things down. Introducing both extremes in rapid succession, or mixing them, sends conflicting signals to your body. This can disrupt the normal rhythm of digestion, leading to potential issues like bloating, discomfort, and less efficient nutrient absorption. Some scientific studies, for instance, have shown that liquids at extreme temperatures can influence gastric motility and the rate at which the stomach empties its contents, further complicating the digestive process.

The Ayurvedic Perspective: Weakened 'Agni'

Central to Ayurveda, the ancient Indian system of medicine, is the concept of 'agni', or the digestive fire. A strong agni is essential for efficient digestion and good health. From this perspective, hot water is considered 'light' and beneficial for digestion, helping to stimulate and cleanse the system. Cold water, on the other hand, is considered 'heavy' and dampening to the agni, slowing down the digestive process. By mixing these two opposing elements, you essentially neutralize their benefits and confuse your body's innate wisdom. This leads to a weakened agni and can cause digestive issues. For this reason, Ayurveda recommends consuming water at room temperature or slightly warm, and always avoiding ice-cold beverages, especially with meals.

Potential Risks for Dental Health

Beyond digestion, the rapid and significant temperature change caused by consuming hot and cold liquids together poses a risk to your dental health. Your teeth and their restorations, such as fillings, are sensitive to thermal changes. Tooth enamel expands and contracts at a different rate than the underlying dentin. Repeatedly exposing them to a thermal shock from alternating hot and cold can create microscopic cracks in the enamel over time. This can lead to increased tooth sensitivity and, in some cases, may even cause fillings to dislodge or teeth to crack.

The Overlooked Hygiene Factor

While this reason is less about the effect on the body and more about the quality of the water itself, it's a significant factor in some parts of the world. Many people boil water to kill harmful microorganisms and make it safe for consumption. If this boiled (and thus purified) water is then mixed with unboiled cold water, any potential contaminants from the cold water can be reintroduced, compromising the safety of the entire drink. This is an especially important consideration in regions where water quality is a concern. Even if you don't live in such a region, it's a practice that highlights the potential for contamination.

Mindful Hydration Habits

For optimal health and digestion, consider these mindful hydration tips:

Drink at Room Temperature: Opt for water at room temperature or slightly warm. This is less jarring for your digestive system and aligns with Ayurvedic recommendations.
Hydrate Throughout the Day: Instead of gulping large amounts of water at once, sip steadily throughout the day.
Time Your Intake: Avoid drinking large quantities of any liquid, regardless of temperature, immediately before or after a meal, as this can dilute digestive enzymes.
Cool Naturally: If you have boiled water, let it cool to room temperature naturally before consuming. Do not rush the process by adding unboiled cold water.
Listen to Your Body: Pay attention to how your body reacts to different water temperatures and adjust your habits accordingly. Some individuals may experience more sensitivity to temperature changes than others.

Comparison: Hot vs. Cold Water on the Body


Feature	Hot Water	Cold Water	Mixed Hot and Cold Water
Digestive Impact (Ayurveda)	Considered 'light', aids digestion and stimulates agni.	Considered 'heavy', dampens agni and slows digestion.	Confuses the digestive system, weakening agni and leading to inefficiency.
Digestive Impact (Physiology)	Stimulates blood flow and can potentially speed up certain metabolic functions.	Constricts blood vessels, slows digestion, and can affect gastric motility.	Sends conflicting signals to the digestive system, potentially leading to discomfort.
Dental Impact	Can increase sensitivity over time with repeated exposure, but less jarring than rapid changes.	Can increase sensitivity, especially for pre-existing conditions.	Causes thermal shock, which can lead to micro-cracks in enamel and stress restorations.
Sensation	Soothing and relaxing, often used for comfort and to aid in detoxification.	Refreshing and cooling, especially in warm climates.	Conflicting sensations that may cause discomfort in some sensitive individuals.
Traditional Views (General)	Often praised for health benefits, such as detoxification and promoting circulation.	Often advised against, particularly around meals, due to digestive impact.	Strongly discouraged in traditional systems like Ayurveda due to incompatible properties.

Conclusion: Navigating Traditional Wisdom and Modern Health

While drinking a single mixed glass of hot and cold water may not cause immediate harm for most healthy individuals, the cumulative effects and underlying principles are worth considering. The wisdom of traditional systems like Ayurveda provides a compelling argument against the practice, citing digestive confusion and the weakening of metabolic fire. Furthermore, the potential long-term impact on dental health from thermal shock is a valid concern supported by dental science. For those who boil their water for purification, the hygiene risk of reintroducing pathogens is a practical and important consideration. Ultimately, adopting a mindful approach to hydration—opting for water at a consistent, moderate temperature—is a simple change that can support better digestion, dental health, and overall wellness. By understanding why should we not drink hot water and cold water together, we can make more informed choices for our daily health habits and dietary routine.

Frequently Asked Questions

Yes, drinking hot and cold water together or in rapid succession can cause thermal shock to your tooth enamel. This can lead to tiny cracks over time and increase tooth sensitivity due to the different expansion and contraction rates of the enamel and underlying dentin.

According to Ayurveda, mixing hot and cold water can confuse your digestive system and weaken your 'agni' or digestive fire, leading to slower, less efficient digestion and potentially causing bloating or discomfort.

'Viruddh ahar' refers to incompatible foods in Ayurveda. Mixing hot and cold water is considered one such incompatible combination because it pits two opposing properties against each other, disrupting the body's natural balance.

If you mix boiled water, which is sterilized, with unboiled water, you can reintroduce any pathogens or microorganisms present in the unboiled water. This is especially a concern in areas with questionable water quality.

While many people do this without immediate issue, the thermal shock to your teeth is a concern. The rapid change in temperature can stress your tooth enamel. It can also cause a shock to your system, though the impact on digestion is not as significant as when drinking water.

Ayurveda generally recommends drinking water at room temperature or slightly warm, especially with meals. This is considered easier for the body to digest and helps maintain a balanced internal temperature.

While the effects are largely based on traditional medicine, modern studies have shown that extreme temperatures can affect gastric motility and the rate of gastric emptying. Thermal shock to teeth is also a valid concern supported by dental knowledge.