How to Drink Water Wisely

Too little water dehydrates you, but too much can be dangerous.

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A secondary school student in Taiwan participated in a water-drinking competition and guzzled 6,000 milliliters of water in just 30 minutes. Upon returning home, he suffered dizziness, vomiting, and convulsions and was rushed to the hospital, where he nearly lost his life. This is a classic case of “acute water intoxication”—also called water poisoning—which happens when drinking too much water dilutes sodium levels in the blood, disrupting brain and body function.

Although water is the source of life, more or less is not always better.

TCM Perspective on Water Metabolism

Many people eagerly guzzle water in the summer, without realizing that their kidneys—which play a central role in water metabolism—have limits and might not be able to cope. Water retention can lead to swollen hands and feet, frequent urination, and insomnia, which can impair sleep quality and worsen energy levels.

However, from a TCM perspective, water metabolism relies not only on kidney function but also on a strong spleen. The spleen is part of the same energy system as the stomach, intestines, and pancreas. It is also responsible for nutrient absorption and water metabolism.

A weak spleen and stomach function can cause “dampness,” or excess moisture and water retention in the body when drinking too much. This type of person exhibits several characteristics: facial swelling, cold hands and feet, and a dry mouth despite drinking water all day. Such people worsen their imbalance by drinking water excessively, creating a cycle of bloating and sluggish energy.

How Much Water Should You Drink in a Day?

There is no single standard answer to this question. The amount of water you drink should be adjusted based on your constitution, weather conditions, and lifestyle habits. Rather than blindly pursuing a fixed number, it is more important to listen to your body’s needs.

The human body has a built-in “water alarm”—osmoreceptors—that constantly monitor blood concentration. When blood concentration is too high, the brain naturally sends a thirst signal, and drinking water provides the hydration your body really needs.

In addition, your daily lifestyle can also affect your water intake. Do you spend all day in an air-conditioned room? Do you exercise a lot? Do you sweat profusely? These factors directly affect how much water you need.

The easiest way to determine if you are dehydrated is to observe the color of your urine.

• Clear and colorless urine indicates excessive drinking.
• Light yellow is ideal, indicating adequate hydration and normal metabolism.
• Dark yellow to orange indicates dehydration and requires immediate rehydration.
• Dark-orange or brown urine may indicate liver or other metabolic issues. Drinking water alone may not be enough, and you should seek medical attention immediately.

It is worth noting that urine color can also be affected by diet. For example, eating dragon fruit, beetroot, or taking B vitamins can cause urine to appear reddish or yellowish. Therefore, determining dehydration requires a comprehensive assessment, and you should try not to panic over a single color change. A yellowish first urine in the morning is normal and usually just the result of a night without hydration. With adequate hydration, the color will gradually fade.

Conditional Factors Affecting Water Intake

Different constitutions require different amounts of water. If you have a hot constitution and are prone to sweating and dry mouth, your water needs will be higher. Conversely, if you have a cold constitution, are prone to cold hands and feet, or experience frequent diarrhea, drinking excessive water is not recommended. Too much water can damage the spleen and kidneys.

Some people believe drinking plenty of water helps with bowel movements. However, TCM expert Kuo-Pin Wu said that while this practice may be effective for most people, drinking water on an empty stomach may be counterproductive for constipated people with weak constitutions.

He described one of his patients who sought relief from constipation by drinking a large glass of water (approximately 300 to 500 milliliters) every morning on an empty stomach. His constipation did not improve, and he developed eczema and flatulence. In TCM, eczema is considered a sign of excess dampness. Wu advised the patient to avoid drinking too much water before breakfast, and to drink only about 100 milliliters if thirsty. After a week, the patient’s constipation improved.

Why the 1st Glass of Water Matters

The first glass of water each day is life-saving. After a full night’s sleep, the body is mildly dehydrated. This means the blood has less fluid, making it more concentrated (higher viscosity). At the same time, blood pressure naturally rises in the early morning hours, and the risk of heart attack or stroke is statistically highest right after waking. For those with cardiovascular problems, this combination—thicker blood plus higher blood pressure—can strain the heart and blood vessels.

Drinking a glass of warm water first thing in the morning helps thin the blood, improve circulation, and reduce the morning surge in cardiovascular risk. In short, it lowers the chance of blood clots forming and eases pressure on the heart.

Even for people without heart disease, this morning glass of water provides key health benefits:

• Rehydration: Replaces fluid lost through breathing and sweating overnight.
• Digestive Support: Stimulates the stomach and intestines to start the day’s metabolism. For most people, this can help with bowel movements, but those with constipation and weak constitutions should drink only in moderation.
• Detoxification: Encourages kidney function and helps flush metabolic waste.
• Energy Boost: Restores hydration balance, making the body feel lighter and more energized.

After waking up in the morning, drink a 200-milliliter glass of warm water. Drink it in small sips, allowing the water to be absorbed gradually. Never gulp it down in one go, as drinking excessive amounts of water quickly can suddenly dilute the blood, increasing the strain on the heart and kidneys.

Other Key Times to Rehydrate

Besides the importance of morning hydration, there are other situations when drinking water is particularly important:

1. Afternoon Fatigue: Many office workers start yawning in the afternoon, not because they are truly tired, but because they are slightly dehydrated. When you feel sluggish around 2 or 3 p.m., drink a glass of water to refresh yourself and improve concentration.
2. Excessive Sweating: Exercise, hot springs, and baths cause rapid water loss. Failure to replenish water can lead to poor temperature regulation and even heatstroke.
3. Air Travel: On planes, cabin humidity is around 20 percent. The dry air can dehydrate the skin, so frequent hydration is essential.

Dehydration doesn’t just affect the body—it also can lead to slower mental agility and depressed mood. Studies have found that losing 2 percent of body weight in water impairs cognitive abilities, particularly in attention, executive function, and motor coordination. Therefore, hydration in the right quantity is important.