Daily fluid intake
We often hear people say "drinking more water is healthier, " but did you know that drinking too much water can actually harm your body—and in severe cases, even be life-threatening? Today, let’s dive into the topic of "drinking water"—something that seems simple, but actually holds a lot of important knowledge.
1. What Happens to Your Body When You Drink Too Much Water?
When you consume an excessive amount of water, your kidneys can’t expel it in time. This leads to the over-dilution of sodium in your blood, a condition medically known as "water intoxication" or "hyponatremia."
Once hyponatremia occurs, the osmotic pressure of the blood decreases, and water seeps into cells—even brain cells aren’t spared. Cell swelling triggers a range of discomforts, with common symptoms including:
- Headaches and dizziness, feeling as groggy as if hit by a heavy object
- Nausea and vomiting, with no appetite for food
- Severe fatigue, even feeling too weak to walk
- Confusion, unable to focus at all
- Muscle cramps and weakness, which may even affect normal movement
While life-threatening severe cases are relatively rare, they do happen:
- In 2007, a radio show contestant drank nearly 2 gallons (about 7.5 liters) of water in 2 hours to win a prize, ultimately dying from water intoxication.
- Not long ago, actress Brooke Shields also revealed publicly that she once suffered a generalized tonic-clonic seizure (a major seizure) due to excessive water intake, narrowly escaping a serious accident.
2. How Much Water Is "Enough"? Stop Falling for the "8-Glass Myth"!
Many people firmly believe that "drinking 8 glasses of 8-ounce (about 200ml) water a day is healthy, " but this is actually a long-standing myth—there is currently no scientific research to support this claim.
In reality, there is no universal standard for "how much water to drink. " It varies from person to person and is mainly influenced by 3 factors:
- Personal health conditions: For example, whether you have underlying diseases like kidney disease or diabetes
- Daily activity level: People who exercise more and sweat heavily naturally need more water
- Dietary structure: Eating water-rich foods (such as watermelons, cucumbers, soups, and porridges) can also supplement a portion of your daily fluid needs
According to recommendations from the U.S. National Academy of Medicine:
- Healthy adult men need approximately 15 cups (about 3.5 liters) of fluid per day
- Healthy adult women need approximately 11 cups (about 2.5 liters) per day
A crucial reminder here: this amount includes all fluids obtained from both food and drinks. Around 20% of your daily fluid intake comes from your diet—such as fruits, vegetables, and staple foods you eat. So, the amount of "plain water" you actually need to drink is not as much as you might think.
Here are 2 simple ways to judge your hydration needs and master your drinking rhythm easily:
- Follow your thirst: For healthy people, drinking water when you feel thirsty is sufficient—there’s no need to force yourself to "chug" water.
- Check your urine color: This is the most straightforward method! Light yellow urine means you’re well-hydrated; if it’s dark yellow, it’s a sign that you need to drink more water.
Additionally, you may need to drink more water than usual in these special situations:
- When you have vomiting or diarrhea: Your body loses a lot of fluid, so you need to replenish water promptly to prevent dehydration.
- After intense exercise or in hot weather: You sweat heavily, so you should also increase your water intake appropriately.
3. How Much Water Is "Too Much"? These 3 Groups Need to Be Extra Careful!
Just like there’s no fixed standard for "adequate water intake, " there’s no set amount that defines "excessive water intake. " However, there’s a key reference: a healthy person’s kidneys can process approximately 1 liter of fluid per hour. If your water intake consistently exceeds this amount over several hours, you may be at risk of water intoxication.
In particular, these 3 groups are more likely to have problems due to "excessive water intake" and must be extra cautious:
- Endurance athletes: Such as marathon runners and triathletes. After long periods of high-intensity exercise, blindly drinking large amounts of water can easily lead to hyponatremia.
- People with underlying diseases: Those with kidney disease or liver disease, for example. Their kidneys and liver have reduced ability to metabolize water, so excessive intake will increase the burden on these organs.
- People taking certain medications: Drugs like diuretics, antipsychotics, and the illegal drug "ecstasy" (MDMA) may stimulate the thirst center, making people unconsciously drink too much water.
Finally, I want to say: We drink water to keep our bodies healthy, not to add burden to them. Instead of obsessing over "how much you must drink," learn to "listen to your body’s signals" and adjust based on your actual situation. Only then can you drink your way to health and comfort!