Drink 8 Glasses of Water a Day: Fact or Fiction?
If there is one health myth that will not die, it is this “You should drink eight glasses of water a day”.
It’s just not true. There is no science behind it.
The source of the 8x8 rule has not been confirmed.
One theory suggests it may have originated in 1945, when one research organization released a report stating that the average person needs to consume 1 ml of water per calorie of food they consume.
Another plausible origin of the 8x8 rule is the work of a nutritionist named Dr. Frederick Stare. He co authored a book published in 1974 that recommended drinking six to eight glasses of water per day.
It's unknown where the recommendation to drink eight 8-oz glasses of water per day comes from originally, but a couple of theories exist.
While there are certainly circumstances in which water needs increase, healthy men and women generally don't need to be consuming water in such large quantities.
On the other hand, not drinking enough water can cause mild dehydration, defined as the loss of 1–2% of body weight due to fluid loss. In this state, you may experience fatigue, headache and impaired mood.
But in order to stay hydrated and avoid mild dehydration, you don't need to rigorously follow the 8x8 rule. Luckily, you have a built-in instinct called thirst.
For this reason, most people don't need to worry about their water intake — thirst will tell you when you need water.
Besides water, other foods and beverages you ingest also contribute to your overall daily intake of fluids and help keep you hydrated. Some water is also created within your body through metabolism.
Drinking eight glasses of water per day may be more than enough for some people, but it may be too little for others.
If you want to keep things simple, just listen to your body and let thirst be your guide.
Taking all this into account, it's clear that water needs are highly individual.
However, drinking enough water has its health benefits:
- Weight loss: Drinking enough water may help you burn more calories, reducing appetite if consumed before a meal and lowering the risk of long-term weight gain.
- Better physical performance: Modest dehydration may impair physical performance. Losing only 2% of your body's water content during exercise may increase fatigue and reduce motivation.
- Reduced severity of headaches: For those prone to headaches, drinking additional water may reduce the intensity and duration of episodes. In dehydrated individuals, water may help relieve headache symptoms.
- Constipation relief and prevention: In people who are dehydrated, drinking enough water may help prevent and relieve constipation.
- Decreased risk of kidney stones: Although more research is needed, there is some evidence that increasing water consumption may help prevent recurrence in people with a tendency to form kidney stones.