It’s commonly understood that drinking eight glasses of water per day is fundamental to everyday health and wellness. Of course, humans need water to survive, but this number has been ingrained in our minds as the optimal amount for many years. But where does this advice come from, and how accurate is it? Are eight glasses enough to stay hydrated for everyone?
Importance of Drinking Water Daily
Our bodies are made up of about 60-70% water, some of which gets lost through breathing, sweating, urine, and daily bowel movements. Water is an essential nutrient, and replenishing fluids is important to staying healthy.
In fact, drinking enough water:
- Helps you remove waste from your body through your urine, stool, and sweat
- Prevents your body from overheating
- Keeps your joints cushioned and lubricated
- Adds to skin health and keeps your skin plump
- Decreases the risk of kidney stones
Lack of water can lead to dehydration. Even mild dehydration can cause fatigue, confusion or short-term memory loss, and mood changes like increased irritability or depression. Dehydration can also increase the risk of certain medical conditions such as urinary tract infections, gallstones, and constipation.
Is Eight Glasses the Magic Number?
The short answer is no. The long answer is a bit more complicated.
In 1945, the U.S. Food and Nutrition Board of the National Research Council made an official recommendation for daily water intake of eight glasses per day, or roughly 64 ounces total. While it’s hard to pinpoint the exact reasoning behind this rule, it’s theorized that it might be based on 1 ml of water per calorie of food consumed. With the average diet consisting of 2,000 calories per day, this adds up to 2,000ml or eight 8-ounce glasses.
Perhaps surprisingly, this recommendation was not meant to encourage people to drink eight 8 oz glasses of plain water every day but instead represent the total water intake from all food and beverage sources combined.
Research now shows that to be properly hydrated, people need about nine to 13 cups of water a day. This includes getting fluids from water, other beverages, and foods. Additionally, this number should be used as a general guide since a person’s needs can vary significantly based on several different factors.
This includes:
- Weight: As body weight increases, fluid needs increase as well.
- Diet: 20% of our water intake comes from fluid-rich foods such as lettuce, leafy greens, cucumbers, bell peppers, summer squash, celery, berries, and melons, so eating ample amounts of these foods will reduce the amount of water you need to actively drink.
- Activity level: Increased sweating from exercising means you’ll need to drink more water to replace the fluids you’re losing. Unfortunately, it’s difficult to calculate fluid loss from sweat.
- Pregnancy: Pregnant women require additional fluids to maintain amniotic fluid levels to keep their babies healthy. Similarly, nursing mothers need more water so their bodies can produce enough milk.
- Sickness: Symptoms of illnesses, such as fever or vomiting, will cause excessive loss of body fluids that need to be replenished.
- Environment: People living in hot, humid, or dry areas will need more water than those in other climates.
- Medications: People on certain medications, such as those to treat high blood pressure, might need to drink more water to combat fluid loss and dehydration.
The most important thing is to listen to your body. Simply put, drink water if you are thirsty and stop when you’re not thirsty anymore. Our bodies are designed to send thirst signals to our brain when we need fluids, giving us the desire to drink.
It’s significant to note, however, that the body’s regulation of fluid intake and thirst can start to decline as we age. If you find yourself not feeling thirsty throughout the day even though you’re not drinking water, it’s essential to find other strategies to avoid dehydration. A common strategy is to buy a daily intake water bottle with markers for drinking a certain amount of water by a certain time. You can also set alarms or reminders on your cell phone or use a water intake app that can help you track how much you’re drinking throughout the day.
If plain water starts to bore you, try adding slices of your favorite fruits such as lemons or vegetables like cucumbers for extra flavor. Unsweetened seltzer water is also a great option to give you some variety without increasing your sugar intake.
If you struggle to stay properly hydrated, your Atrius Health provider is here to help you make healthy, sustainable choices that make sense for you and your goals.
