There’s no doubt that water comes with its whole host of benefits. I mean, approximately 60% of the human body (and 90% of our blood) is made up of water, so it must be important (4).
On top of that, we’re told to drink at least eight 8-ounce glasses of water per day—which has been dubbed the “8x8 rule” (5). However, this rule has been widely criticized due to the fact that it’s limited to healthy adults in a temperate climate who live a pretty sedentary lifestyle.
What the Institute of Medicine now recommends is that the average woman should drink approximately 74 ounces (about 9 cups) of water per day, and the average man drink 101 ounces (about 13 cups) per day (6).
The table below is what Americans were drinking before and after the start of the 8x8 rule. The “before” dates back to a survey by Ershow and Cantor in 1977-78.
Native Note: Caffeine (and alcoholic beverages like beer, but to a lesser extent) may be counted toward the daily total, where they used to not count toward one’s daily fluid intake.
1. Water Can Optimize Physical Performance
The normal turnover of water is approximately 4% of the total body weight in adults. So if you’re a 70 kg adult, this is equivalent to turning over 2,500-3,000 ml (or 84-101 fluid ounces) of water per day (7). And that’s excluding perspiration.
Based on the evidence derived from nine different articles, dehydration has a negative impact on physical performance for any activity lasting longer than 30 seconds (8, 9).
Even modest dehydration of a 2% reduction in body mass impairs normal bodily functions and performance (10).
In comes collagen, which demonstrated a significant increase in fat-free mass in a 2019 study conducted on 57 fit young men (11). This study took place over 12 weeks and included resistance training three times a week along with 15 grams of collagen peptides per day.
2. Water Enhances Energy & Brain Function
Did you know that those who drink their water increase their reaction time by 14% (12)?
Well, that’s what Dr. Caroline Edmonds and her team found. Not only did dehydration decrease cognitive performance, it also led to people being more confused and tense.
To make sure that you’re keeping your brain healthy and hydrated, follow these guidelines by the Institute of Medicine:
- Females: 74 ounces of water per day (approximately 9 cups)
- Males: 101 ounces of water per day (approximately 13 cups)
3. Water Reduces Caloric Intake
In a 2016 study, 18,300 U.S. adults were surveyed on their dietary habits (13).
The findings: Those who increased their consumption of water by just 1% reduced their daily calorie intake as well as their consumption of saturated fat, sugar, sodium, and cholesterol.
Yes, you heard that right—for those who simply added 1 to 3 cups of water each day, their calorie intake decreased by 68 to 205 calories.
4. Good Hydration Leads to Healthier, Supple Skin
As beauty aisles become more and more crowded with their billion-and-one anti-aging serums promising you radiant, younger-looking skin, water fades into the background.
That is until a study conducted in 2007 by the International Journal of Cosmetic Science. This study showed that drinking 9.5 cups of water every day for four weeks altered skin density and thickness (14).
And if that not enough, a study by the University of Missouri, Columbia showed that drinking about 2 cups of water increased blood flow to the skin.
5. Lubricates the Joints
Did you know that cartilage—found in your joints and the disks of your spine—contains 80% water (15)?
Remaining hydrated can keep your cartilage feeling lumber and ache-free, whereas dehydration can bring on joint pain due to the reduction of your joints’ shock-absorbing ability.
