There is no question that adequate hydration is extremely important, as water is a critical nutrient, and in fact, the one nutrient we can survive the least amount of time without. However, as important as water is –not just to our health, but survival as well- it may surprise you to know that there have never been any scientific studies done to support any universal requirements.
Despite the lack of evidence through scientific studies, we do know that due to the loss of water through breathing, sweating, urination and digestion, the average adult needs to replace approximately 2 liters of lost fluid each day. This is where I suspect the 8 x 8 mantra was originally established. We’ve all heard the 8 x 8 rule –drink eight – 8 ounce glasses of water each day.
Although this oversimplification seems to be a fairly respectable amount for the average adult, other factors, such as; body size, activity level and health status also play a role. Because of this, I have established some fairly significant guidelines (that I use with my clients), which I will outline toward the end of this article.
Today, too many of us rely on coffee, fruit drinks, soft drinks, and other such products as a means of satisfying our thirst. What many of us don’t realize is that nearly all of these drinks, in fact, don’t hydrate, but actually dehydrate the body. Good hydration, simply put, is as important as good eating.
In fact, despite the lack of scientific studies, our bodies require a minimum amount of clean, pure water every day to maintain a properly balanced level of hydration. Proper hydration increases cell communication, resulting in better health. Water transports chemical messengers, hormones and nutrients to vital organs, which in turn produce substances that are made available to the rest of the body for proper and efficient functioning.
On average, the human body consists of approximately 70 percent water and provides hydration to every single living cell. Water is the medium for all of our body’s metabolic changes, and is necessary for nutrient transportation, blood flow, oxygen delivery, lubrication, waste elimination and body temperature regulation. (1)
Let’s look at some important reasons why proper hydration is so important.
Water Helps Aid Weight Loss
Optimizing your water consumption can help you lose weight due to the fact that water actually has a satiating effect while increasing protein synthesis and metabolic rate. In several studies, drinking 500ml or approximately two 8oz glasses of water was shown to increase ones metabolism by as much as 30 percent for up to one hour. (2)
So, what this tells us is that drinking your recommended eight – 8oz glasses of water everyday can increase your total energy expenditure by nearly 100 calories per day.
Timing your water intake may play a factor as well. Drinking water thirty minutes prior to meals has an impact on overall food consumption. It has a satiating effect making you feel full faster, preventing the over-consumption of unnecessary calories. (3, 4)
In one study, dieting individuals who drank just 500ml or 16.9oz of water before meals lost 44 percent more weight, over a twelve week period compared to the non-water drinking group. (5)
Additionally, it is actually best to drink chilled water, because the body expends additional energy to heat the water up to body temperature. (6)
Proper Hydration Helps Maximize Physical Performance
Due to the fact that lean muscle tissue contains approximately 75 percent water, if we do not stay well hydrated, physical performance can suffer dramatically. This is particularly important during both intense physical activity and high heat.
Dehydration can set in after losing as little as just 2 percent of your body’s water content, and have a noticeable effect. However, it is not uncommon for athletes to lose as much as 6 to 10 percent of their total water though perspiration. This can lead to altered body temperature control, reduced motivation, and increased fatigue which makes exercise much more difficult, both physically and mentally. (7, 8, 9)
Optimal hydration has been shown to prevent this from happening, and may even reduce the oxidative stress that can occur during intense exercise. This is not surprising when you consider that muscle is about 75 percent water. So, if you exercise intensely and/or tend to sweat a lot, then staying adequately hydrated will help you perform at your absolute best. (10, 11)
The Brain/Water Connection
Our brain is strongly influenced by our water consumption and hydration status. Just mild dehydration or a loss of fluid as little as just 1 percent can impair our energy level and mood. This, in turn, can lead to major reductions in memory and brain performance. A fluid loss of just 1 to 3 percent equals approximately 1.5 to 4.5 pounds of total body weight loss for a 150 pound person. This can easily occur through normal daily activities, let alone during exercise or high heat.
Studies suggest that even mild dehydration of 1 to 3 percent of body weight can impair our brains ability to function properly and efficiently. In one particular study, young women who had a fluid loss of just 1.36 percent after exercise had impaired mood, concentration and increase perception of task difficulties. In another similar study, young men who had a fluid loss of 1.59 percent induced adverse changes in vigilance and working memory, and increased tension, anxiety and fatigue. (12, 13)
Many other studies, ranging from children to the elderly, have shown that mild dehydration can impair mood, memory and brain performance as well. (14, 15, 16, 17)
Hydration and Constipation Relief
Constipation is a common problem among the masses. Characterized as a condition in which there is difficulty in emptying the bowels or infrequent bowel movements, its most common symptoms are:
- Infrequent bowel movements
- Difficulty having bowel movements
- Hard or small stools.
- Sense of incomplete bowel movement.
- Swollen abdomen or abdominal pain.
- Vomiting.
Low water consumption appears to be a major risk factor for constipation in both young and elderly individuals. For this reason increasing your fluid intake is often recommended as a part of the treatment protocol, and there is some good evidence to back this up. (18, 19)
In several studies, carbonated water has shown particularly promising results for constipation relief, although the reasons need to be further investigated. (20, 21)
In conclusion, drinking plenty of water has shown clear promise in the prevention and relief of constipation, especially in people who generally do not drink an adequate amount.
Hydrate for Headaches and Hangovers
Insufficient fluid intake can trigger headaches and migraines and is a common symptom of dehydration in many individuals. (22, 23)
Several studies have shown that water can relieve headaches in those who are dehydrated. In fact one particular study found that although water had little to no effect on the frequency of headaches it did reduce the intensity and duration. (24, 25)
A hangover is referred to as unpleasant symptoms experienced after the over-indulgence of alcohol. Alcohol is not only a toxin but a diuretic as well, meaning it makes you lose more water than you take in. This consequently leads to dehydration. (26, 27)
Evidence tells us that hangovers are, at least partly, caused by dehydration so drinking water can help reduce some of the main symptoms of hangovers. A good way to reduce the effects of a hangover is to drink a glass of water between each drink, and to have at least one big glass of water before going to bed.
Dehydration Red Flag
Although our bodies have been designed with built in control mechanisms to help us sense our hydration status, these mechanisms may be slow at letting us know exactly where we are on the hydration scale. Two common indicators are:
- Thirst
- Urine color
While thirst may be a good indicator that a drink would help maintain good hydration, it may actually imply that you are already in a dehydrated state. Outside of being thirsty, the color of your urine can give you clues on the current status of your hydration level. If your urine is bright yellow, you are already approaching a dehydrated state. The darker your urine, the more dehydrated you are. These are both clear indicators that you are behind the curve on staying well hydrated.
How Much Water Is Best For YOU?
As we can see, staying optimally hydrated is crucial for many reasons. And although the 8 x 8 rule has been handed down for generations there is more concrete evidence – even though it’s not backed by any scientific studies- pointing to a more favorable hydration level according to body weight, health status and performance level.
So, for those of you who’d like to take your hydration to a level more specific to your bodies needs under your current situation use my outlined method below.
Calculating your water intake specific to your current situation:
Weight loss – If you are looking to lose weight, have metabolic abnormalities, and/or both then take in a minimum of 0.5oz of pure fresh water -per desired goal weight- each day.
Example:
Goal weight 150 pounds
(150 x 0.5oz = 75oz)
Weight Maintenance – If you are looking to maintain your current weight then shoot for 0.35 to 0.4oz of pure fresh water each day. This range works perfect for children as well.
Example:
Current weight 150 pounds
(Range: 52.5oz to 60oz)
Athlete – If you are an athlete looking to maximize your performance then shooting for 0.65oz to 0.75oz of pure fresh water each day –per pound of lean body mass- would be ideal.
Example:
Current weight: 220 pounds
Current Body-fat: 10 percent
220 – 10 percent = 198 pounds/lean mass
(198 x 0.75oz = 148.5oz)
Some interesting facts to note:
- The human brain is composed of 70 percent water.
- The lungs are composed of nearly 90 percent water.
- Lean muscle tissue contains about 75 percent water.
- Our bones are composed of 22 percent water.
- Body-fat contains 10 percent water.
- Our blood is made up of nearly 80 percent water.
- Each day we must replace approximately 2 liters of water lost through breathing, perspiration and digestion.
