Bernadette Keefe MD
In U.S. collegiate sports, “The Elite Eight“, are the final eight teams in the national tournament; two from each region. The outcome of those four games becomes, “The Final Four”. However, for this summer time edition of The Elite Eight, we’re talking about the revered “eight glasses of plain water per day” health dictum.
While optimal hydration is essential for health, and water is considered the “gold standard” of hydration, we do not need 64 ounces of plain water a day. We do, however, need 64 ounces or 1.9 liters of total fluid obtained via drinks and food for optimal functioning and health, especially during the warm weather and exercise.
Furthermore, what makes the eight glasses of water per day advice “elite”/special is that consuming a zero calorie beverage might just be the antidote to the current epidemic of obesity and Type 2 diabetes. Americans typically satisfy their thirst with sugary beverages. Shockingly, these drinks contribute the majority of our daily ingestion of sugar!
For many, thirst and hunger signals can be easily confused, that is, we feel the need to eat when we are just thirsty. Given this confusion, when we feel hunger pangs, it’s best to remember “the elite eight” and drink water first!
In this piece, I wish to cover the basics of dehydration and hydration and the body’s fluid regulation including the thirst mechanism, the high-risk populations for dehydration, the drinks – obesity connection, and the most effective, healthy and fun ways of staying hydrated. Ultimately, we need “the elite eight” through food and drinks, but we can, and, must make the hydration healthy. Furthermore, to insure our success and foster enjoyment, we can strive to be creative about it!
The Nutritional Role of Water
The human body is 70-75 % water. Sixty percent of that water is located within our cells, some cells having minimal water (bone cells are 10% water), others a lot more (muscle cells are 70% water). In general, fat and fat cells contain less water. The remaining 40% of body water is outside of the cells, within fluids such as blood and in the digestive and urinary tracts.
Water participates in a number of essential bodily functions:
- As a primary building block of cells
- As an insulator, regulating internal body temperature.
- In the digestion of proteins and carbohydrates used as food.
- For lubrication of joints, and keeping body surfaces such as the eye moist.
- For insulation and as a shock absorber around organs and the fetus.
- Used to flush waste and toxins from the body and urine.
The human body is mostly water, and look how much water does for us!
Maintaining The Body’s Fluid Balance
Our bodies need to be in fluid balance, that is, our input needs to match our output. This type of regulation is not unlike that of our caloric needs and weight. To maintain body weight, and neither lose or gain, we must ingest the same number of calories we expend. Likewise to maintain that perfect balance of hydration that our cells, and our organs need, daily fluid input must make up for daily fluid output.
The following image shows the sources of average daily inflows and outflows of body water.
Although there have been reports stating that the population is chronically dehydrated, there is no evidence to support this. While certain populations are at risk for dehydration, in the population at large, dehydration is not a problem. This is due to a dual system of signaling to maintain balance, one for water output and the other for water input/ingestion.
Keep this chart handy to check whether you are adequately hydrated!
The Regulation of Water Output – ADH
Water output is regulated by a hormone called vasopressin, or ADH (anti-diuretic hormone). This hormone is released when the percentage of water in the blood declines. The resulting effect is that less water is removed from circulating blood by the kidneys thus causing us to urinate less. This process is described in the slide below:
The Regulation of Water Input – The “Thirst Center”
The body’s thirst center, located in the hypothalamus, is activated when we have lost about 2-3% of our body’s water. Thirst is also stimulated by a decrease blood pressure, or increased ingestion of salt.
Given that the thirst mechanism is robust in most people, is there really a reason to continue to think about daily fluid intake, 64 ounces and “the elite eight”? Probably so, when one considers that the thirst response is only activated after we are dehydrated. Avoiding this need for “catch-up” is a good reason to think of water intake as “the elite eight”.
Another reason for “keeping ahead of the game” is that we can easily mistake the sensation of thirst for being hungry, therefore reaching for something to eat and not a drink! It is only after eating, and still feeling thirsty, that we drink. The added caloric intake of food was not necessary. Compounded with a poor drink choice, we are ultimately saddled with weight gain.
The following summary slide on sensations of thirst and hunger is useful.
Dehydration – Risk Factors and Warning Signs
There are known risk factors for, and populations at risk of, dehydration. In these situations, it is prudent to be particularly proactive/attentive about hydration.
The Risk Factors – 4 As
- Acute disease – with fever/infection, gastrointestinal upset and other illnesses the body loses water through evaporation, increasing water loss and decreasing water intake
- Alcohol –Alcohol-containing beverages can adversely impact fluid balance by blocking the release of ADH, thus increasing fluid loss through urination. If not counter-balanced by drinking water, dehydration will ensue.
- Aging – The older person may have a diminished thirst sensation causing a decrease in their desire to drink and a decrease in their overall intake of fluids. Note that people are at risk both at home and in-hospital.
- Also: In Exercise and Hot weather – increase evaporation from skin and perspiration, resulting in overall water depletion. In these conditions, it’s not recommended to wait until you are thirsty to take a drink!
My go-to sports and exercise orthopedist, Dr. Howard J. Luks gives the following advice about hydration during and after intense exercise. Here he describes the ways that certain sports drinks are preferable to simple water when doing vigorous exercise.
Certain sports drinks, which contain essential minerals which you also lose during exercise are considered better for rehydration and recovery purposes. This paper showed that your recovery is enhanced with sports drinks containing sugars and protein which help replenish muscle glycogen stores and aids in muscle recovery. Hydration powders contain minerals and some contain glucose. By containing minerals, the fluid more closely matches the osmolality of your blood and therefore reduces the chance of over-hydration and creating a condition called hyponatremia — where your sodium levels drop too low. –See References
The Warning Signs of Dehydration
Most of us are familiar with the symptoms of mild dehydration. The info-graphic below provides a reminder of the degrees of dehydration and accompanying symptoms. Given upcoming long hours spent outside during warm summer weather for many school age children, the possibility of inadequate/absent air conditioning for cooling with summer storms, and our aging population, this information is worth knowing!
How to Hydrate Healthfully
A ) Drinks- Water, & Water Infusions
The other side of the hydration/dehydration coin is the tragedy of obesity and diabetes which is fueled, in no small measure, by our drinks choices. Despite the readily available zero calorie choice of water, many people choose beverages which are heavily sugared and highly caloric, such as: juices, sodas, and smoothies and sweetened coffees. Many of the latter could easily double as desert shakes. Replacement of these high calorie drinks with plain water or water infusions would be a significant step in curbing, even reversing, the obesity epidemic.
The infographic below shows how easily we can consume 50-75% of the recommended calorie intake in drinks alone. Notably most of these drinks provide minimal nutritional content.
There is, however, a refreshing, low calorie and appealing alternative to those sugary drinks: water infusions. Water infusions are cold drinks made with chilled water, ice and cut up juicy fruits or vegetables. In the winter, hot teas provide another type of healthy infused water! Replacement of high calorie drinks with water infusions would greatly decrease our total daily caloric and sugar intake.
B.) Foods – Juicy fruits and vegetables
Happily, we are not confined to drinks when trying to maintain normal hydration. A wide variety of foods, especially the succulent fruits and vegetables of summer, contain abundant water and can provide much of our hydration needs.
Below are several info-graphics on the top hydrating fruits and vegetables. They might be useful additions to your home/office refrigerator!
In summary, the health maxim “eight glasses or 64 ounces of water per day” is not “The Elite Eight”. The special/ “elite” eight is the 64 ounces of fluid we want to ingest daily by eating healthy, juicy fruits and vegetables and drinking refreshing, low calorie water infusions. Small amounts of coffee, abundant hot and cold tea infusions, and, of course, added plain water are all great!
Additionally, since we are already 2-3% dehydrated when the thirst mechanism kicks in and we may confuse thirst with hunger, a smart course of action is to be proactive in our hydration habits and think “The Elite Eight First”. This is especially important in the summer, during outdoor sports and routine exercise, and in the aging population who have diminished thirst sensation.
So let’s have a renewed interest in the “The Elite Eight” and craft healthier ways to keep up with our fluids!
“The Elite Eight” Recipe:
- Start with simple water
- Add ice and juicy fruits to make a drink infusion
- For eating: enjoy fresh, juicy, fruits and vegetables in abundance!
The above is a rule of thumb for food!
Meanwhile, avoid the other drink choices as much as possible!
Finally: It’s summer! Quench your thirst with infused waters, and juicy fruits, revel at the beach and in the waves, and, “get sleep” with this relaxing video!
1.) Water alternatives- Infused waters
Fresh Ideas For Making Infused Water
Keep it simple. Think of flavor combos you like in other recipes and build from there. Here are some ideas to get you started:
- Cucumber + lime + strawberry + mint
- Lemon + raspberry + rosemary
- Orange + blueberry + basil
- Lime + ginger root + basil
- Watermelon + honeydew + mint
- Cucumber + mint + jalapeno
- Lemon + thyme
- Orange + hibiscus + star anise
- Orange + cinnamon + cardamom + cloves
- Pear + fennel
2.) The Stone Belt – geographic area in the United States, largely south and southeast, which has an increased incidence of kidney stones, due to higher risk of dehydration.
Kidney Stone Belt http://ncpedia.org/kidney-stone-belt
3). Info-Graphic Home Treatment of Dehydration
4.) Drinking Water Facts
19 Countries With The Cleanest Tap Water To Drink
5) Water: A precious resource
Yet Another ‘Footprint’ to Worry About: Water
Quote from above:
It takes roughly 20 gallons of water to make a pint of beer, as much as 132 gallons of water to make a 2-liter bottle of soda, and about 500 gallons, including water used to grow, dye and process the cotton, to make a pair of Levi’s stonewashed jeans.
How Much Water Actually Goes Into Making A Bottle Of Water?
How Much Water Does It Take to Make One Steak?
No, You Do Not Have to Drink 8 Glasses of Water a Day
Do we really need eight glasses of water a day?
Water: How much should you drink every day?
Daily Water Intake Among U.S. Men and Women, 2009–2012
Physiology of Hydration
Water balance, fluids and the importance of good hydration
How Much of Your Body Is Water?
12 Unexpected Reasons to Drink More Water
The Regulation of Fluid Balance in the Body
Water Balance: ADH, Angiotensin, Aldosterone
Recognising and preventing dehydration among patients
Dehydration and Heat Stroke
The Thirst Mechanism – Thirst/Hunger Connection
The Neural Regulation of Thirst
From: Central Nervous System Dr. Anderson GCIT. Animal Body Plans.
Are you hungry or thirsty? It’s hard to tell
Healthy Hydration Through the Diet
8 Amazing Infused Water Recipes To Drink Instead of Soda
Water vs. Soda
IWK Health Centre stops selling pop and juice
Fresh Ideas For Making Infused Water
Exercise and Hydration
5 Ways To Enhance Your Exercise Recovery