How Much Water Should We Drink?

water fountainsandragraph of fluidsshark jaws 

 

Hi everyone! My name is Sandy Rhoads and I have had the honor to mentor under Nadine Pazder during my advanced rotation as a dietetic intern through Keiser University in Lakeland, Florida. I will be graduating in August, 2014 and my realm of interest is in clinical dietetics, specifically diabetes education and research on any subject about nutrition. As you can imagine, I was thrilled when Nadine asked me to write a blog about one of the most important nutrients known to mankind, water!   I sincerely hope you enjoy my blog.

 

Confused about how much water to drink?

The reason you’re confused just might lie in the signs and symptoms associated with drinking too little or too much water. If we drink too little water it could lead to weakness, poor endurance, headache, speech difficulty, constipation, palpitations, dizziness, disorientation, and confusion. If we drink too much water it could lead to confusion, disorientation, fatigue, muscle weakness, spasms and cramps, nausea and vomiting, headache, unconsciousness, convulsions and coma. Yep, you’re confused if you drink too much and confused if you drink too little! So you may want to go get a glass of water right now, especially if you’re feeling thirsty, which would mean you have already lost 2% of your water volume and this could quite possibly lead to more confusion.

 

Why is water such an important nutrient?

Before we jump into deciphering our water needs, let’s look at why we need it. First of all, we can only survive a few days without it, whereas we can survive for weeks without food. Second, water acts as a solvent, reactant, protector, and regulator of temperature and pH in our body. When we are born, water accounts for approximately 75% of our weight. As we age this percentage declines and by the time we are adults the approximate percentage for the average male is 60% and female is 50%. This further declines in the elderly to less than 50% because the proportion of lean body mass to body fat influences the amount of water as a percentage of body weight. Generally, water accounts for 75% of muscle tissue and 10% of fat tissue. Therefore, an obese individual will also have a slight decline.water fountain

So how much water should you drink?

To answer this question we need to take a look at some of the variables that should be considered if viewing the dietary reference intakes. Although recommended water intakes vary for each continent, they typically are based on total water intake from both beverages and foods. Some of the issues we will need to consider to help us get an accurate tally of our needs are physical activity, environmental factors, and diet. These will all be discussed shortly, but first let’s review some of the ways that our body obtains the water it needs. Our bodies get the required fluid amounts through a combination of drinking water, water in beverages, and water in foods. About 70% to 80% should come from beverages and the other 20% to 30% will come from foods. Beverages range between 84% and 100% water, with fruit juices being at the lower end of the range and water being 100%. Solid foods range from 0% to 96%, with oils being 0% and cucumbers 96%.graph of fluids

 

Don’t pull your calculator out just yet!

It just so happens that a group of really smart individuals already did the work for you. These scientist and statisticians did the math by subtracting the 20% from foods and devised that the recommended amount for men is 13 cups and 9 cups for women. Below is the general guideline which includes the amounts you need to get from the water that you drink and from other beverages, even those containing caffeine.

 

The overall generallyguideline to adapt is: Adults – 19 years and older Children – Based on weight
Males: 13 cups 7 lbs. = 2 cups
Females: 9 cups 21 lbs. = 5 cups
Minimum 6 cups 44 lbs. = 8 cups

 

So what about adjusting needs for physical activity, climate and diet?

The general rule of thumb for exercise is for every one pound loss when exercising; replace with 2 cups of water. Keep in mind that prior to the exercise session you need to be well hydrated and continue to replace fluids early and often throughout your exercise session. Good sources of fluid include water, sports drinks, juices, soups, smoothies, fruits and vegetables. The fluid needs for competitive sports depend largely on the sport and the requirements are more structured. A sports dietitian can assist you in designing a personalized hydration plan that considers thirst, urine color, and body weight changes under varying conditions of exercise.

The concerns regarding adjusting water needs related to type of diet would be primarily for someone on a high fiber diet; this type of diet would require approximately 8-10 cups a day (minimum 8 cups a day). If you’re worried about not getting enough from the foods you eat, don’t be. Almost every food contains water, so it is virtually impossible to not meet those needs.

The recommended total daily beverage intake from the Institute of Medicine is for generally healthy people living in temperate climates, but for individuals that live in an area where they are exposed to extremely hot or cold temperatures; their body will use more water to maintain its normal temperature. Under these conditions, fluid intake may need to be increased. The best way to know if you are drinking enough fluid is to meet the AI, and drink water if your mouth is dry or if you are thirsty. Remember, by the time you get thirsty you have already lost 2% of your water volume and a >2% body weight loss is considered dehydration.

What else should you know?

One last “fluid for thought”…. Thirst can often be mistaken for hunger and result in unwanted weight gain. My advice would be to drink 8 ounces of water and wait 10 minutes.shark jaws

About nadineandadamblog

Nadine and Adam are mother and son. Nadine lives in Florida where she has provided outpatient MNT in a large healthsystem for the past 20 years. In addition, she teaches nutrition to second and third year family medicine residents. She is a past-spokesperson for the Academy of Nutrition and Dietetics. Adam lives in Washington State. His career has largely been involved in recipe development and food production. He is currently developing recipes and menus for the Seattle schools to meet the new federal guidelines for school nutrition programs and he does outpatient nutrition counseling. He is also a voice in PSAs over Seattle radio representing the Washington Academy of Nutrition and Dietetics.
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2 Responses to How Much Water Should We Drink?

  1. What is AI? Loved the blog and got to the end before finding something…AI…that I don’t understand the meaning of. I can see I need to start keeping a food/liquid diary. See if my dizziness and weakness problems are caused by my intake of fluids.

    Like

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