By Lori Bednarchik & Brenna Joyce
Quenching your Thirst: The Lowdown on Water
How much water should I drink each day?—such a simple question with no easy answers. We’ve all heard that we should be drinking 8 glasses a day, but how much is a glass, really? And what if I exercise? Run a marathon? Am a couch potato? Taking antibiotics? Hiking in the mountains? Got food poisoning?
The Federal Government has not established an RDA for water and though no single formula fits everyone, knowing more about your body’s need for fluids will help you estimate how much water to drink each day.
One can calculate one’s baseline needs is via the following formula:
0.5 X body weight (in pounds) = number of ounces per day
This formula gives you a baseline only. You must adjust it for the circumstances of the day. Exercise and long-term outdoor activity will increase your daily needs. Other circumstances where you’ll need to increase fluid intake include stomach problems including vomiting or diarrhea which both drain your body of water and electrolytes. If you drink protein shakes or are on a high-fiber diet you’ll need extra water to help you digest these types of foods. Certain medications including diuretics and some antibiotics will increase your daily water intake requirements, so always check with your doctor when you begin taking a new medication to see if you will need to adjust your water intake.
The human body is composed of 55 to 75 percent water.
From an athletic and fitness perspective water keep joints lubricated, reducing the likelihood of long-term connective tissue wear-and-tear. It also allows your body to regulate temperature—cooling your body with moisture (perspiration) that evaporates from your skin. It provides a medium in which biochemical reactions such as metabolism (digesting food, producing energy, and building tissue) occur making water important for recovering from exercise. If your body is allowed to dehydrate during exercise, you are more likely to fatigue quicker, lose coordination and experience muscle cramping.
From an overall wellness perspective, water helps to regulate appetite and has an important role in the digestive process; dissolving nutrients so that they can pass through the intestinal cell walls into your bloodstream, and move food along through your intestinal tract efficiently to reduce the likelihood of constipation.
Water can also decrease illness severity, add moisture to the skin, flush wastes out of the body, and helps keep your energy level up.
Beyond the Tap: Other Sources of Water
On average, food provides about 20 percent of total water intake, while the remaining 80 percent comes from water and beverages of all kinds. Foods that melt at room temperature (think Jello and frozen yogurt) and broth based soups contain plenty of fluids. To give you an idea of water content, check out this list of high water content foods:
| Food | Serving Suggestion | Percentage H2O |
|---|---|---|
| Lettuce | 1 ½ cup | 95% |
| Watermelon | 1 ½ cup | 92% |
| Broccoli | 1 ½ cup | 91% |
| Grapefruit | 1 ½ cup | 91% |
| Milk | 1 cup | 89% |
| Orange juice | 3/4 cup | 88% |
| Carrot | 1 ½ cup | 87% |
| Yogurt | 1 cup | 85% |
| Apple | 1 medium | 84% |
Beyond the Tap: Other Sources of Water
- Start hydrating early by drinking 1-2 glasses of water in the morning.
- Keep a water bottle with you all day long. Order eco-friendly, and stylish (reusable) water bottles from www.mysigg.com.
- Drink even when you are not thirsty.
- Drink 1-2 cups of fluid 30 minutes before exercise.
- Drink ½-1 cup of fluid for every 15 minutes of exercise.
- Replenish fluid lost (2 ½ cups for every pound lost during exercise).
- Keep drinking even after your thirst is quenched.
Water Versus Sport Drinks
For recreational exercisers (activity lasting 45 minutes) water is sufficient for hydration and does not add sugar or calories, making it a best choice for moderate length exercise sessions. Water is easily absorbed by the body, readily available and less expensive.
For workouts consisting of 45 minutes or more, for continuous, high-intensity workouts of any duration (running, aerobics, biking and intense weight training), or for workouts that follow a day of working outdoors, a sports drink may be beneficial in delaying muscle fatigue by providing your body with additional energy. For some people, the taste of a sports drink may help encourage increased intake of fluids.
Studies have shown that fluids containing electrolytes and carbohydrates are absorbed more quickly by the body. These studies show that fluids with electrolytes also help people to retain fluids after prolonged intense exercise.
How to Get a Personalized Answer
If you are concerned about your fluid intake, you can make an appointment to see a doctor at Student Health Services x4-4736 or x4-5058 (it’s free for SDSU students to see a doctor), or make an appointment at the ARC for a FREE nutrition counseling session (visit the ARC info desk). These resources can help you determine the amount of water/fluids that are best for you!