I would bet most people have heard this advice at one time or another. But what does this really mean? Where do these recommendations come from? In this post I’ll talk about the three states of hydration, help you find your daily fluid needs, and explain what electrolytes are and how to get them from food.

Hydration is important because the human body is made up of about 60-75% water depending on age. You are sufficiently hydrated when there is enough liquid in your body to reach all the tissues that need it to function normally.

Dehydration occurs when your body does not have enough fluid to function normally. This happens when you lose more fluid, usually from sweating, than you are able to take in. You are considered to be in a state of dehydration when you lose 2-3% of your body weight in fluid. This means that if a 130-pound girl loses more than 2 ½ pounds during exercise, she reached a state of dehydration during that workout. At a loss over 3% of your body weight, which for a 130-pound girl would be about 4 pounds, you can begin to see impairment in motor function and mental ability – meaning you will start to feel confused, uncoordinated, and fatigued.

How much do you need? On average you need about 30 milliliters (ml) of fluid per kilogram (kg) of body weight to maintain hydration. For most people this is around 2 liters, or the commonly suggested “8 glasses a day”. However there are many factors that can increase the amount of fluid you need. These include:

Weight

People who weigh more need more water. So while a 120-pound athlete needs just under 7 glasses of water per day, his or her 180 pound coach would need a little over 10 glasses to stay well hydrated.

Climate

Dehydration can occur in all types of weather. When it is hot you lose more water to sweat, and in colder weather you may not sweat as much but you will lose more fluid during breathing. Yes, you can lose fluid this way! The average person loses about 500 ml, or 2 cups, of water per day simply breathing. And according to one study, you can lose 42% more water, or almost a cup, when you breathe through your mouth instead of your nose. And in the middle of a 2K test or a 5K on the water, I’d bet most people are breathing through their mouth, at least by the end!

Altitude also increases fluid needs, and experts recommend those exercising at higher altitudes drink 3-4 liters of water per day.

Finding your needs

First, find your weight in kg by dividing your weight in pounds by 2.2. Then multiply that number by 30 to find how many ml of fluid you need. Finally, since 240 ml is equal to 8 ounces, divide that number by 240 to find how many ounces you need.

For example, if I weight 145 pounds, I would do the following:

145 lb ÷ 2.2 = 65.9 kg

65.9 kg x 30 ml = 1,977 ml

1,977 ml ÷ 240 = 8.2 glasses of water/day

Hydration for Athletes

The number you just found is the amount of water you need before accounting for exercise. During exercise, you will need to drink some extra water. For optimal hydration, and give your body time to get rid of any excess fluid, drink 2-3 ml per pound of body weight 4 hours before exercise. Try to drink 8 ounces of water 15 minutes beforehand, and then continue to drink during the workout. A good rule is to drink enough water so that you feel energized and avoid thirst, but don’t drink so much that you feel full. This usually adds up to around 8-16 ounces per 30-60 minutes of exercise. After training you will have lost some fluid and need to replace it. Generally, the recommendation is to weigh yourself before and after practice, and drink 24 ounces of water for every pound you lost. After a few practices you will get an idea of how much you normally lose, and won’t have to do this very often.

Electrolytes also play an important role in hydration. The most common electrolytes are sodium, potassium, chloride, and bicarbonate, and these help maintain fluid and electrical balance in the body.

Sodium regulates the total amount of water in the body and maintains the proper function of nervous, muscular, and other systems.

Chloride helps maintain a normal balance of body fluid.

Potassium is responsible for regulating heartbeat and muscle function and is important in neuron function. Extreme high or low potassium levels can cause irregular heartbeat, which can be fatal.

Bicarbonate maintains the right amount of acidity in the blood and bodily fluids. *This is important because muscle cramping is most often related to an accumulation of acid in the muscles.

When you sweat, you lose electrolytes in addition to fluid. Gatorade, and most other recovery drinks, have 100-120 mg of sodium, and the following foods have at least that much, if not more, in a common serving size: salted nuts and seeds, trail mix, deli meat, eggs, most dairy products, canned tuna, humus, olives, pickles, and raw or cooked spinach. Most sports drinks contain about 30-90 mg of potassium, but this electrolyte can be replaced by eating foods such as raw nuts, yogurt, milk (or chocolate milk), fish, sweet potatoes, tomatoes, beans, peaches, and melons. Most of the time, unless you are training for an extended period (greater than 90 minutes) or in very hot or humid weather, sports drinks are generally not needed to maintain hydration and electrolyte balance.

But…don’t overdo it! While it is important to maintain fluid balance and avoid dehydration, it is possible to become over hydrated. This happens when you drink significantly more water than is lost with sweat, causing sodium levels to drop. Your body likes things to be in a nice, balanced place, and when things get too high or too low your body will tell you. Low sodium levels usually mimic heat stroke symptoms, and let you know something is up with dizziness, headaches, nausea, irritability, and confusion. Over hydration happens primarily with endurance athletes (marathon runners or cyclists, for example) and as a power athlete your risk for this is not as high. But it is important to keep in mind, especially if you’ve been hydrating well in hot weather and still feel like you might have heat illness. If this happens to you, stop training, and have a sports drink or eat something salty.

Recipe of the Week  – Sweet Potato Latkes

I found this recipe through a Google search, so the credit goes to the writers of the “Everyday Paleo” blog. But since finding it, I’ve made it a few times (I love it as a post-morning workout breakfast topped with a fried egg or two) and it’s pretty easy and delicious. The recipe makes 12 latkes, but depending on how big you make them you’ll eat about 2-3 at a time and the rest can be covered and left in the fridge. They reheat well, and if I didn’t have time to make an egg, I’d just add a little almond butter and honey on top for breakfast.

Ingredients

5 cups shredded sweet potato

2 eggs

2 TB minced onion

1 tsp cinnamon

Salt and pepper to taste

Coconut oil

Directions

Mix all the ingredients together in a large bowl. Heat a skillet over medium heat and melt a spoonful of coconut oil.   Take small handfuls of the potato mixture and drop onto the skillet and press down gently into little “cakes”.  Cook for 3-5 minutes on each side or until the cakes are golden brown and crispy and the potatoes are cooked all the way through. Top with poached or fried eggs if desired.