A couple of hot topics in the sport nutrition world lately relate to fluid and electrolyte needs for athletic individuals (no matter whether recreational or more elite in abilities). I want to address a few issues related to hydration in this article, some of which have also been questions previously posed by KRE teammates.
Fluid and water recommendations for athletes have run the gamut in the context of daily needs and needs during exercise. As an example of this, check out the following list of recommendations that have circulated in recent years:
8 x 8-ounce glasses of water daily
Drink 1/2 of your body weight in water daily
Drink fluids until your pee is clear in color
Drink fluids until your pee is pale in color
Males: 15.5 cups of fluids;
Females: 11 cups of fluids (Adequate Intake as set by the Institute of Medicine for healthy 19-70+ year-olds)
0.154 to 0.185 ounces of water per pound of body weight during exercise
3 to 8 oz of fluid every 15 minutes during exercise
Drink ahead of thirst
Drink to thirst
Which one is right? The short answer is: none of them have been proven scientifically to be the “one and only way” for all healthy athletic individuals. What it really gets down to is figuring out what YOU need. Like most things when it comes to being an athlete, right?
Before I present some hydration tips, let’s review some of the important benefits of hydration:
1. Aids in digestion and absorption of nutrients from the food we eat
2. Necessary for proper bodily organ function and elimination of waste products
3. Helps with cognitive function
4. Promotes bowel regularity
5. Involved in regulation of core body temperature
6. Delays fatigue
7. Important for skin health
8. Supports athletic performance
Now that you have a brief refresher as to the various roles of hydration, here are my suggestions and notes regarding daily and exercise hydration:
Day to day fluid intake: Drink water and other fluids (such as teas, coffee, unsweetened cow or alternative milks, mineral or seltzer waters) throughout the day, but don’t force it.
It is okay to monitor urine color and frequency, but know that certain vitamins, supplements, and foods can alter urine color. You can reference the chart below (from the Nutrition Working Group of the International Olympic Committee) as a general guide to your hydration status.
There are a number of vegetables and fruits that contain a high water content. Examples are tomatoes, bell peppers, cucumbers, leafy greens, celery, zucchini,strawberries, peaches, watermelon, and oranges. You do not have to rely on
drinking plain water to increase your daily water intake, which is yet another benefit to having a variety of vegetables and fruit in your daily routine!
The mantra of “drinking to thirst” is ideal, but in reality, we all have many distractions and often let our behaviors get in the way of recognizing thirst and honoring thirst.
Aiming for weight loss? There are some research studies that suggest drinking 16 oz of water prior to main meals, along with a calorie-restricted diet, can aid in weight loss in overweight adults. We also know that replacing other sweetened beverages with water reduces daily energy intake, which technically should promote weight loss.
Exercise-related fluid intake: Ideally, we begin our exercise in a well-hydrated state (reference the urine color chart as a guide). However, this can’t always happen, especially if we must do early morning workouts. If you are unable to drink much water in the morning prior to a workout, you can opt to drink water during the workout or at least, make a point of rehydrating afterwards. A general rule of thumb is to drink 16-24 oz of fluid for every pound of body weight that is lost during exercise. Note that this requires you to weigh yourself before and after workouts. Some sodium in a post-workout beverage can help with fluid absorption.
During exercise, it is essential to avoid forcing fluid intake. The notion of “drinking before you feel thirsty” is old school thinking. The main concern here relates to the potential risk for water intoxication, or onset of exercise-associated hyponatremia, which has serious health implications. Instead, drink fluids as you feel thirsty. I recommend keeping a hydration log after key workouts so that you can begin to track average intake, changes in body weight from pre- to post-workout, and how you felt during the workout. In general, I recommend no more than 24 oz of fluid per hour but this will vary depending on individual thirst, sweat rate, and stomach tolerance.
Electrolyte supplementation is typically not needed for any workouts less than 75 minutes in duration.For exercise lasting over 90 minutes in duration, you can consider a carbohydrate-containing beverage (with 3-4% carbohydrate content). Good formulas are: Skratch Exercise Hydration Mix, Osmo Hydration, or Clif Shot Exercise Hydration Mix. There are various other electrolyte formulas that do not contain calories, but this will be discussed in a future article, along with sodium needs for athletes.
Just as overhydration is a concern, hypohydration (or dehydration) can be concerning. This is an area of controversy: how much dehydration can we experience during exercise without performance being compromised? Some
experts will say up to 10% dehydration while other experts say in the range of 2-3% is acceptable.
If you are doing two workouts in a single day, it is especially important to pay attention to your hydration so that you adequately rehydrate from the first session and prepare for the following session. Also, if you have a quality workout session planned for the next morning, try to think ahead so that you are not extremely dehydrated the next day. Alcohol consumption often gets in the way of proper hydration!
Hopefully these tips will help you check on what you are doing with daily fluid intake and during your exercise and training routine. Hydration is another underappreciated area of health and athletic performance. Should you need some individualized assistance, please don’t hesitate to contact me.
Dina Griffin, MS, RD, CSSD, METS II
Board Certified Sport Dietitian