How Much Water Should an Athlete Drink?
Whether you are an avid exerciser or a competitive athlete, developing a proper hydration strategy can benefit your health and performance. Here are key things to consider.
Water is the most important nutrient for the human body. It’s required for every bodily process and just a 2% loss of fluid can negatively impact physical performance. A 1-3% fluid loss has been shown to impair mood, reduce concentration, contribute to headaches, impair working memory, and increase anxiety and fatigue. Let’s take a closer look at the importance and benefits of adequate fluid intake.
Why Adequate Fluid Intake Is Important
Adequate fluid intake can:
Boost energy and mental and physical performance
Support injury prevention
Improve circulation
Support healthy digestion
Improve the availability of oxygen and nutrients
Support joint lubrication
Help regulate body temperature
Support organ function and protect organs and tissues
Keep skin looking and feeling healthier
Flush out waste more efficiently
Support healthy weight management
Enhance longevity
Why is Hydration for Athletes Important & How Does Training Impact Hydration?
Exercise increases fluid needs, due to sweat production and increased losses through breath. Becoming dehydrated during exercise can:
negatively impact physical and mental performance
raise heart rate and body temperature
up the risk of nausea, vomiting, and other gastrointestinal problems during and after exercise
increase injury risk
General Water Needs Per Day
So, how much water should you drink? According to the Institute of Medicine, women 19+ need 2.7 liters of total fluid per day (over 11 cups) and men need 3.7 liters (over 15 cups).
About 20% of our fluids come from food, but that still leaves 8-12 cups based on the IOM’s guidelines, not including additional needs due to exercise.
How Much Water Should an Athlete Drink a Day?
Training increases fluid needs above what’s required during a sedentary day. Use the general needs listed above (women 19+ need 2.7 liters per day and men need 3.7 liters) as a starting point. Then, create a hydration strategy to meet your needs before, during, and after exercise.
When Should You Drink Water?
I generally recommend 8 cups of water per day as a baseline, spread evenly throughout the day. Think of your day in four blocks:
from the time you wake up to mid-morning
mid-morning to noon
noon to mid-afternoon
mid-afternoon to early evening
Aim for 2 cups (16 ounces) of water during each of these blocks. Set your cell phone alarm or use an app reminder if needed.
If you’re not a fan of plain water, spruce it up with healthful add-ins, like lemon or lime, fresh mint, sliced cucumber, fresh ginger, or slightly mashed bits of seasonal fruit.
Signs of Dehydration
Potential signs of dehydration may include:
thirst
dark urine
low urine volume
headache
weakness
dizziness
muscle cramps
nausea
decreased performance
Monitoring urine color can help assess hydration status.
How To Hydrate Properly for Sports and Exercise
To prevent both dehydration and over-hydration, it’s important to have a hydration strategy. General (non-personalized) rules of thumb for training hydration before, during, and after exercise are below.
1. How Much Water Should You Drink Before Exercise?
Drink 16-24 ounces 2 hours before training. Drink an additional 8-16 ounces 15 minutes pre-workout.
2. How Much Water Should an Athlete Drink During Exercise?
Drink 6-12 ounces every 15 minutes during exercise (plus carbs and electrolytes when needed).
3. How Much Water Do You Need After Exercise?
Post-training, replace every pound lost with 24 ounces of fluid, along with electrolytes if needed.
Should You Replace the Water Lost Through Sweat?
Yes, this is one of the most important aspects of your hydration strategy. This is why it’s valuable to know the amount of fluid lost during exercise.
Do I Need an Electrolyte Replacement?
If you sweat heavily, your workout lasts over an hour, or you’re exercising in hot and humid conditions, opt for a drink that provides electrolytes to replace those lost in sweat.
Sodium losses can vary, but in general, an electrolyte replacement should provide at least 110 mg of sodium per 8 ounces (along with smaller amounts of other electrolytes, including potassium and magnesium). It should also empty from the stomach just as fast as plain water. Sodium, the predominant electrolyte lost in sweat, encourages drinking, supports fluid absorption and retention, and replaces sodium losses.
Do You Need Carbohydrates in Your Fluids?
A sports drink that also contains carbohydrates may be helpful to fuel prolonged exercise, especially if you can’t stop to eat or if your appetite is diminished. If your sports drink contains carbohydrates, the concentration should be no more than 6 - 8% carbohydrate (about 14 - 18 grams per 8 ounces). Concentrations above this level can impair stomach emptying, lead to digestive upset, and impede performance.
Can You Drink Too Much Water?
Yes. Replacing fluid without an adequate level of sodium, or drinking more fluid than needed, can interfere with performance, and can lead to hyponatremia (diluted levels of sodium in the bloodstream). This is a dangerous condition that can cause disorientation, and in severe cases, coma, or death. Replacing sweat losses with fluid and electrolytes is crucial and to avoid water toxicity. Also, the CDC recommends not drinking more than 48 ounces of fluid within one hour.
Final Thoughts on Hydration Needs for Athletes
In short, aim for balance. The goal is to replace the fluid and electrolytes lost in sweat, so there is neither a shortfall nor a surplus. Athletes need to meet the recommended water intakes for adults, and strategically replenish additional fluids lost during exercise.
Consult with a sports dietitian for individualized guidance about the best ways to meet your own hydration needs.
More to Explore
Keep reading for more ways to optimize your fueling strategy for your fitness goals: