Hydration is one of the most crucial aspects of performance and recovery for runners. As both a physical therapist and avid marathon runner, I’ve seen firsthand how proper hydration can make or break a run. Here’s a guide to optimizing your hydration strategy, covering how much to drink, the balance between water and electrolytes, and when to hydrate.

Staying hydrated ensures your body maintains its blood volume, regulates body temperature, and delivers nutrients to working muscles. Even mild dehydration can lead to fatigue, cramps, and a decline in performance.

How Much to Drink

The amount of fluid you need varies based on factors like body size, intensity, duration of the run, and environmental conditions. Here’s a good starting point.

Daily Needs: Aim for at least half your body weight in ounces of water daily. For instance, if you weigh 150 lbs, aim for 75 ounces.

During Exercise: For runs under an hour, 4 to 6 ounces of water every 20 minutes is typically sufficient. For runs longer than an hour, 6 to 8 ounces every 20 minutes is recommended.

Water vs. Electrolytes: Finding the Right Balance

Hydration isn’t just about water. Electrolytes like sodium, potassium, and magnesium are essential for muscle function and to prevent cramping.

When Water Alone Is Enough: Short runs under 60 minutes. Cooler weather, where sweat loss is minimal.

When to Add Electrolytes: Runs longer than an hour, especially in warm or humid conditions. If you’re a heavy sweater (visible salt on clothes or skin post-run). After multiple training sessions in one day.

Electrolyte Sources: Sports drinks, electrolyte tablets, or powders. Natural options like coconut water or homemade electrolyte drinks (water, a pinch of sea salt, and a splash of fruit juice).

Timing Your Hydration

Before a Run: Hydrate throughout the day leading up to your run. Drink 16 to 20 ounces 2 to 3 hours before your run. Consume 6 to 8 ounces about 15 minutes before starting.

During a Run: Sip small amounts regularly instead of gulping large amounts sporadically. Adjust based on temperature and sweat rate.

After a Run: Replace fluids lost during the run. Weigh yourself before and after to estimate sweat loss; drink 16 to 24 ounces for every pound lost. Include electrolytes if you’ve had a long or intense session.

Hydration Tips for Long-Distance Training

Test Your Strategy: Experiment during training to figure out how much and what type of hydration works best for your body.

Use Your Long Runs: Treat these as dress rehearsals for race day, including hydration.

Carry Hydration: Use handheld bottles, hydration vests, or belts during long runs.

Hydration is personal and varies for every runner. By paying attention to your body, experimenting with water and electrolyte intake, and refining your timing, you can optimize your hydration strategy to improve performance and recovery. Remember, hydration isn’t just about what you drink during a run—what you do before and after matters just as much. Listen to your body, stay consistent, and enjoy every mile.

In the Department of Physical Therapy, Eric provides comprehensive care for patients who require treatment in all phases of physical therapy. He provides preventative injury education, conditioning, and training, as well as treatment and rehabilitation. Eric is an avid marathoner. He enjoys working with runners and endurance athletes and has had four children continue their running at the NCAA DI level.