Information, Symptoms, Treatments and Resources


What to Eat and Drink During a Cardio Workout


Exercise nutrition and hydration advice

By John Hoeber, MS, RD, CSSD, CPT


Eating the right amount of food can make or break a workout — but it’s not always as important as you might think. If you’re on a weight-loss or low-carb diet, your workout is more than an hour, or you’re doing two workouts a day, it’s very important to eat before and even during your exercise. On the other hand, if you’re doing a light workout, lasting an hour or less, you can stop reading right here and head out the door, as long as you’ve eaten well during the day.

Fluids are crucial for everyone, however. If your workout is less than one hour, plain water is the best choice, but if you exercise for more than an hour, choose a drink with electrolytes and carbs. You should eat between 30 and 60 grams of carbs per hour (0.7 grams per kilogram of body weight) when exercising for more than an hour, and enough fluids and electrolytes to keep up with losses from sweat and respiration.

Coconut water is a natural beverage with a near perfect balance of carbs and the key electrolytes: sodium and potassium. It’s also isotonic, meaning it has a solute concentration similar to your body's cells, so your body absorbs it more easily than most sports drinks. Coconut water contains a small amount of protein (5:1 carb to protein ratio), phytonutrients and some key vitamins and minerals that are important to athletes — one liter has 25 to 30% of the Recommended Dietary Allowance (RDA) for vitamin C and 60 to 75% of the RDA for magnesium.

The concentration of sugars in coconut water is around 4%, which is perfect for low intensity exercise such as hiking, but a little low for very intense exercise. You can increase the sugar content by adding 2 tablespoons of sugar to a 24-ounce bottle for a total of 50 grams of carbs. Plan on drinking one bottle per hour.

If you prefer sports drinks, look for ones that have 6 to 8% carbs, about 2 grams of sugar per ounce. When it comes to electrolytes, ideally you want twice as much potassium as sodium. The concentration should be 15 to 20 milligrams per ounce for sodium and 30 to 40 milligrams per ounce for potassium. A glucose gel or shot paired with an electrolyte drink is a good option. Try to get 30 to 60 grams of sugar per hour of exercise. To stay hydrated, it’s best to calculate your sweat rate and plan on taking in an equal amount of fluid.


Recipe: Refueling During Your Cardio Workout

  • 8 to 16 oz plain water or coconut water for workouts lasting 1 hour or less
  • 24-oz bottle of coconut water with 2 tbsp sugar added for workouts lasting more than 1 hour. Have another 24-oz bottle for every hour of exercise thereafter


Other Ideas:

(Each contain 30 to 60 g carbs)

  • 1.5 ­to 2.5 packets of GU Energy Gel
  • 2.5 to 5 packets of Cliff Shot Gel
  • 1 pouch of 10 Cytomax Energy Drops
  • 1 small to large baked potato
  • 1.5 to 3 single-serving cups of applesauce*
  • 1 or 2 large bananas*
  • 16 to 32 oz Cytomax or Gatorade Endurance Formula

*Fruit sugar is not ideal


Published October 24, 2014. 


John Hoeber helps people improve their health and athletic performance through diet, using practical and lasting solutions. He is a registered dietitian, certified specialist sports dietitian, personal trainer and wellness coach with more than 26 years of experience. Contact him at


See also:  

Explore More In Our Hep C Learning Center
image description
What Is Hepatitis C?
Learn about this treatable virus.
image description
Diagnosing Hepatitis C
Getting tested for this viral infection.
image description
Just Diagnosed? Here’s What’s Next
3 key steps to getting on treatment.
image description
Understanding Hepatitis C Treatment
4 steps to getting on therapy.
image description
Your Guide to Hep C Treatments
What you need to know about Hep C drugs.
image description
Managing Side Effects of Treatment
How the drugs might affect you.
image description
Making Hep C Treatment a Success
These tips may up your chances of a cure.