Wednesday, April 21, 2010

Fueling for endurance exercise. Part I: Fueling during the exercise

Whenever exercise lasts longer than 60 to 90 minutes, it is definitely wise and extremely helpful to fuel up during exercise. There are a lot of different points to consider; however, first and foremost, know that finding just the right combination of “fuel” depends on you. While there are general guidelines to follow, everyone tolerates liquids and foods differently during endurance exercise. For this reason, you must experiment! Once you have found one or several combinations that work for you, stick with those when it comes to the day of your event. You never want to try something new when you’re trying to perform your best!

1. After the first hour of exercise, the American College of Sports Medicine (ACSM) recommends consuming 100 to 250 calories every hour. This snack should contain about 30 to 60 grams of carbohydrate. The part that varies here is, a. what you eat, and b. how you spread it out during an hour. You don’t have to eat a snack all at once, but you can if you want! Also, this can be in the liquid form, i.e. Gatorade, Powerade, etc.

While extended exercise does lead to the breakdown of fat for energy, your body runs more efficiently on glucose. Consuming carbohydrate while exercising gives your body quick energy to improve performance and generally feel better. Come back next week for a list of ideas for snacks during endurance exercise

2. Although fueling is important, be very careful not to overdo it. Too much sugar can have a negative effect by slowing how quickly food leaves the stomach. Also, too much of anything during endurance exercise could cause gastrointestinal distress.

3. It is imperative to drink fluids during prolonged exercise. A couple of keys are:

a. You should be sipping throughout exercise, not gulping at the end. Taking small sips here and there keeps you hydrated and energized, while a large amount of water at one time can upset your stomach during or after exercise.

b. Sip moderately. Yes, it is true that you may not feel thirst until you’re already under hydrated, but be aware that you can over hydrate. This is extremely dangerous and can result in death. No need to be scared! Just don’t down more water than you are thirsty for. Listen to your body. This is also another reason to be eating snacks with electrolytes, which are important to “balance out” the water that you are drinking.

c. Weigh yourself before and after exercise. For every pound you have lost, you need to drink 16 ounces of fluid. This can be a guide for your next workout too if you’re unsure of how much you should be drinking.

d. Check your urine. A dark color can mean that you are still under hydrated.

For further reading, I highly recommend Sports Nutrition Guidebook by Nancy Clark, MS, RD. and Nancy Clark's Food Guide For Marathoners by Nancy Clark, MS, RD.

**Be sure to come back and visit on Friday! I am excited to bring you a post from a very special guest!**


  1. This is quite helpful. I'm looking forward to the snack ideas.

  2. Very helpful. Also looking forward to the snack ideas and your special guest.