Nutrition and Endurance Training

Apr 16, 2019

This post is authored by Tara Geier. Tara is a 2018 graduate of the University of Massachusetts where she counseled collegiate athletes on nutrition. She is currently working towards her Master's Degree at College of Saint Elizabeth.

With longer days and warmer weather comes more endurance training and a variety of outdoor races. The definition of endurance training is “prolonged training at a relatively low intensity, aimed at enhancement of cardiorespiratory function, together with aerobic capacity of the exercised muscles.” While it’s so important to physically train for endurance races like marathons, half marathons, Spartan Races and triathlons, fueling yourself for these activities with proper nutrition is equally important.


Pre-exercise fuel has four main functions:

  1. Fueling before a workout prevents low blood sugar which can cause lightheadedness, fatigue, blurred vision, and indecisiveness.
  2. It helps settle your stomach, absorb some gastric juices and ward off hunger, especially early in the morning.

  3. Eating carbohydrates will help to fuel both your muscles and your brain.

  4. The peace of mind that comes from knowing your body is well fueled can help you to exercise harder. This also causes you to burn more calories, if your prime motive for exercise is to lose undesired body fat.

If you have a goal of weight loss:

Many individuals learn to exercise on an empty stomach with hopes of enhancing fat burning, but this may not be the most efficient way to reach their goals. To lose body fat, you need to create a calorie deficit by the end of the day. Fueling yourself will allow you to exercise harder, burn more calories, and therefore lose more body fat.

Fueling for endurance:

We know that pre-exercise snacks are important, but many people are afraid that eating prior to exercise will result in an upset stomach or cramping. Each person has different food likes and dislikes, so no one magic food or meal will offer the same benefits for everyone. Choices of what to eat before exercising varies between both the person and activity, and there is no one size fits all for nutrition. When it comes to endurance training, there are specific things we can work on to help you be better prepared for your next training session.

  • Take the time to practice your event-day fueling during your training period. A big part of your training is to create and practice your fueling strategies to be extra prepared for the race day. This is so important in order to figure out which foods and fluids work best for you during extended exercise. Lemonade or fruit punch sports drink? Gatorade or Powerade? Energy bars or a piece of fruit? Solids or liquids? By learning more about what works best for your body and your workouts, you won’t worry about making the wrong food choice on the day of the event.

  • Perfect your daily training diet. Often life gets in the way and between working, taking care of your family, taking classes, training and getting enough sleep making it difficult to plan, shop and prepare the right meals and snacks. When feeling extra hungry and tired it might be easier to pick high-fat comfort foods instead of making a more nutrient-dense meal. This comfort food choice will fill your stomach but will also leave your muscles unfueled for your training session.

    To work at the right intensity, you need to start your workout well fueled. If you start with low muscle glycogen, you will be unable to train at your best, and that means you’ll be unable to compete at your best. Your goal is to constantly be fueling before workouts and refueling after workouts with carbohydrate-based meals and snacks. By continuously feeding your body during the day, you will have steady energy without lags. Developing an eating strategy that fits your training schedule will not only set you up for success in your training, but also for the big day.

  • Stay hydrated. The most effective way to gauge your hydration is to monitor your urine each day. Frequent urination, around every three hours, clear urine and adequate quantity are all signs that you are hydrated. Morning urine that is dark is a sign of dehydration and your cue to drink more. When estimating your fluid needs for the race day, weigh yourself before and after an hour of event-paced exercise. For each pound lost from sweat, plan to drink at least 16 ounces of fluid while exercising to prevent dehydration during the event.  

  • Be flexible. Although you should have your set plan and know what works best for you, make sure to keep an open mind. Perhaps your initial plan is to consume whole fruits and energy bars during the race, but you might be craving potato chips and M&M’s later on. Listen to your body’s needs during the event and hopefully you’ll have the desired fuel available to get you to the finish line.

Refueling after endurance work:

Refueling yourself after your exercise greatly impacts your energy levels, just like fueling before exercise. During your training period, remember the importance of refueling and how what you eat after a workout affects your recovery. Right after exercise, our muscles easily

Right after exercise, the muscles easily assimilate protein from the blood and use it to build muscles. The muscles are also most efficient at absorbing carbohydrates from the blood to replenish depleted glycogen stores. Just like fueling, refueling is an essential part of your training program.

Quick Refueling Tips:

  • Carbohydrates release a hormone, insulin, that helps build muscles and transports carbohydrates into the muscles to replenish depleted energy stores

  • Carbohydrates combined with 10-20 grams of protein creates an even better response, and reduces the hormone, cortisol, that breaks down muscle

Effective Recovery:

The key to recovery is to consume three times more carbohydrates than protein. While most people may reach for a protein shake, it would be more beneficial to put together a fruit smoothie with some Greek yogurt. Or, enjoy a meal like pasta with meatballs or chicken with brown rice. Another top dietary priority for after exercise is to replace the fluids lost by sweating. This is so important because it helps our bodies get back into water balance. After exercise many people will grab a sports drink, but these are more effective to use during exercise as opposed to after. After a tough workout, recovery foods such as chocolate milk, a bagel with peanut butter, or pasta with tomato sauce will offer far more electrolytes than you would get from a Gatorade.

Sometimes signing up for a big race can seem daunting, but we hope you feel a little more prepared and set up for success after reading these tips. Best of luck on your next race.

O2 Fitness

If you are looking for a fitness network that will help you prepare for your next race, O2 Fitness is here for you. Our professionals are knowledgable, motivational, and experienced, so you can find the support you need to get on track. You can experience advanced training with our group fitness classes, advanced equipment offerings, and personal training sessions. Contact your local O2 Fitness experts to learn more today! 


  1. The Free Dictionary by Farlex. Endurance Training. The Free Dictionary website. Accessed March 25, 2019.

  2. Clark N. Nancy Clarks Sports Nutrition Guidebook. Champaign, Ill.: Human Kinetics; 2014.

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