Nutrition During Endurance Events & Activities

Posted 29 June 2018 by Maria Stadelman, ACSM EP-C

‘Tis the season for outdoor endurance sports! Before heading out, we make sure we are equipped with the finest apparel, shoes, headphones and playlist, but what about nutrition? Our bodies need to be fueled with carbohydrates, fluid and electrolytes along the way, especially for activities lasting longer than an hour. 

Muscle Glycogen

What is it?
During exercise, muscle glycogen is used as our source of energy as our oxygen consumption increases—i.e. heavier breathing leads to increased muscle glycogen uptake. The rate at which it depletes is a direct relationship to how intense our activity is—higher intensity, quicker depletion. Topping off those stores by eating a meal 1-4 hours before your activity or event is beneficial; however, it may not be enough to sustain you throughout the course of your exercise. Based on a significant amount of research, The National Strength and Conditioning Association (NSCA) has set guidelines to help athletes reach their highest potential. Carbohydrates, electrolytes and fluids are the main focus when it comes to fueling before and during a race or training session. Protein should be included, but at a minimal level. Fats and fibrous foods should be avoided immediately before and during a race or training session, but are needed after and important in general daily nutrition. 

Hydration and Electrolytes

What is dehydration?
Hydration is also a large part of nutrition that can easily be forgotten until it is too late! Being hydrated means your body is at a level of sufficient total body water. Dehydration is where your body is actually in the process of losing water and is the most dangerous state. This is NOT a steady-state, and will quickly become detrimental as it continues to decrease. Studies have shown that in ALL environmental temperatures, prolonged restriction of fluid during exercise can increase internal body temperature, increase heart rate, and decrease overall performance. 

How do I avoid dehydration?
In events or training sessions lasting longer than 45 minutes to 1 hour, we know that we need carbohydrate as fuels. For those carbohydrates and electrolytes to work properly, they need to be digested with a fluid. If you have a constant intake of fluid and electrolytes, there will be constant absorption of those nutrients, thus, you will be sufficiently hydrated and balanced! More specifically, sodium (salt), potassium, magnesium, and chloride are the top electrolytes that are lost in sweat during activity. These need to be replaced and kept in balance to avoid cramping, lightheadedness, heat exhaustion, heat stress, and heart irregularities. The best way to do this is through your hydration method. There are numerous products you can add to your water to get these electrolytes. There are also product options where you can get all three at once; fluids, electrolytes, and carbohydrates. It’s important you find one that works best for YOU and your body’s needs. 

Hydration Stations During Races and Training

PLAN PLAN PLAN! There is a reason there are an excessive amount of hydration stations during sanctioned race events. Be sure you are aware of what mile they will appear, and what will be available (for example, bananas, gels, water, Gatorade, orange slices, etc.) PLAN ACCORDINGLY! Before the start of the race you should know at what minute you will be re-fueling, at which station you will grab something other than water, and what you will do if one of your previously planned options is no longer available. The same goes for your training sessions! Indoor or outdoor, you should make sure you have enough fluids/carbs/electrolytes with you or available to you when needed. Personally, I am not a fan of carrying a water bottle, so I make sure I pass through the park, run by my house or run near a drinking fountain at the time increments I know I will need it most. I have been known to hide mini water bottles on a long running route before I set out on my run, so they are there for me when I pass by.  

This table shows the recommendations of nutrition before, during and after your endurance activities. Note the different activity lengths. A good rule of thumb is to re-fuel with carbohydrates, fluid and electrolytes every 45 minutes. You want to be ahead of your nutrition game before you have to start playing “catch-up”. Also note the guide is in “grams/pound”. This means, you need that many grams per pound of your body weight. 

Fueling your body properly is not only important for an athlete to be able to perform at his or her best, but it is essential in order to get the absolute most out of training. Without it, training sessions end early or are completed at a lower intensity than the athlete’s physical potential. A proper training plan does not stop at mileage or time; it also includes nutrition “practice” to find out what your body can tolerate before, during and after exercise bouts. Enjoy the beautiful weather and remember to stay on top of your nutrition BEFORE your body tells you to! 

Come talk to me or any of the fitness staff for additional details and information!