Nutrition During Exercise

Exercise depletes your body of fluid, carbs, and electrolytes. Nutrition During Exercise can re-supply your body with fluid and nutrients the longer you can prevent exhaustion. For workouts longer than one hour you may need to replenish your carbs and electrolytes along with proper hydration. For any workouts lasting more than two hours it’s absolutely necessary to ingest carbs and electrolytes along with fluid for maximum performance. Here are some basic guidelines you can follow to prevent the dreaded “Wall” of exhaustion.


Nutrition During Exercise

By far, the most important thing to remember when exercising is to hydrate properly. The rate of fluid loss can vary from individual to individual, but a good rule of thumb is to drink 3ml/kg of body weight every 15-20 min.

An average 160 lb person would have to drink 7 oz. of fluid every 15-20 min during moderate exercise to replenish average fluid loss. A 200 lb person would need about 9 oz every 15-20 min.

Fluid intake can rise under extreme conditions of heat and increased exertion. In such extreme cases the best way to be sure you are drinking enough water is by checking body weight after you exercise. If you train for endurance, get in the habit of weighing yourself before and after long workouts. You should have less than 2% weight loss during a workout.

A 150 lb person should never lose more than 3 lb over the course of a workout. Adjust your fluid intake accordingly.


All carbs are not created equal. Some simple sugars hit the blood stream within a few short minutes and more complex carbs take much longer to metabolize. The ideal situation is to ingest a mixture of fast and slow carbs in liquid form to refuel a depleted body. In doing this, you avoid a spike in blood sugar followed by the dreaded crash.

A typical athlete can only metabolize 30-60 mg of carbohydrates per hour. An elite athlete may be able to ingest up to 80-100 mg per hour but you are risking stomach cramps and gastric discomfort with more carbs. Start with a comfortable range and slowly increase the concentration until you feel discomfort to find your threshold.

Fast Carbs

  • Maltodextrin
  • Dextrose
  • Glucose
  • Sucrose

Slow Carbs

  • Honey
  • Fructose
  • Agave
Nutrition During Exercise


The four major electrolytes that maintain the body’s fluid balance are sodium, potassium, magnesium and calcium. They each play a specific role in hydration and cell function. Proper nutrition during exercise can refuel these depleted electrolytes.


Sodium is the most important electrolyte to replace during exercise. An average sized athlete can lose up to 800mg of sodium every hour in the form of sweat. It’s important to replace some of the sodium lost to prevent an electrolyte imbalance. Most athletes can only assimilate around 500mg of sodium per hour to avoid stomach discomfort. A typical 34 ounce sport drink will provide some sodium but read the labels to ensure you are getting enough electrolyte replacement. Too much sodium without the additional electrolytes can produce swelling of the hands and feet.


Potassium helps with intracellular hydration. It also works with the other electrolytes to assist with your body’s nerve impulses. A potassium deficit can lead to cramping and muscle break down. Most studies suggest potassium replenishment at a rate of 100-150 mg/hr.

Nutrition During Exercise


Magnesium contributes to red blood cell formation and the production of adenosine triphosphate (ATP). ATP is involved in the muscle contraction and energy production. A magnesium deficit results in premature fatigue, muscle cramps, anemia and nausea.


Less than half of athletes get the required amount of calcium. Low calcium levels can result in osteoporosis and hormonal imbalances. And excessive exercise can deplete the calcium stores to an alarming degree. A reputable mineral supplement can help boost calcium levels or by eating an abundance of fruits and vegetables is a great way to get proper nutrition during exercise.


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