Some of the most frequent and consistent questions we get at First Endurance have to do with how and what to use for fuel during exercise. If you have any questions or comments, we’d love to hear from you. Just comment below and we’ll make sure to get back to you right away.
Rocket Fuel for your Body- Glucose is always circulating in your blood and is the ‘rocket fuel’ for fast paced workouts or races. In fact, without glucose you are going nowhere fast. Your body can produce glucose in two different ways. The first, which also is the most efficient, is by utilizing the glycogen that’s found in your muscles and liver. This is a fairly fast and efficient method that can deliver a quick supply of glucose to fuel your workout. The downside is that we only have a couple hours worth of this stored glycogen at best.
The alternative option is for your body to convert non-carbohydrate sources like protein and fat into glucose. Even though we have days and days of fuel stored as protein and fat in our body, this option can be quite inefficient. Its important to know your pre-exercise glycogen levels and the pace at which you are exercising will determine what fuel your body uses. To a lesser degree your body’s own efficiency also determines what fuel is used.
Avoid ‘hitting the wall’- Your intensity determines whether your body utilizes fat or carbohydrates to fuel your workout. For an all-out sprint, your body will use glucose- the most efficient fuel to drive the working muscles. At a slower pace, or in a situation where you have burned your glycogen, your body will breakdown stored fat for fuel. Remember: your body has to convert fat to usable glucose in order to fuel the workout. It’s this inefficiency or slow rate at which your body converts the fuel source that causes you, or forces you, to only use this fuel during slow paced workouts. The dreaded ‘bonk’ is one of those times where you have run out of stored glycogen and you get the sensation of having no energy and being in an extreme state of exhaustion.
Teach Your Body a New Trick- The good news is you can condition your body to convert fat to glucose more efficiently. Not only will this increase your ability to go longer, it will reduce your need to take on additional calories during training and racing. This process uses a systemic method of training long distances on very little carbohydrates in order to train your body to burn fat more efficiently. This is the premise behind what is called ‘substrate utilization’ or ‘substrate training’ for long distance athletes. This is a significant benefit on race day because you’ll be more efficient at burning fat and sparing glycogen. This type of conditioning also allows you to consume fewer calories per hour, which often results in a decreased risk of gastric distress.
Fueling in Different Conditions: We’re talking primarily about temperature when we discuss fueling practices in different conditions. When it’s hot, your body expends a large amount of energy trying to cool itself by dissipating heat. It does this by circulating more blood to the skin surface so you sweat more. This leaves less blood to aid digestion AND you require more fluids to keep you sweating at a high rate. T
his high sweat rate is a sign of efficient cooling but does demand fluids and electrolytes in order to sustain workouts over many hours.
At First Endurance we recommend no more than an 8% solution during hot racing. An 8% solution equates to about 100 calories to every 12oz fluid. In cooler environments, where your body does not need to cool itself its easier to absorb and digest concentrations near 16%, or 100 calories for only 6oz fluid.
Be careful what you eat: Ingesting slow absorbing fuels like proteins, nuts, fats, foods with fiber and other solid foods during workouts can cause gastric distress as well a premature “bonk.” Slow absorbing fuels get stuck in the gut, which means your body can’t readily utilize them. If your body is burning stored glycogen as it waits for those slow nutrients to get absorbed, you’re reducing your 2 hour fuel tank and increasing your chances of ‘bonking.’ To reduce the chances of ‘bonking’ or gastric distress eliminate all slow absorbing nutrients from your fuel plan.
How to Use EFS for Any Distance:
Whether you are out for an intense high paced 45-minute workout, or about to embark on your 100-mile ultra distance run, EFS is designed to fuel your workout at any distance (based on a 150lb athlete).
< 2 hours COOL/COLD conditions: Consume 100 calories EFS per hour at a solution between 10%-16%. This means 100 calories for every 6-10 ounces fluid. Because high levels of electrolytes are not critical EFS liquid shot works well in this situation.
< 2 hours HOT conditions: Change to an 8% maximum solution. This means 100 calories to 12 ounces. If you are prone to cramping use EFS drink; for all others the EFS liquid shot will suffice.
2-5 hours cool/cold conditions: Consume 200 calories EFS per hour at a solution between 10% and 16%. This means 100 calories for every 6-10 ounces fluid. Electrolytes are still not critical, however due to the longer workout a mix of EFS drink and EFS liquid shot works great in this situation.
2-5 hours HOT conditions: Change to a 8% maximum solution. This means 100 calories to 12 ounces. If you are prone to cramping use EFS drink, for all others a mix of EFS drink and EFS liquid shot should suffice.
5+ hours COOL/COLD conditions: Consume 250-300 calories EFS per hour at a solution between 10% and 16%. This means 100 calories for every 6-10 ounces fluid. For very long distances your body will balance the use of stored fat, stored glycogen and orally administered calories to fuel the workout. Consuming only fast absorbing fuels assures that you deliver glucose consistently to the blood, which can help spare glycogen so you don’t bonk. A mix of EFS drink and EFS liquid shot works great in this situation.
5+ hours HOT conditions: Change to an 8% maximum solution. This means 100 calories to 12 ounces. At this caloric intake where a minimum 200 calories per hour are being consumed as EFS drink and the additional 50-100 calories per hour are being consumed as EFS liquid shot the vast majority of athletes should not need additional electrolyte support. A few of our pro athletes racing 8+ hours do like to use some additional salt in order to insure they do not become electrolyte deficient.