The 1st Hour: Setting your body up for the Next 5, 10, 20 or more Hours of Endurance exercise.

The 1st Hour: Setting your body up for the Next 5, 10, 20 or more Hours of Endurance exercise.

At SFuels, we’ve been advising a unique approach to fuel athletes in training and racing, since the day we opened our doors. We formulated specific fuels and products for the changing physiology from rest, aerobic intensity, to high-intensity training and racing. Furthermore, we frontiered the practical application of the timing of substrate-fuels for maximum training adaptations, and called it - the RIGHT FUEL RIGHT TIME method.

So what’s the rationale?

Well, much changes in our energy-processing physiology between sitting on a couch and after an hour or so of aerobic exercise.  It’s commonly assumed, that how our body moves glucose out of the blood and into the muscle cells, is a singular and fixed process at rest, and during exercise. But it’s not at all true. In a high-level summary - here’s what actually happens.

At rest, when we drink some juice, or any form of carbohydrate, (particularly simple sugars, like sucrose, glucose, fructose, maltodextrin) sugars are rapidly absorbed into the bloodstream, and then move through the liver.  These sugars (glucose), then trigger our pancreas to produce and push insulin into the bloodstream.  By design, insulin will interface with muscle cells and trigger them to open up glucose channels, allowing glucose to flow into the muscle cell. Conversely, insulin also informs fat cells NOT to oxidize or breakdown fat for energy.

Now, let’s look at what happens during exercise. Repeated muscle contractions  release chemicals like Calcium, nitric oxide, and free-radicals. While still being researched, it’s thought that these chemicals are responsible for triggering the movement of cell-transporters (namely, Glut-4) inside the cell, to move to the edge of the muscle cell, and open up glucose channels, allowing glucose to flow into the cell – without insulin.  The intensity of the muscle contractions, is a key determinate factor in the speed of movement of Glut-4 to the cell edge, the opening of glucose channels, and the speed of raising glucose levels in muscle tissue. 

At this point, you now have a physiology, whereby the muscle cell is optimized to simultaneously transport and oxidize both glucose and fat (fatty acids) substrates inside muscle cells for fuel. 

But, here’s the issue – For the past 30 years of carbohydrate-led fueling guidance, athletes have been asked to start taking carbs, the night before, the morning of, at the start of the race, and through the race.  As underlined above, any intake of carbohydrate, will raise insulin, and instruct the fat-oxidation machinery to switch off.  This effectively blunts your physiology, making the athlete far more dependent on carbohydrate stores and intakes to perform best in their training and racing.  In this 2021 study, (Rothschild et. al.) it was demonstrated how pre-training carbohydrate intake blunts fat-oxidation efficiency during training. The study also highlighted that taking protein/fat pre-training had no negative effect on fat-oxidation or performance during training. 

Practical Application 

1) Avoid pre-training carbohydrate intake in the 3-4 hour period before your workout, to minimize insulin rises and fat-oxidation blunting pre-training. Take some fat-protein, like SFuels LIFE Bar to feel satisfied and energized going into the workout. 

2) Taking water or, SFuels ZONE 2 or SFuels TRAIN (no carbohydrate) in the thirty-sixty minutes prior to training will help support rapid movement of Glut-4 transporters to the cell-edge for insulin-independent glucose transport into the muscle cell.  

Download our GET STARTED GUIDE, for the practical application of implementing the RIGHT FUEL at the RIGHT TIME for aerobic, and higher-intensity training and racing.

This is highly relevant for athletes to perform at their best in both high-intensity training sessions, or during racing.

To make this super simple for you, take a read of our Training Guide Recipes - DOWNLOAD HERE 


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