How to Fuel the Long Run
So you're planning a road trip. What’s the first thing on your to-do list? If you’re like me (other than making sure I have some podcast episodes lined up), pretty high up on that list is making sure the gas tank (or battery, for us EV folks) is full.
It seems like common sense: to go a certain distance, you need to have the fuel to make it there. Our bodies operate the exact same way. Once this was explained to me, my fueling started to click—and my runs have continued to get better.
I struggled with fueling before and during my runs for the first couple of years, mainly from a lack of understanding the process itself.
Let’s keep it simple:
The way gas is needed for our cars to move, carbs are to us while we’re running or doing any aerobic training.
When we eat carbs, they are converted into glucose. If we don't use this glucose right away, it’s converted into glycogen and stored in our liver and muscles.
Think of this process as filling up your gas tank. So before we run, we want our gas tank (glycogen stores) to be full. This is why we want to eat carbs and sodium (for hydration) before we start our runs.
Back to the example: it doesn’t make sense to start a long car trip with a quarter tank of gas. When we don’t eat enough carbs or sodium before our runs, we are spending energy our body doesn’t have to give.
This is where the term “hitting the wall” comes from. The wall happens when our body’s gas tank is on E and our engine is starving and shutting down.
So yes, we want our gas tank full before we start—but the farther we go, the more of that tank gets used. This is where the importance of intra-fueling, or fueling during the run, comes in.
As we’re running, our bodies pull from our glycogen stores, turning that glycogen back into glucose, then burning it in our muscles as ATP—our direct fuel source to move.
If we can keep supplying our bodies with the necessary carbs to be converted into glucose and then ATP, we can run farther, run longer, and continue to push back the dreaded “wall.”
Intra-fueling becomes even more important as our distance goals grow. For me, it was the marathon distance and the training that came with it that really exposed my lack of fueling knowledge.
Going past the marathon distance into the ultramarathon world, intra-fueling becomes arguably the most important factor in the outcome of your race.
Intra-fueling takes some practice. Everybody is a bit different in what they prefer and what works best for their stomach. My preferred intra-fueling has been gels and liquid carbs with electrolytes.
To recap:
The human body truly is a machine—and it needs to be fueled properly in order to perform up to its true potential.
Before our longer training sessions, we need to fill up our gas tank with carbs for energy and sodium for hydration.
For longer sessions, we also need to be refueling our tank during the session to keep our body moving the way we want it to.
Finally, we need to refuel and rehydrate—especially with sodium and the other electrolytes we’ve lost through sweat—after our training sessions. This shortens recovery time and helps ensure we’re ready to tackle whatever else the day holds.
Like most things, fueling is something we can constantly be working on to improve. And the more we dial it in, the more effective our training becomes.
Intentional with our fueling, intentional with our training, intentional with our results.
Have a great week!
– GTY
