Fueling for (Distance) Running - Beginners Understanding
These subtle aspects can make all the difference in how you feel
If you have been following these newsletters for any time, you know Running has been a growing love of mine for the past couple of years.
Ever since crossing the Finish Line of my 100km (62-mile) trail race in April of ‘22, I been hooked. Being the guy who wasn’t any good at running my whole life, to finish a 62-mile race that I only spent 10 weeks training for was a mental unlock that I needed.
But if you recall, I struggled… badly.
I like to push my body to its limits. Part of that ideal is to see how I feel without proper fueling. (Newsflash, it’s not good)
It being my first year in Endurance sports at the time, I wan… no, needed to know what my body could handle.
But that thought process aided in developing my complacency or stubbornness around fueling for running at the time. So much so, 7 months after the 100km race, I walked 25 of the 26.2 miles of the Marathon at the end of the 140.6-mile Ironman.
It wasn’t until getting into the race season of ‘23 that I knew I had to dial in my fueling if I no longer wanted to race in excruciating pain.
But this path I chose led me to grow in understanding the minute details that need to be considered during endurance training and events.
One major realization is that Fueling for Triathlons is a lot different than Fueling for Running races. Especially Ultra-Distances (+26.3-miles).
First and Foremost hydration is of the utmost importance.
Like the planet we live on, 70% of the body is Water. Most of this water is inside our cells (intracellular). We lose water through Sweat, Urinating, Defecating, Breathing, and Blood Loss.
When we lose water we see a decrease in electrolyte concentration. This decrease can be seen in the physical effects such as:
0.5% body water loss = increase strain on the heart
1% loss = decrease in aerobic endurance
3% loss = decrease in muscular endurance
5% loss = Signs of Heat Exhaustion start to show
6% loss = Entering Heat Stroke/Coma territory
10-20% loss = DEATH
Why does the loss of water and therefore electrolytes have such an effect on us?
Sodium (Na), Activates muscle & Nerves, as well as influences H2O distribution.
Potassium (K), Regulates the cell’s response to stimuli, as well as regulates fluid in and out of the cell.
Magnesium (Mg), is involved in +300 Chemical reactions in the body and adjusts Muscle Response to Stimuli.
On average we see a Loss of electrolytes per 1hr Training:
1200 mg Sodium
140 mg Potassium
10 mg Sodium
Staying on top of hydration here will set you far ahead.
For this, follow these general outlines on replenishing water and electrolytes (per hour) of a run:
20-40 oz water per hour
500-1000+ mg Sodium
100-200 mg Potassium
10-20 mg Magnesium
Running for distance is usually a lower intensity than running for speed and the intensity of racing a triathlon.
This is key to understanding how to start fueling for runs.
Read most Sports Nutrition Literature on endurance sport fueling and you will see the recommendation of 60-120+ grams of carbs per hour.
Since it is lower intensity running promotes a ‘shaking’ of stomach contents consuming on the lower end of the spectrum is more ideal at first.
Taking in too much can ‘bog’ down the body’s ability to utilize the fuel you are giving it, which is the opposite of what you intend to do with the fuel.
For most athletes, starting with 50-75g of Carbs per Hour of Running is great.
That can come in liquid and/or solid form. From what I see works well is about 50g of carbs from liquid fuel and the rest from solid. When you push distance, solid fuel is going to help your stomach not feel so hungry throughout.
We’ll use Fats to a lesser extent, consuming 5-20g of fat per hour is helpful as your secondary fuel source. It is a slow-burn fuel so we rarely need to focus much on here. A solid food option should have plenty of fat for these reasons.
As runs get longer and longer, making sure we consume protein is vital. As we exercise we are breaking down our muscle tissue, and staying on top of our protein intake can help minimize the damage we are causing to the muscle. Consuming 20-30g every 4 hours is beneficial.
If you're a creatine supplementor, taking in 5-10g every 8-12 hours will help keep that small fuel source available so we’re not using endogenous amino acids within us to make it.
It’s important to help your body to adjust to using carbs and fats as fuel for runs. Part of this is understanding when you need to fuel and when you’d be okay just to hydrate on a run.
For most, lower-intensity runs that are aimed at base building lasting less than 75 minutes, fueling is not necessary. It might be a good idea to allow your body to learn how to use stored fuel for these activities.
For runs lasting over 75 minutes, it would behoove you to start fueling with the protocols above. Aiming for 50-75 grams of carbs per hour on top of the hydration aspect.
You’ll not only feel better during the runs, you’ll have an easier time recovering from them as well.
A thought to keep in mind, on long run days you’re not just fueling for that hour. You’re fueling for the next. Having achievable targets to hit will keep you aligned with your plan. Take small steps. TEST TEST TEST. Everyone will have different needs and if you want running to suck less, you apply these principles.