Fueling on the Run: Shorter Runs and Workouts
The mid-run fueling discussion is often saved for marathoners or runners who do very long training runs, because these are the scenarios where we could actually hit the wall — the dreaded “crash” or “bonk.” (This is when the body runs out of muscle glycogen. Read more about the specifics here.)
HOWEVER!
Runners of all distances can benefit from a hit of sugar during a workout or shorter run, even if there’s no danger or bonking.
The Brain Connection
Fueling during the run helps performance because the brain is getting signals as we eat that fuel is coming!
When the brain detects sugar in the mouth it will allow the body to work harder, and can even lower perception of effort (how hard the workout feels). Because this is a neurological effect (the brain signals to the body) it doesn’t actually matter if the carbs in the mouth are ingested. The carb beverage (or gel, chew, candy, gatorade, whatever it is) just has to be in the mouth for a few seconds to get the neurological benefit.
Just like you’d swish mouthwash around then spit it out, you can swish a carb beverage for a few seconds and spit it out. This is called Carbohydrate Mouth Rinsing. The study done to demonstrate this performance benefit had the participants swish for 5 seconds. (You can read extensive information about carb rinsing here.)
Carb Rinse - What’s the Point?
You may ask why would anyone want to spit out their fuel? Isn’t that gross?
Well, I think ideally you could swallow it down but sometimes during a hard effort the stomach is a little bit upset.
Importantly, the carb rinse demonstrates that the brain will allow the body to work harder when it detects sugar —and this is a separate process than carbs being used as fuel. So it doesn’t really matter if you’re doing a short workout and are in no danger of bonking, if your brain detects sugar in the mouth, you’re going to feel the positive effects. And it doesn’t really matter how much you’re able to get down.
Recovery Kick Start
Fueling during the run helps speed up recovery from a workout because while the body uses up our stores of glycogen, they are being replenished. When the workout is over the body won’t be as depleted as it would have been without eating during your workout. (It’s still important to consume carb and protein soon after a session to accelerate recovery.)
Try It Out
The first time I tried mid-run fueling was very memorable. I ate a half a gel during a hard effort “long” run (about 90min). I didn’t physically feel better or try to increase my effort but my pace dropped significantly! Seeing the splits get faster and faster was really fun.
After that I always brought a jolly rancher for my hard long runs, and gatorade to sip on between intervals in a workout. On the long runs, I’d eat the jolly rancher about halfway through my long run. Since it’s a hard candy it took a long time to dissolve which meant it was in my mouth for a long time, signaling to my brain that sugar! is! here!
Please note: one single jolly rancher does not have enough carbs to help with the recovery aspect discussed above. I used it for the performance benefit.
Hard Efforts Only
To be clear, I’m not encouraging runners to bring gatorade or gels or candy on their easy 40min run. It’s really unnecessary to maximize performance and recovery for easy efforts.
But if you bypass the aid station on a 10k race course, you’re probably missing out on a performance benefit! I encourage my athletes to sip gatorade between intervals during workouts, and bring candy, a gel or gummies for harder efforts on the roads like a tempo run or progression run.
To dial in on your individual needs or for more information of any of these topics, I highly recommend consulting with a Registered Dietitian.
Nicole Sifuentes is a full-time Running Coach for adults of all ages and abilities. She is a former professional runner and 2-time Olympian, and Certified Strength and Conditioning Specialist. Read more about her services, and schedule your free coaching consultation.