Have you ever been working out and all of the sudden you feel like you’ve hit a wall?
Think about it ... You get to that point where you don’t want to move ... You feel like you can’t go any further ... And you feel like your body wants to give out.
If you've experienced this feeling, it's probably because you depleted your glycogen stores.
After all, your body is breaking down glycogen to use for energy during high-intensity training and resistance workouts. So, once it's out, it's no surprise that it can feel like you're out of gas!
You’re probably wondering, "how long do glycogen stores last during exercise?"
We’ll get into that. But first, it’s important to understand what glycogen is and how it’s made. Then, we’ll dive into your question: “how long do glycogen stores last during exercise?”
Let’s begin with what glycogen is!
What Is Glycogen?
Glycogen is basically the stored form of carbohydrates in our body. Well, not exactly, but I will explain this soon.
On top of that, there are two different places the body stores glycogen. Your body can store glycogen in muscle or in the liver (2).
Muscle glycogen is what your body will break down to utilize for intense exercise. Liver glycogen will actually be utilized when your body needs the energy or to help regulate blood sugar.
But, how exactly is glycogen made? Why do we have glycogen?
How Is Glycogen Made?
So, glycogen actually comes from glucose. However, glucose comes from carbohydrates found in the foods and drinks we have every day.
Here's how the process works...
When we eat or drink carbohydrates, our body breaks them down into glucose. From there, this glucose is released into the bloodstream for anything that requires energy at that time. Glucose is what fuels literally every single energy-requiring process in your body (1).
So, as you can imagine, glucose can be used for quite a few different things. After your body gets the energy it needs from this glucose, the rest is stored as glycogen.
Now, I know what you may be thinking ... "Carbs aren't stored as fat?" Well, they absolutely can be when glycogen stores are full. At the end of the day though, your body will only gain weight by consuming more calories than you're burning.
The purpose of stored glycogen is actually to serve as a fuel reserve. As I mentioned earlier, your body will dip into glycogen when it needs to for energy.
If we're considering how long do glycogen stores last during exercise ... This will depend on several factors.
How Long Do Glycogen Stores Last During Exercise?
When it comes to how long glycogen stores last during exercise, it depends. It depends on a number of different factors. Of those factors, these are the three I'd consider to have the greatest impact:
1. Workout Intensity
This is because when you are working out at a higher intensity, your body is depleting more glycogen (3).
For example, your glycogen stores will last longer if you go for a light jog versus sprinting! It’s the same thing with your gas tank.
If you’re cruising along at lower speeds, your gas tank will last longer than if you’re gunning it at 90 mph. Your glycogen stores are fuel for your muscles just like gas is fuel for your car.
2. How Conditioned You Are
Believe it or not, your current fitness level can also play a role in how long glycogen stores last. This is because people with improved physical fitness are able to store and use glycogen more efficiently (3).
Meaning, somebody who is a high-level athlete will have more energy readily available. For example, an olympic sprinter will use glycogen more efficiently than a sedentary person.
The athlete in this scenario would be like a person driving a fuel-efficient car, getting 30+ miles per gallon of gas. A sedentary person in this case would be like driving a bigger vehicle, getting 10 miles per gallon.
With training, your body can get more efficient when it comes to using glycogen.
3. How Much Glycogen Your Body Has Stored Before The Workout
The more glycogen that you have stored, the longer it can last during exercise (3). Now, this doesn’t mean that you should just go overboard with carbs right before your workout...
But, this does mean that getting enough carbohydrates can help make sure you're performing your best during your workouts.
Now that you understand all of that, how long do glycogen stores last during exercise? Is there a way to calculate or predict when it will run out?
Well, our bodies can store about 6.8g of glycogen per pound of body weight (5). So, knowing that everybody is built differently, it’s important to understand a few things.
The amount of glycogen that you can store will depend on different factors. These are factors like we discussed above. This is important because the more glycogen you can store, the longer it will last during exercise.
As a general rule of thumb, you can expect to burn 0.08 - 0.16 grams glycogen per pound of body weight every minute of all-out high-intensity exercise (3).
That means at an all-out effort, a 200 pound person could expect to last between 18.75 - 37.5 minutes!
I’m sure you can imagine how important it is to maintain glycogen stores too! So, how do you do that?
How To Maintain Glycogen Stores
Now that you know roughly how long you can expect glycogen stores to last during exercise ... How can you work to maintain your glycogen stores?
One easy way would be to lower your intensity of training. However, this is typically my last recommendation!
The actual best way is to make sure you're getting enough carbohydrates to replenish glycogen. To keep these stores full during training, it's recommended to eat or drink 0.54-0.68 grams of carbs per pound of body weight every 30 minutes (4).
A lot of people like to use quick digesting carbs like honey, fruit, and carbohydrate supplements. They do this so their body can break down the carbs quickly and release more glucose into the bloodstream.
For those of us who are really only exercising to look good and feel healthier ... Going out of your way to make sure your glycogen stores are full may not be worth the effort. For anyone who competes, whether that's in sports or any other kind of fitness event, it can be helpful to know.
Imagine going to run a marathon or do an ironman without the energy your body needs to cross the finish line. These would both be situations where it can be helpful to know!
How To Replenish Glycogen Stores
Replenishing your glycogen stores is all about what you do in the minutes, hours, and days after a workout.
This can look a little bit different depending on the type of exercise, the intensity of exercise, and many other factors too!
But, it tends to take at least 24 hours to get your glycogen stores mostly replenished (3).
The best way that I’ve personally found to do this is by adding Ignition into my post workout routine.
You see, everybody knows we should have protein after our workouts. But a post-workout carbohydrate is one thing that a lot of people miss out on. Ignition is exactly that!
It's a pure glucose powder, which your body can break down and use to replenish glycogen quickly.
That’s exactly why I use the Post Workout Stack after every resistance training workout. Oh, and especially after those all-out effort ones too!
The Post Workout Stack is a combination of our whey protein isolate, Phormula-1, and Ignition. Together, it's been the perfect combination for my recovery. I feel less sore, I recover faster, and it helps bring me back to life after those really tough workouts. Not to mention, I'm ready to get after it again much sooner.
But, I'd love to hear what you think too! The Post Workout Stack comes in a wide variety of incredible flavors, my personal favorite being Salted Caramel!
Plus, the Post Workout Stack also comes in a naturally sweetened version: The Natural Post Workout Stack ... as well as a plant-based version: The Vegan Post Workout Stack.
At 1st Phorm, we're committed to giving you the support and the highest-quality supplements to help you reach your goals.
With that being said, if there's ever anything we can help out with, don't hesitate to reach out!
We have a full team of NASM Certified Personal Trainers and Nutrition Coaches right here in St. Louis, Missouri. Just give us a call at 1-800-409-9732 or send us an email at CustomerService@1stPhorm.com any day from 6 AM to 10 PM Central. We'll be more than happy to help in any way we can!
References:
(1) Hantzidiamantis , Paris J., et al. “Physiology, Glucose.” StatPearls, StatPearls Publishing, 30 April 2024.
(2) Kanungo, Shibani et al. “Glycogen metabolism and glycogen storage disorders.” Annals of translational medicine vol. 6,24 (2018): 474. doi:10.21037/atm.2018.10.59.
(3) Murray, Bob, and Christine Rosenbloom. “Fundamentals of glycogen metabolism for coaches and athletes.” Nutrition reviews vol. 76,4 (2018): 243-259. doi:10.1093/nutrit/nuy001.
(4) Ivy, John L. “Regulation of muscle glycogen repletion, muscle protein synthesis and repair following exercise.” Journal of sports science & medicine vol. 3,3 131-8. 1 Sep. 2004.
(5) Acheson, K J et al. “Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man.” The American journal of clinical nutrition vol. 48,2 (1988): 240-7. doi:10.1093/ajcn/48.2.240.
ABOUT THE AUTHOR
