What Is Glycolysis

You need energy to train hard and lift heavy. The carbohydrates you eat are broken down into glucose, which supplies you with energy to power your performance through a process called glycolysis. We’re going to discuss what glycolysis is, the science, how it works and the role it plays in your training.

What Is Glycolysis

According to the National Institute of Health (NIH), glycolysis is a process in which glucose, is partially broken down by enzymatic reactions that do not require oxygen. Glycolysis is one method that cells use to produce energy. Because glycolysis does not require oxygen, it is the first step in anaerobic respiration [R].

How Does Glycolysis Work

Let’s talk basics. Think of glycolysis as having two phases. Phase one, the, “investment” phase consumes two ATP molecules. The second, the “payoff” phase produces four ATP and two NADH and two pyruvate.

Therefore, glycolysis consumes two ATP molecules, producing four ATP, two NADH, and two pyruvates per glucose molecule. The pyruvate can be used in the citric acid cycle or serve as a precursor for other biological reactions [R].

Glycolysis occurs in both aerobic and anaerobic states. In cells that use aerobic respiration as the primary energy source, the pyruvate formed from the pathway can be used in the citric acid cycle. It then goes through oxidative phosphorylation and converts into carbon dioxide and water.

In anaerobic conditions, pyruvate converts to lactate through anaerobic glycolysis. 

How Does Glycolysis Affect Exercise

During strenuous exercise, your muscles lack oxygen supply, which produces lactic acid through glycolysis and releases energy for ATP resynthesis. This is known as the anaerobic pathway of energy metabolism.

Without oxygen, the body relies upon adenosine triphosphate (ATP) and glucose or glycogen in the muscle cells for energy, comprising what’s called the phosphagen (immediate) energy system and glycolytic pathway to produce energy in limited quantities.

When exercise intensity increases the glycolytic system is in full force and the mitochondria are trying to keep up with the amount of pyruvate that is being produced. This process leads to the conversion of pyruvate to lactate (lactic acid), which can take anywhere from 10-90 seconds depending upon workout intensity, producing a significant number of H+ (hydrogen ions) which are expelled into the bloodstream. When you’ve reached this type of exercise intensity, your body can’t keep up for long, resulting in muscle fatigue and a loss of power.

What Is Glycogen Resynthesis

As we’ve explained, the process of glycolysis utilizes glucose for energy during anaerobic exercise, resulting in pyruvate, and lactate. As lactate enters the muscle tissue, a burning sensation occurs, resulting in a loss of power and muscle fatigue. But what about the process of replenishing the expended glucose during exercise. This is called glycogen resynthesis.

Glycogen resynthesis is the biological process of replenishing glucose and glycogen after exercise.

Several studies have identified that muscle glycogen is a major determinant of endurance exercise capacity [R]. Optimal nutrition strategies, prioritizing carbohydrates to manipulate and store muscle glycogen, will result in better athletic performance and recovery. Carb loading is often used as a training strategy for endurance athletes to replenish glycogen stores for prolonged endurance capacity and training.

However even in the absence of post exercise carbohydrate intake, glycogen resynthesis occurs at a lower rate through gluconeogenesis [R], particularly in the case of high-intensity exercise, lactate [R] The highest rates of resynthesis occur with postexercise carbohydrate and is the most important determinant of muscle and glycogen synthesis.

RELATED ARTICLE How To Carb Load For Better Performance

Carb loading strategies vary in characteristics from athlete to athlete, regarding type of carbohydrates and the intensity and duration of activity or training, which will determine the carb-loading period. Having versatility in carb loading strategies, allows greater flexibility in pre-competition prep. Carb loading strategies should exceed 8-10g per kg of lean body mass [R]. Carb loading can last and store muscle glycogen content for up to 5 days, when loaded at maximum levels. 

Supplementing with carbohydrates during training, or on race day, will ensure delayed muscle fatigue, and promote better endurance and long-lasting sustained energy. By supplementing carbs intra-workout, you’ll have a better chance of overcoming your wall. Intra-workout carbs provide a rapid uptake and fuel source to improve performance. Energy gels, chews, and electrolyte drinks with higher sugar content will provide a short burst of energy, which can be extremely beneficial on race day. Complex carb drinks, such as Swolverine’s Clean Carbs, is also the perfect intra-workout carb source, to help provide energy to overcome the wall of fatigue. Unlike nearly all other carb sources, which use simple sugars like maltodextrin, and dextrose, Swolverine's Clean Carbs® are made with 100% real whole-superfoods from complex carbohydrates, including Sweet potatoes, Yams, Oats, and Blueberries. These four ingredients provide the long-lasting and sustained energy your body needs to fuel performance and optimize recovery.

RELATED ARTICLE Should You Take A Carb Supplement?

What Is Glycolysis: Takeaway

Glycolysis is the first step in anaerobic respiration, generating energy in the form of ATP from carbohydrates and glucose in your blood stream during strenuous exercise or resistance training. During glycolysis, your body generates pyruvate and lactate or lactic acid, which causes a burning sensation, resulting in muscle fatigue and a loss of power. If you can buffer this lactic acid burn, you can effectively increase workout volume, translating to better performance, strength, and gains. Beta-alanine is one of the only supplements that can aid in buffering lactic acid, to help you prolong exercise capacity and get better results.

Need Help With Optimizing Your Diet And Nutrition Plan To Finally Get The Results You've Been Waiting For?

The Swole Kitchen is an exclusive membership opportunity for those who are looking to pursue a performance-driven lifestyle. By combining wellness consulting, nutritional lifestyle improvement, and 1:1 customized nutrition plans to our members, our programs aim to optimize human potential. In each of our programs, you’ll receive guidance to reclaim your health, fuel your lifestyle, and pursue performance ambitions, all while learning how to make nutritional decisions from a place of self-trust and intuition. All of our coaches are committed to providing the highest level of results-driven wellness to our members.

We believe that everyone can optimize not only their athletic performance but their human potential. The way we believe we can optimize performance is through transparency, clinically effective doses, and clinically proven ingredients with evidence-based outcomes. We provide the nutrients you need to power your active lifestyle.


Walter Hinchman

Walter Hinchman

Walter Hinchman is the Founder and CEO of Swolverine. He is a NESTA and ACE certified trainer and holds a Masters Degree in Business and in Finance and Economics.


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