How long does glycolysis take

By about 30 seconds of sustained activity the majority of energy comes from the anaerobic glycolytic system. At 45 seconds of sustained intense activity there is a second decline in power output. Exercise beyond this point has a growing reliance on the aerobic energy system, as the anaerobic glycolytic system starts to fatigue. There are four key steps involved in the anaerobic glycolytic system.

Steps of the anaerobic glycolytic system:. This results in pyruvate binding with some of the hydrogen ions and converting them into a substance called lactate completely different to 'lactic acid'. Lactate acts as a temporary buffering system to reduce acidosis the build up of acid in muscle cell and no further ATP is synthesised. We now know this to be incorrect. Lactate actually helps performance during intense exercise. If a muscle cell becomes too acidic the muscle stops functioning as the enzymes that control glycolysis struggle to function in an acidic environment.

The lactate is then quickly removed from the muscle cell, protecting the cell from becoming too acidic so exercise can continue for a little longer. When this happens we are unable to sustain the intensity of exercise and have to either cease exercise or reduce the intensity. This is why even with the help of lactate we can only work at a high intensity for short periods of time. Training this system is aimed at increasing tolerance to lactate, the removal of lactate and improving the rate at which glycolysis produces ATP.

If you want the system to completely recover and clear the majority of accumulated lactate so you can repeatedly condition it you would use a ratio of 6 seconds of rest for every second of work.

Within fast glycolysis the pyruvate is converted into lactate. With lactate our body can resynthesize ATP at a much faster rate. This would occur when the activity requires a higher energy demand. Pyruvate on the left, lactate on the right. In slow glycolysis the pyruvate is shuttled to our mitochondria and we enter the citric acid cycle, or the oxidative system. In the oxidative system the resynthesis of ATP happens at a much slower rate, but we can maximize the number of ATPs produced, yielding us with the highest amount of energy.

Lactate sometimes gets an undeserving bad wrap. Many people mistakenly associate an increase in lactate with an increase in lactic acid. In fact, lactate may actually be a buffer to this metabolic acidosis. Byproducts of these reactions may be responsible for metabolic acidosis. A clearing of the lactate from the blood is therefore a return to homeostasis. This is one aspect we attempt to train during high intensity interval training.

With enough oxygen present in the mitochondria, the powerhouse of our cell, the pyruvate is converted is shuttled into the mitochondria with NADH, a byproduct of glycolysis, and then converted into acetyl CoA.

This is the start of the oxidative metabolism, which we will cover, in my next article. Glycolysis is an anaerobic metabolic pathway. The only macronutrient that can be synthesized into usable ATP under anaerobic conditions is carbohydrates. We need to make sure we take in enough carbohydrates to fuel glycolysis during activity. We also need to make sure we take in enough carbohydrates to keep our glycogen stores full. A reduction in muscle glycogen is associated with fatigue.

This is where the importance of post-workout nutrition comes into play. Studies have shown an increase in glucose uptake by muscle tissue post workout. Simple starch may be the best source of carbohydrates post workout because of their ability to raise blood sugar levels quickly.

This can allow for faster uptake by muscle cells to recover. Fruit may even be a better option. Fructose gets immediately shoveled to our liver when ingested. Upon reaching the liver it is converted into glycogen to refill liver stores it will not refill muscle stores because muscle cells do not contain a receptor for the GLUT5 transporter required to carry fructose.

Under conditions of decreased liver glycogen, such as exercise, fruit may have the ability to resupply the liver faster. The rate at which athletes can replenish ATP is limited by their aerobic capacity, or the maximum rate at which they can consume oxygen. In response, creatine phosphate CP or phosphocreatine, which is also stored in the muscle cell, breaks down into creatine C and phosphate P.

Due to the fact that CP is stored in limited amounts in the muscle cell, this system can supply energy for 8 to 10 seconds. It is the chief source of energy for extremely quick and explosive activities, such as meter dash, weightlifting, jumping, and throwing events in track and field, vaulting in gymnastics, and ski jumping.

Restoration of Phosphagen: Through restoration the body recovers and replenishes energy stores to preexercise conditions. Through its biomechanical means, the body attempts to return to physiological balance homeostasis , which it has the highest efficiency. Due to the absence of O2 during the breakdown of glycogen, a byproduct called lactic acid LA forms. When high intensity work continues for a prolonged period, large quantities of lactic acid accumulate in the muscle causing fatigue, eventually stopping physical activity.

Full restoration of glycogen takes a long time, even days, depending on the type of training and diet. For a normal, or carbohydrate rich diet, it takes 12 to 24 hours to replenish the liver glycogen.