Recap: Aerobic and anaerobic exercise

As you learn how to train, you should know the characteristics of aerobic and anaerobic exercise. Do you know how to tell them apart?

When you exercise, cells transfer chemical energy from a fuel source such as glucose to adenosine triphosphate molecules, carrying out a basic metabolic process called cellular respiration.

There are two categories of cellular respiration related to aerobic and anaerobic exercise. Aerobic respiration requires oxygen, while anaerobic respiration does not, but both are energy-producing biochemical processes that serve different functions:

• On the one hand, anaerobic respiration provides energy quickly when it is needed on short notice and for short periods of time.
• On the other hand, aerobic respiration provides energy steadily as a constant energy source.

Characteristics of cellular respiration

Both aerobic and anaerobic respiration are types of cellular respiration. The ATP produced as a result of this biochemical process is used by the cell to obtain energy when needed; energy is released when ATP loses a phosphate group to become adenosine diphosphate.

It is clear that both types of cellular respiration used for aerobic and anaerobic exercise use glycolysis to produce ATP and generate energy by breaking down glucose.

Likewise, they produce by-products and depend on chemical reactions located in the cytosol, using pyruvate as a substrate.

Of course, both processes depend on enzymes to catalyze their respective chemical reactions.

Aerobic respiration

Glucose and oxygen interact to release energy, with carbon dioxide and water as by-products.

It is so efficient that it can produce 38 ATP molecules per glucose molecule.

The chemical stages of aerobic respiration occur in:

• The cytosol: glycolysis.
• The mitochondria: the Krebs cycle, in which pyruvate serves as a substrate in the pathway, and electron transport.

Therefore, aerobic respiration provides energy for prolonged, less intense workouts, when your body can absorb and deliver enough oxygen to the cells to support this more efficient way of generating ATP.

Anaerobic respiration

When comparing aerobic and anaerobic exercise, you should also know what happens in the absence of oxygen.

Glycolysis takes place during anaerobic respiration, just as it does during aerobic respiration. However, the subsequent stages are different because no ATP is generated beyond the two molecules produced during glycolysis.

A by-product of anaerobic respiration, lactic acid, contributes to fatigue and muscle discomfort. That is why, when you pant or “catch your breath” after exercising, your body is trying to take in enough oxygen to restore a chemical state capable of clearing unwanted by-products, such as lactic acid, which accumulate when oxygen is scarce.

Aerobic and anaerobic exercise: what are the differences?

Aerobic exercise produces energy using a continuous oxygen supply to maintain your current level of activity without needing additional energy from another source.

In contrast, anaerobic exercise causes your body to demand more energy than your aerobic system can produce. To produce more energy, it uses an anaerobic system based on the energy sources stored in your muscles.

In other words, anaerobic exercise breaks down glucose into energy without using oxygen and is generally short in duration and high in intensity, releasing a great deal of energy in a short period of time when your oxygen demand exceeds your oxygen supply.

Fast-paced workouts such as sprints, high-intensity interval training (HIIT), and jumping rope are the most intense forms of anaerobic exercise.

Exercises and movements that require brief bursts of intense energy are also examples of anaerobic exercise, such as weightlifting, sprinting, and so on.

The science behind anaerobic exercise

Your body needs oxygen to use fat as fuel, and because aerobic exercise uses oxygen to produce energy, it can use both fat and glucose as fuel.

To contrast aerobic and anaerobic exercise, you should know that the latter can only use glucose as fuel.

• Glucose is available in the muscles for fast, short movements and can be used when the aerobic system is working at maximum capacity for a short period of time.
• When you begin exercising vigorously, there is a temporary shortage of oxygen reaching your working muscles, which means anaerobic exercise must be fueled by glucose through a process called glycolysis.

Glycolysis occurs in muscle cells during high-intensity training without oxygen, producing energy quickly.

This process also produces lactic acid, which is why your muscles become so tired after the burst of energy.

However, if you perform anaerobic exercise regularly, your body will be able to tolerate and eliminate lactic acid more efficiently, meaning you will tire less quickly.

Benefits of anaerobic exercise

Anaerobic exercise is associated with the hard work you have to do at the gym, but its benefits are enough to encourage you to focus on it, even if you are following a fat-burning or definition plan.

• Increases strength and bone density
• Promotes weight maintenance.
• Helps manage lactic acid more effectively.
• Elevates mood and can even alleviate depression.

Without a doubt, it can help you in different ways:

Anaerobic exercise helps stimulate metabolism: as you develop and maintain muscle mass. The more lean muscle you have, the more calories you will burn during your next session; it also increases calorie burning at rest after training.

Anaerobic exercise increases your lactate threshold: by training regularly above your anaerobic threshold, your body can increase its ability to manage lactic acid, thereby raising your lactate threshold. In other words, the point at which you experience fatigue, meaning you will be able to exercise harder for longer.

Anaerobic exercise reduces the risk of disease: increases in strength and bone density obtained through high-intensity anaerobic training, such as squats and bodyweight push-ups, help reduce the risk of diabetes and heart disease.