How should your breathing be while you exercise?

When we go for a run or we lift weights in the gym, we often worry about what clothes and shoes to wear, how to warm up the muscles or even how many heartbeats to achieve for the training to be effective. However, we tend to ignore the effect of the breathing on physical performance.

Science has a lot to say about how to get more out of our gym hours by paying attention to how we breathe.

Oxygenation mechanism during exercise physical

We are all aware that the mission of the respiratory system is gas exchange. That is to say, it is in charge both of obtaining oxygen (O2) from the outside to produce energy and of eliminating the waste product, carbon dioxide (CO2). Therefore, it allows us to live.


But let’s break down the process more technically. Air enters through the nose, circulating through the airways to the pulmonary alveoli, where gas exchange takes place. From there, oxygen passes into the blood to be transported to all cells. At the same time, the CO2 they produce is transported to the lungs for elimination.

This is how it works under normal conditions, but what happens when we do exercise? Well, the muscles work much more intensely, consuming more oxygen and producing more CO2. The frequency goes from 15 breaths per minute at rest to 40-60 per minute in full activity. As a consequence, the amount of air that enters increases, which goes from 12 to 100 liters.

During this extra exchange of gases, our respiratory system is responsible for keeping the acidity of the blood constant, which is measured by pH, by expelling CO2.

Another detail to take into account is that oxygen reaches the muscles through the blood thanks to the red blood cells (the “carriers” that carry it from the lungs), specifically through a macromolecule called hemoglobin. Well then, for an oxygen molecule to be captured by the hemoglobin in the red blood cells that pass through the lung, another CO2 molecule is needed that allows the hemoglobin to release oxygen at the destination. Ultimately, it is the amount of CO2 in the body that determines the correct supply of O2 to the muscles.

If we breathe through our mouth we run out of breath

Now that we know about hemoglobin, we cannot forget about a key property: the Bohr effect. It refers to the fact that when we activate our body, there is an increase in CO2 and, therefore, in hydrogen ions, causing the pH to become acidic. This makes hemoglobin capture oxygen with greater affinity, achieving a greater contribution of O2 in those areas of our body where more CO2 is released.

How should your breathing be while you exercise?


Therefore, doing exercise, our body generates more CO2, and the Bohr effect kicks in. In short, the Bohr effect allows our friend hemoglobin to release more oxygen the higher our activity.

Therefore, in matters of breathing We should not just be guided by intuition. Although one might think that to do exercise physical it is better to breathe through the mouth, if we expel the air through the mouth we run the risk of losing too much CO2. In fact, when we get out of breath doing exerciseit is not because our muscles get tired, but because they are not receiving oxygen well because they do not have enough CO2 for exchange.

After reviewing the scientific works of recent years, a recent publication concluded that it is not so clear that it is good to use the mouth to breathe during sport. Furthermore, the evidence suggests that the breathing exclusively nasal is feasible for most people at moderate levels of exercise aerobic without a specific adaptation, and that this approach of breathing can also be achieved during intense levels of exercise aerobic.

airways open more

Another reason to breathe through the nose is nitric oxide (NO), a vasodilator that is produced in the epithelial cells of the nasal cavity as air passes through. It is known that nitric oxide, among other functions, participates in chronic inflammation processes and in the modulation of lung function. And it is also a powerful vasodilator that diffuses very quickly, achieving a greater opening of the respiratory tract.

This is very important for people who suffer from asthma induced by exercise. In fact, it has been shown that this pathology is greatly improved by breathing through the nose.

How should your breathing be while you exercise?


Schematic of the action of nitric oxide (NO) on the nasal epithelium and muscle cells. (FRONT PHYSIOL. 2021)

With maximum effort, the mouth opens

We have explained that the breathing helps athletes to obtain better performance, especially when the effort is sustained and moderate. Although breathing through the nose takes less air into the lungs, the air supply is sufficient to maintain activity and does not seem to cause problems.

However, things change when more demanding conditions are reached. With maximum effort, athletes change their breathing to the mouth automatically. Interestingly, scientists have shown that this change occurs earlier in women than in men by increasing the intensity of the exercise. exerciseand they explain it because women tend to have smaller noses.

In the most demanding and fastest race, the 100-meter dash, athletes breathe through their nose and mouth simultaneously. Of course, in just 10 seconds. It is enough to observe Carl Lewis or Usain Bolt in the Olympic finals to verify it.

The exception of yoga and pilates

There are two exceptions to the cases we have previously considered: yoga and Pilates. In these two modes of exercise physical, the breathing It is a very important part, and its technique is the first thing you learn. This is always of the nose-mouth type (that is, it is inhaled through the nose and exhaled through the mouth). This is especially important in the case of Pilates, with a very determined execution that involves (and shapes) the muscles that surround the rib cage, exercising them both when breathing in and out.

How should your breathing be while you exercise?



Using a technique called EMG or “electromyography” to measure muscle activation in real time, the beneficial effects of breathing pilates. Specifically, in elderly people there are studies that show the great benefit of breathing Pilates to encourage muscle activation by doing exercise. And the benefits go further: spinal alignment is also improved and loss of balance is avoided.

There is, therefore, no single answer to the question about how we should breathe during the exercise physical: depends on the type of activity. What we are convinced of is that the next time you listen to the explanations of your instructor or coach on how to breathe, you will not think: “what a heaviness” or “what else does it matter”. Because a good routine breathing It will influence your performance.

It may interest you

Learn to breathe and reduce anxiety (in 3 steps)