Breathing usually happens without us having to think about it. At the same time, various health gurus want to teach us how to breathe better. Are they onto something?
Text: Fredrik Hedlund, first published in Medicinsk Vetenskap, nr 2 2026
We do it more than 20,000 times a day without even thinking about it. Breathing is the body's most fundamental rhythm, at around 15 breaths per minute at rest. But as soon as we start moving or become emotionally affected, the pattern changes immediately.
Most people believe that we breathe primarily to take in oxygen for the blood. It is true that our cells need oxygen to survive, but even more important is to get rid of carbon dioxide.
"When we hold our breath, it is not the lack of oxygen that first causes discomfort, but the rising level of carbon dioxide in the blood," says Peter Lindholm , senior consultant and researcher at the Department of Physiology and Pharmacology at Karolinska Institutet.
He has recently returned from the United States, where he worked as a professor of hyperbaric and diving medicine at the University of California.
Faster breathing during stress
When the body is exposed to stress, an evolutionarily inherited response is triggered, preparing the body to perform work that was originally about survival.
"Whether you have to run away from someone trying to eat you, or if you are trying to catch someone you want to eat, the body prepares itself by increasing the breathing rate. As the breathing rate speeds up, so does the heart rate. The chest acts like a bellows, helping to draw more blood into the heart. At the same time, more carbon dioxide is breathed out. Carbon dioxide acts as an acid in the blood, so when more carbon dioxide is exhaled, the blood becomes more alkaline. This enables the body to better handle the lactic acid produced in the muscles when you run at maximum intensity," he says.
In other words, you can run faster and for longer by exhaling carbon dioxide before the muscle work begins. These days, we rarely need to run for our lives in that way, but the link between stress activation and breathing is there whether we like it or not.
Slow breathing calms the body
Just as increased stress raises the breathing rate, slowing the breathing rate can lower stress. This is used both in relaxation exercises and in psychological treatment. By consciously taking calm breaths, the physiological stress response can be broken. A well-known example is the so-called 'box/square breathing', a technique for managing stress in which the person visualises a square and breathes in, holds, breathes out and holds again at even intervals.
"It has a dual effect. On the one hand, you trick the brain into focusing on the square instead of whatever is causing the stress. On the other hand, you make use of physiology. If you breathe more calmly, your heart rate drops, which signals to the brain that the danger is no longer so serious," says Peter Lindholm.
In box/square breathing, the duration of inhalation and exhalation is often the same, but in many other relaxation exercises, the emphasis is on making the exhalation longer than the inhalation. This, too, has a physiological explanation, Peter Lindholm explains.
"Inhalation is an active process, involving muscles that expand the chest. More blood is drawn into the heart, which makes the heart rate increase slightly. The pulse rises by two or three beats when you inhale, then drops by two or three beats when you exhale. The exhaled phase is the relaxed one. If you simply relax and sigh or hold your breath, you are in that resting state," he says.
Hyperventilation can lead to fainting
The positive effect that can be achieved by exhaling carbon dioxide at a slightly higher breathing rate before a maximum effort can quickly turn into the opposite, if the forced breathing is overdone. This is known as hyperventilation. If done too much and for too long, an imbalance develops where too much carbon dioxide is expelled, making the blood overly alkaline. This disrupts the body's calcium balance and makes the nerves more excitable. At first, this is felt as dizziness and tingling in the fingers and lips, but it can have far more serious consequences.
"There are even people who can faint from hyperventilating," says Peter Lindholm.
He explains that this is a particular problem in his field of diving medicine.
"If you hyperventilate before a dive, you can suppress the breathing reflex so that you can hold your breath until you pass out. Every year, a few people drown because of this. They come up with this technique themselves; they stand and breathe heavily before diving, and then they lose consciousness underwater and drown," he says.
The technique has also become popular among various health gurus. One well-known figure is the Dutch extreme athlete Wim Hof, who advocates both a form of hyperventilation and challenging physical exercises such as ice baths, though not at the same time. However, the breathing exercises are not without risk and can be directly life-threatening if combined with ice swimming or water in general, which has happened and resulted in a number of deaths over the years.
Other variants include so-called 'holotropic breathing', which is said to lead to altered states of consciousness and facilitate the exploration of inner experiences, and 'breath of fire', an invigorating breathing technique used in some forms of yoga.
Altered breathing patterns in post-COVID
There are, however, conditions in which breathing does not function as automatically and effortlessly as it does for most of us. This is known as dysfunctional breathing, a condition researched by Malin Nygren-Bonnier . She is a physiotherapist and associate professor at the Department of Neurobiology, Care Sciences and Society at Karolinska Institutet, and leads a research group that, among other things, studies dysfunctional breathing in post-COVID patients.
"This means that you have an altered breathing pattern that does not meet the body's needs. It may involve irregular breathing or breathing very high up in the chest, so that you do not achieve optimal ventilation. This is quite common among patients with post-COVID, for example," she says.
The solution is to actively practice breathing in a functional way again.
"The treatment is called 'breathing retraining', where patients learn to breathe properly using their diaphragm and establish a regular breathing pattern," she says.
CBT is being tested for asthma-related anxiety
People with asthma pay a little extra attention to their breathing. Asthma is a condition in which the airways can constrict, making it difficult to breathe. However, with well-adjusted medication, this is rarely a problem. Nevertheless, three in ten people with asthma experience heightened anxiety and worry, which may be linked to their breathing or the fear of an asthma attack. That is understandable, as an asthma attack is unpleasant and, in the worst case, can have severe consequences. But when it leads to the person restricting their life, the worry is no longer helpful.
"It might mean not daring to push yourself when exercising or not daring to exercise at all. Or completely avoiding going out when it is cold outside, for example. Then the anxiety becomes disproportionate and limits the individual's life," says Marianne Bonnert , psychologist and researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
She has developed an internet-based CBT treatment that can reduce anxiety and improve quality of life and asthma control in adult patients with asthma-related anxiety. She is now leading a similar study in children aged 8 to 17, which will investigate whether it is possible to prevent children from developing long-term restrictions in everyday life at an early stage. The results are not yet final, but based on what has been evaluated so far, they look promising, according to Marianne Bonnert.
"Most seem to be satisfied with the treatment," she says.
Tip! Three breathing exercises with a calming effect
Cyclical breathing. Take a normal breath in through your nose. Then inhale additional air through your nose, as much as you can. Then breathe out very slowly through your mouth until all the air is released again.
Box/square breathing. Breathe in through your nose for four seconds, hold your breath for four seconds, breathe out for four seconds, hold your breath for four seconds.
- Alternate nostril breathing. Close the right nostril with a finger. Breathe in and out slowly through your left nostril. Switch nostrils and repeat. Finish by exhaling through your left nostril. Start again by breathing in through your left nostril.
Exercises 1 and 2, along with one additional breathing exercise, were compared in a study with mindfulness meditation, where attention is paid to the breath without altering it. Both exercises had a greater effect than mindfulness meditation on levels of anxiety and negative emotions. Cyclical breathing had the greatest effect. Try it and see whether it works for you.
Sources: Balban et al., Cell Reports Medicine, January 2023; Marian Papp
