In a scientific study conducted in England with 400 participants, a comparison was made between slow and fast breathing. The participants were divided into two groups. Both were asked to do 10 minutes of breathing exercises every day for four weeks, one group at 5.5 breaths/minute (a breathing rate used in coherent breathing), the other at 12 breaths/minute (this breathing rate represents the lower limit of breathing speed in the average population). The results showed that the subjective perception of stress and depression decreased in both groups, while the values for well-being increased. However, there were no significant differences between the slow and fast breathers.
Since the slow breathing method was named „coherent breathing“ in the study, the study would prove that coherent breathing, in which you are supposed to take between 3 and 6 breaths/minute, is just as effective as breathing more than twice as fast. There are a number of other studies and overviews that show that slow breathing improves well-being and reduces stress arousal.
So what should we think of this study? I claim that title and text of the study wrongly refer to coherent breathing. Coherent breathing not only means breathing slowly and regularly, but also relaxing the exhalation and regulating the depth of breathing in such a way that breathing is controlled primarily via the diaphragm. We know from practice that some beginners in the method find these elements of coherent breathing easy, while many struggle at first: They do not succeed in relaxing the exhalation, the inhalation takes too long, abdominal breathing is unfamiliar, the breathing rate is too slow, so that the necessary stretching of the breath creates stress, etc. There are remedies for all these initial problems, which are taught by a competent instructor. After a few practice sessions, these difficulties are overcome in almost all cases thanks to the special interventions and suggestions.
In the study, the participants were initially given information about the method, but there was no opportunity to ask questions in case of difficulties. We can therefore assume that some of the participants of the study had problems with relaxing the breathing and were therefore unable to gain better recovery results. As simple as the method of coherent breathing appears, because only three or four basic elements need to be considered, there are many pitfalls in practice. Everyone has their own breathing habits that have been ingrained over years and decades. It therefore takes time, motivation and consistent practice to change them in a favourable direction. The discussion of the study results in the publication also addresses this fact and cites studies in which coherent breathing was practised under individual guidance, with clearly positive effects. While the study criticized the insufficiently "robust" design of these experiments, these studies also provide important findings.
A further point of criticism of the study that I (like the authors of the study) have is the fact that the average number of practice sessions was 20, i.e. that it is not possible to speak of a consistent practice discipline, which is particularly important at the beginning in order to make lasting changes of firmly established breathing habits. In addition, no one knows whether the method was practiced correctly at all or only somehow.
The participants were also not informed as to why they should take 5.5 breaths/minute. With coherent breathing in particular, it is important for many beginners to understand why they should breathe in this way and not in a different way so that they can motivate themselves to practise coherent breathing. For some people, motivation comes from experience: they like an exercise because they feel the positive effects. For others, it comes from mental understanding: they recognize that the exercise could be valuable from a theoretical point of view and then practice it. There are always beginners who refuse to adhere to a strict guideline such as that required for coherent breathing. Only when they understand the reason they are prepared to train with it. Such resistance, which we know from teaching coherent breathing, was not taken into account in the study. So consequently, the authors of the study also assume that appropriate "psychoeducation" would have led to better results with coherent breathing.
Furthermore, the study authors point out that there is a study that shows that a breathing rate of 8 breaths/minute produces better results for vagal activation, i.e. for stimulating the parasympathetic nervous system, than 12 breaths/minute, which in turn performs better than 16 breaths/minute. It therefore proves that the slower you breathe, the greater the effect on relaxation and on lowering blood pressure. In the study discussed here, the positive results for the "placebo" group, who breathed at 12 breaths/minute, can be attributed to the fact that many were able to experience a reduction in their otherwise even higher usual breathing rate as relaxing and mood-enhancing. Both study groups obviously benefited from the breathing awareness, regularity and deepening of breathing. Both groups were also instructed to breathe through the nose, which has multiple health effects, including improving oxygen uptake and regulating anxiety and stress management in the brain.
The next point of criticism relates to the lack of physiological evaluations of the breathing exercises. The study results come from questionnaires completed by the participants. They are therefore subjective mood reports, and there is no data on heart rate, heart rate variability, blood pressure or sleep quality. It is often impressive for beginners in this method to see in real time, how their breathing pattern and their heartbeat synchronize, and those who like to go deeper can measure their heart rate variability and its improvement over the time of practice. In this study, it could well be that the physiological status of those who practiced coherent breathing was improved without being noticed.
To summarize: The study discussed raises more question marks than it answers - and these are suggestions for more and more detailed research. Anyone working in this field can derive from this study the many benefits of working with conscious breathing.
Further reading:
Coherent Breathing
