Downward-Facing Dog, Warrior, and Dancer are believed to relieve depression, anxiety, and pain. Yoga can also be used to train memory. As? Brain research has clues.
Yoga is more than a trend, yoga is a movement. Imported from India, the practice has become a popular sport in the West. In Germany, more than 15 million people now do the sun salutation, stretch their legs in the downward facing dog or sit meditatively side by side in the lotus position to relax, manage stress, strengthen their backs and stay fit. Or are at least interested in embarking on the gentle path to well-being. Most practitioners expect an improvement in their physical well-being and psyche. And that’s not a felt truth.
Doctors and psychotherapists have been exploring the healing effects of yoga for decades. As early as 1956 , the neurologist Mariella Fischer-Williams reported on a patient who, by practicing yoga, relieved his chronic pain – and was ultimately even said to be completely pain-free. Now, a single case alone says nothing. In 1975, however, a comprehensive investigation followed in the journal The Lancet . The team of authors showed that yoga reduced high blood pressure more than mere relaxation. Even memory is trained through yoga . And the exercises should also help with depression, anxiety and chronic pain.
But why is that? To find out, scientists are increasingly focusing on the brain. They push subjects into the tube of a magnetic resonance tomograph (MRT), measure brain regions and investigate how yoga changes electrical tension in the thinking and control organ. This should bring results that are as objective as possible. For a good reason: scientifically investigating yoga is quite problematic.
Yoga can be sporty or extremely calm
“There’s the question of definition,” reports Holger Cramer, head of research at the clinic for naturopathy at the Evangelische Kliniken Essen-Mitte. Traditionally, yoga involves a combination of intense stretching exercises and postures called asanas, as well as various techniques of relaxation and meditation called samyama. The breath, the pranayama, is also very important. In yoga, it is considered the link between body and mind and is said to help remove the “veil that covers inner enlightenment,” as it says in the Yogasutra, a kind of manifesto of yoga.
Over time, however, different styles have emerged, each with its own focus: Hatha and Iyengar Yoga consist mainly of stretches and relaxing poses, Ashtanga and Vinyasa are usually more dynamic, contain more sporting elements and are even accompanied by techno in some places -beats instead. Next to it is the Bikram: This includes 26 postures that are repeated twice in a 38-degree room. Sweating is inevitable. In contrast, in Yin Yoga you hardly move. This is all about slow stretching and meditation.
“So what exactly ‘yoga’ is is difficult to say,” says Cramer. When study participants report that they feel better after class, the question also arises: what actually? Was it the physical exercises, the concentration on the breath? Is it perhaps the feeling of being part of a larger group, or was it the teacher’s particular style? All factors, so-called confounders, that complicate yoga research.
The best introduction to yoga
First of all: “Put your perfectionism aside and free yourself from any claim that you have to do the exercises perfectly,” advises the psychologist Ulrich Ott. Yoga is not about performance, but about developing awareness of one’s body, emotions and mind. The positions unfold their full effect when they are performed with conscious breathing and full attention. “Only go so far that you can still breathe easily,” emphasizes the yoga expert. If you hold your breath or breathe very hard, it is a sign that you are overexerting yourself. It is also important to warm up before the individual exercises – which happens, among other things, with the sun salutation.
Care should be taken with advanced poses such as headstands or strong backward bends. “If you don’t do it correctly, you can easily injure yourself,” warns Ott. The safest way to start is therefore to take part in a course under qualified guidance in a very conventional way. Many such offers are even subsidized by the statutory health insurance companies (GKV). The website of the National Association of Statutory Health Insurance Funds provides an overview of these courses.
So now let’s take a look inside. So much can be said right from the start: “It doesn’t matter whether it’s traditional hatha, vinyasa with techno beats or sweaty bikram – they all change our brain,” says Ulrich Ott, psychologist at the Bender Institute of Neuroimaging at Justus Liebig University in Giessen : “Because the various body positions, breathing exercises and meditations are normally practiced repeatedly over a longer period of time.” And our mind generally reacts to repeated practice with functional and structural adjustments. That is, the brain regions that are used differentiate and the synaptic connections become stronger. It is comparable to a muscle that gains strength through regular training.
“However, this finding is not sensational,” neuroscientist Ott points out: “Every hobby that a person pursues over a long period of time changes the brain: reading as well as cycling.” to take a closer look.
The gray matter lasts longer
Two papers from 2019 provide a good overview of the current state of neuroscientific research . In order to avoid the difficult question of definition, they are based on the three basic elements of all yoga styles: the physical postures of the asanas, meditation and breathing exercises. Each of the three components affects the brain differently. The teams measured the changes mostly with structural MRI images. Many studies include a series of cognitive and motor tests.
For example, yoga has a strong effect on the volume of the gray matter. The substantia grisea is composed primarily of nerve cell bodies. It is an essential part of the central nervous system and decreases over the course of life in humans. Less gray matter affects memory and could increase the risk of dementia , among other things . Yoga seems to slow down this age-related decline, if not to ensure the formation of new nerve cell bodies.
The yoga practitioners also performed better in memory and attention training as well as motor exercises. The study authors explain that this is probably because the altered brain areas are primarily responsible for cognitive control, the coordination of movements and the evaluation of decisions. For example, beta waves, which are associated with cognitive performance, are particularly active after breath-based yoga .
In another experiment , researchers from the US subjected people who practiced yoga and others to the Stroop test: they were shown pictures with differently colored words and the subjects had to name the colors of the words presented. Errors in the experiment usually arise with color words that do not correspond to their printing color. So if the word should be read out in blue even though it was printed in green. The result: Those who did yoga not only did better in the test, the MRI also showed that the dorsolateral prefrontal cortex (DLPFC) was particularly active during the experiment, while the amygdala – also known as the amygdala – was hardly active.
In addition, yoga can help to better perceive and regulate feelings, the study authors write. What supports the thesis: Yoga practitioners show a higher frequency of alpha waves after meditation, breathing exercises and asanas. These brain waves are relatively slow and put the brain in a resting state in which it vibrates more slowly and can therefore absorb more.
And that’s not all. In one part of the forebrain, the ventral striatum, the neurotransmitter dopamine rises sharply during meditation exercises. This has been shown by neurophysiological studies on very experienced male yoga practitioners . Dopamine is an endogenous mood enhancer and stimulates important cognitive processes in the prefrontal cortex. When dopamine levels drop, attention, focus, and other mental abilities usually decrease. Many studies also report a decrease in the stress response. Accordingly, an eight-week hatha yoga program lowers the blood level of the stress hormone cortisol significantly more than stretching. The yoga practitioners also learned faster and performed better on accuracy tests. However, the researchers have not yet been able to find out how this works in detail.
First neurological changes after just 20 minutes?
So there is a lot of evidence that yoga changes our brains. But are the changes sustainable? Is going to the gym once a week enough, or does it take years of training? “So far we can’t say that definitively,” says medical scientist Cramer. The research situation is not clear on dose and duration, even if there are many indications that even short-term practice has an effect.
The first neurological changes could already be observed after a meditation session of only 20 minutes . In another study, however, it took six to eleven hours. In turn, perseverance is probably required for demonstrably more substantia grisea: people who have been practicing yoga intensively regularly for several years or decades sometimes have a larger volume of gray matter than those who have only been doing yoga for a short time . However, the cause-effect relationship is difficult in such studies: “It would also be possible that the long-term yogis had a larger brain volume even before practicing,” Cramer points out.
Is yoga safe?
Almost 80 case reports are known in the medical literature about so-called “adverse events” related to yoga. These range from muscle strains and injuries to torn ligaments and fractures to a worrying increase in eye pressure. “Indications of such risks are important,” says health scientist Holger Cramer. However, such individual cases cannot be generalized.
In fact, injuries are probably not significantly more common in yoga than in other sports. This is shown by a comprehensive meta-analysis from 2015 that Cramer contributed to. Only two percent of the study participants reported undesirable side effects of yoga practice; these also usually passed quickly.
But be careful: People with previous illnesses should definitely talk to the yoga teacher and, if necessary, to their doctor in advance.
“Lifestyle could also play a role,” says neuroscientist Ott. For example, surveys show that people who do yoga are more physically active than the general population, tend to eat healthier, are less likely to be overweight, and are often well educated — “all factors that positively impact brain structure and function ‘ explains Ott. “Moreover, many studies simply compare yoga practitioners with those who do not do yoga,” adds psychologist Cramer.
Such investigations are important in ascertaining the absolute effects of yoga. Additional studies with control groups that do another type of sport and a comparison between the individual styles would also be important. Because even if Hatha, Bikram and Vinyasa are similar in the basic elements, they are different in their characteristics. Not to forget the usually small number of test subjects. On average there are between 25 and 36 people – when it comes to 100, but sometimes only four. “It’s not representative,” says Ott. In order to differentiate the mechanisms of action more precisely, you need data on lifestyle and long-term studies in addition to the MRI images.
For many researchers, however, there is no question that yoga changes our brain and has a positive effect on body and mind. These are effects that, with a bit of luck, can also be used therapeutically. A team at the Charité is currently investigating how well anxiety can be treated with yoga. Yoga can also be useful to prevent dementia and to treat stroke patients and people with Parkinson’s disease. “However, what exactly the training for these groups should look like has to be investigated first,” says neuroscientist Ott. Practicing yoga may relax; researching it is still a lot of work.