When we spend time outdoors, it not only helps us relax and lifts our spirits – the positive effect can even be seen in the brain, as a small pilot study now suggests. In this study, brain scans using magnetic resonance imaging showed that the gray matter in one area of the frontal lobe benefits from being outdoors. Next, the scientists want to investigate whether a walk in the countryside works better than a walk through the city.
Whether in a city park, garden or forest: When we are in nature, it is good for body and soul, as several studies have shown in recent years. The stay in the country relaxes us, makes our heart beat slower and lifts the mood. People who live in greener urban districts suffer less from cardiovascular diseases, diabetes and other lifestyle diseases, and children’s ability to concentrate increases. But excursions into the countryside also have a positive effect: in 2019, a study found that just 120 minutes in nature per week are enough to promote health.
Significant effect on the frontal lobe
Simone Kühn from the Max Planck Institute for Human Development in Berlin and her colleagues have now investigated the effect of being outdoors on the brain. To do this, they regularly examined the brains of six healthy adults living in Berlin over six months using magnetic resonance imaging (MRI) – they performed a total of 280 such brain scans. In addition, they recorded how much time the participants had spent outdoors in the 24 hours prior to the examinations, and asked about other factors that might affect the brain. This included how much fluids and how many caffeinated drinks the test subjects had consumed, how much free time they had and how much exercise they had done.
The studies showed that staying outdoors not only raised the mood of the test subjects, but also had immediate effects on the brain. The more time the participants spent outside before the examination, the greater the volume of gray matter in the right dorsolateral prefrontal cortex. This was an area of the cerebral cortex lying to the side behind the forehead, which is involved in the planning and regulation of actions and in what is known as cognitive control. Many psychiatric disorders are linked to reductions in gray matter in the prefrontal area of the brain.
Effect independent of other influencing factors
Even for the research team, it was surprising that this positive effect of being outside persisted even if all other influencing factors such as the duration of sunshine, leisure time, physical activities and fluid intake were factored out. “It was a real surprise for us that none of these covariates could explain the differences in the right dorsolateral prefrontal cortex,” said Kühn and her colleagues. The study thus proves that time outdoors has a positive effect on the brain regardless of other influencing factors. This apparently even applies regardless of whether we are in the city or in the countryside, and even for very short periods outdoors.
“Our results show that our brain structure and mood improve when we spend time outdoors,” says Kühn. “It can be assumed that this also has an effect on concentration, working memory and the psyche as a whole.” This agrees well with the results of meta-analyzes, which also show positive effects of a stay in nature on the psyche. If you are regularly in the fresh air, you are not only doing something good for your well-being, but also for your brain. In a further study, the research team would like to determine whether a stay in the country might even increase these positive effects. To do this, they equip their test subjects with GPS loggers and sensors, which they can use to record factors such as light exposure, pollutants and noise.
Source: Max Planck Society; Technical article: The World Journal of Biological Psychiatry, doi: 10.1080 / 15622975.2021.1938670