The best medicine for sadness, anxiety, obesity and alterations in the microbiota? The simplest thing there is, moderate and regular physical activity! Small changes to your habits every day are enough to obtain a great benefit in terms of physical and mental health, as shown by two very recent scientific studies, the first published by a Spanish team in the journal Nutrients (Aragon Vela et al, Nutrients, 2021), the second appeared in the journal Frontiers in Psychiatry thanks to a collaboration between American and Irish scientists (Meyer et al, Frontiers in Psychiatry, 2021).
The link between physical activity, microbiota and overweight
Spanish research has focused attention on the fascinating link between physical activity, microbiota and obesity. What emerges is that a high body mass index, accumulations of visceral fat, resistance to insulin and an increase in the release of inflammatory substances are associated with a poor diversity of bacteria in the intestinal microbiota. Instead, regular physical activity, in addition to improving energy expenditure, makes the population of the microbiota more diverse and increases the presence of beneficial bacteria capable of producing short-chain fatty acids. These substances are involved in several processes, including the modulation of the immune response. Not only that, short-chain fatty acids regulate appetite and insulin sensitivity and are capable of promoting greater, and better, use of energy by the muscles as well as stimulating the burning of fats. So, from here we understand how physical exercise can beneficially influence the intestinal microbiota, maintaining its diversity or, if this has been altered by an overweight condition, restoring it, and hence is able to help prevent or fight obesity.
Physical activity and mental health
But moderate physical activity also improves mood, counteracting depression and sadness. The second study focused on understanding the association between physical exercise and mental health. During the first phase of the pandemic, we had to radically change our habits. Life suddenly became sedentary. Unfortunately, in many cases, it still is. In fact, since many meetings, jobs or even lessons take place online, we have lost the part related to travel, which we might have previously been able to do on foot. In some cases, we have also abandoned the habit of going for a walk, preferring instead the sofa and a new TV date. All of this has led to an increase in anxiety and depression. The researchers recruited more than 3,000 volunteers who were asked to fill out, once a week from March 2020 until the end of the experiment, in June 2020, a questionnaire indicating lifestyle and mental condition. Well, what emerged is that the feeling of experiencing stress and sadness has passed or has diminished in those who, after the first periods of sedentary lifestyle, then resumed an active life, while it was always present in those who decided to continue with sedentary life. Not only that, it has also been observed that anxiety and depression are ready to return if you switch back from a life that includes moderate physical activity to a sedentary life. So, the study author's suggestion is to try to make small lifestyle changes. For example, if we used to take the time to get to work, go to a meeting or go to the gym, now instead of using this time sitting down we can take a short walk.