The role of sport as a protective factor for physical health is well known and supported by numerous scientific literature. In the recent years, more and more studies have clarified and shown the protective role of physical activity and mental health. So far, studies on the relationship between sport and mental health have paid more attention to depression, showing that physical exercise produces changes in the body and brain, with a strong antidepressant effect.
Depression is a chronic condition with a prevalence of up to 20% throughout life and is a major source of disability. The standard treatment recommended in clinical guidelines includes pharmacotherapy and psychotherapy. Physical activity and sport are indicated in these guidelines for their beneficial effects in the treatment of depression. Several recent studies have analyzed the effect of sport on depressive symptoms, presenting firm conclusions about its effectiveness.
In a theoretical synthesis, published on December 2016 in the Preventive Medicine journal, was concluded that it exists a strong link between physical activity and mental health. More specifically, lack of physical activity predisposes to a high risk of developing depression, while moderate physical activity is a major protective factor for prevention of depression.
Researchers, coordinated by Felipe Schuch of Centro Universitario La Salle, Brazil, used the meta-analysis method to summarize the results of three longitudinal studies that investigated the association between cardiovascular resistance and depression (cardiovascular resistance refers to system capacity circulatory and respiratory system to provide energy support during exercise).
Researchers started from the hypothesis that low cardiovascular resistance is associated with a high risk of depression. Two of the three studies were conducted in America and one in Sweden and included a total of 1,142,669 people, of whom almost 98% were men (1,128,487 men and 3040 women).
Cardiovascular resistance was measured by objective methods – treadmill exercises, pedaling on a stationary bicycle and climbing stairs. The mental health of the participants was measured by standard tests at the beginning and end of the studies. Participants were observed up to 40 years after the end of the study.
It turned out that women and men with low and medium levels of cardiovascular resistance were at high risk of developing depression. In particular, those with the lowest and median cardiovascular resistance levels were 75% and 23% more likely to develop depression than those with the highest cardiovascular resistance. It has been found that high cardiovascular resistance is a significant protective factor against depression both for women and men. Cardiovascular resistance can be enhanced by sports.
The researchers’ conclusion was that interventions aimed at improving cardiovascular resistance through sports provide significant antidepressant benefits. These are backed up by data from previous studies showing that any level of physical activity, including low levels such as light exercises or a walk, can prevent depression.
In a separate study, published in June 2016 in the Journal of Psychiatric Research, the same researcher, Felipe Schuch, along with his colleagues investigated whether physical exercise could be useful as a treatment for depression already installed. They synthesized the results of 25 studies, including 1487 people, where people with symptoms of depression above the clinical threshold or with a diagnosis of major depressive disorder who followed an exercise program were compared with people with symptoms depressed over the clinical threshold, or with a diagnosis of major depressive disorder that did not exercise.
Generally speaking, physical exercise has a significant and high antidepressant effect for people with depression. In particular, moderate and high intensity aerobic exercises supervised by a qualified instructor have significantly improved depressive symptoms, with better outcomes for people with more severe symptoms. The authors conclude that previous studies may have underestimated the benefits of physical exercise for people with depression and argue that the data from this analysis provides robust evidence of the effectiveness of exercise for depression management.
It is clearly established that sport produces changes in body functioning and shape. Mechanisms through which physical activity alters our mental state and emotions are less understood. In February 2016, Felipe Schuch and his colleagues have publications study in Neuroscience and Biobehavioral Reviews, in which they investigated neurobiological responses after exercise in people with major depressive disorder. In other words, they were interested in finding out what changes in the body and brain during sports, and how these changes could lead to an improvement in mental status. Researchers have synthesized data from 20 studies, including 1353 people diagnosed with major depressive disorder.
Blood samples were analyzed before and after doing sports. Researchers argue that the etiology of major depressive disorder is unknown and multifactorial. They point out that exercise induces acute responses (transient effects occurring immediately after a round of exercises) and chronic responses (changes that occur after a longer period of training), both having effects on the endocrine system, neurogenesis, inflammation, oxidative stress, and cortical activity. It is believed that complex interactions between these systems could provide an explanatory response to the antidepressant effect of sport, but they are not fully understood. The study found that sport significantly reduced certain markers of inflammation and increased levels of hormones and biochemicals that are believed to contribute to brain health. However, more studies are needed to reach a firm explanation.
Generally speaking, physical exercise is considered a valid intervention, with significant and undeniable beneficial effects for the management of depression symptoms. The main message of the researchers is that people need to be active to improve their mental health.