An international team of scientists, led by specialists from the University of Castilla-La Mancha and the Karolinska Institutet, conducted the largest analysis to date, demonstrating a direct link between physical fitness and mental health. The results, published in the journal Nature Mental Health, show that good cardiorespiratory fitness significantly reduces the risk of developing dementia, depression, and psychotic disorders.
Unlike subjective assessments of physical activity, the scientists focused on cardiorespiratory endurance—the ability of the heart and lungs to supply the body with oxygen during exercise. This indicator is considered one of the most accurate markers of overall physical fitness.
The team conducted a systematic review and meta-analysis of 27 large studies involving over 4 million people of various ages. The participants, who were free of mental disorders at the start of the study, were tested for physical endurance and then tracked for many years.
Cardiorespiratory training aims to increase maximal oxygen consumption. A combination of regular moderate-intensity aerobic exercise (running, swimming, cycling) and high-intensity interval training (HIIT) is effective, with sessions lasting at least 20–40 minutes.
The analysis revealed impressive results. High physical fitness, compared with low fitness, was associated with a 39% lower risk of dementia, a 36% lower risk of depression, and a 29% lower risk of psychotic disorders. The risk of anxiety disorders was also reduced, although the association was less pronounced. “Even a small improvement in physical fitness, equivalent to an increase of 1 MET (resting energy expenditure), reduces the risk of dementia by 19% and depression by 5%,” adds Bizzozero Peroni.
The researchers emphasize that these data have significant public health implications. Cardiorespiratory fitness is a modifiable factor, meaning it can and should be improved. “These results support the idea of integrating fitness assessment into routine medical examinations, including mental health screening,” the researcher states.
In the future, the team plans to study the identified relationships across different age and ethnic groups around the world to make prevention programs as effective as possible.