Being physically healthy can have lifelong benefits that protect your brain and mind. Recent research published in natural mental health It has been suggested that higher levels of cardiovascular fitness are associated with a lower risk of developing conditions such as depression and dementia. These findings provide evidence that keeping the heart and lungs in good shape may be an important part of maintaining long-term mental health.
Scientists conducted this study to address gaps in our understanding of how physical health affects the brain. Cardiorespiratory fitness measures how well your body absorbs and utilizes oxygen during sustained physical activity. Previous research on this topic has combined only a few studies at a time and focused primarily on adults with anxiety or depression.
Valentina Díaz Goni and Bruno Bizzozero Peroni from the Center for Health and Social Research at the University of Castilla-La Mancha in Spain explained the motivation behind the study. In addition to the center, Bizzozero Peroni is affiliated with the Karolinska Institute in Sweden and the University of the Republic in Uruguay. They wanted to look at the entire life span to understand whether fitness could prevent less common problems such as psychotic disorders.
“This study arose from a growing interest in understanding mental health from a preventive and integrative perspective,” the researchers said. “Physical activity has long been associated with improved mental health, but we thought we needed to focus specifically on cardiovascular fitness. They aimed to synthesize the available evidence across multiple psychiatric and neurocognitive disorders to better understand how strongly fitness levels are associated with long-term mental health outcomes.
To investigate this, scientists performed a systematic review and meta-analysis. Meta-analysis is a statistical method that combines data from multiple independent studies to identify overall trends. The researchers searched five major scientific databases for cohort studies, which are studies that follow a specific group of people over time.
They specifically looked for studies in the general population that did not have psychiatric or neurocognitive disorders at the start of the study. The research team found 27 relevant studies published between 2009 and 2025. These studies followed a large combined sample of 4,007,638 people from nine countries.
Participants came from countries such as the United States, United Kingdom, Sweden, Norway, and Taiwan. The majority of these individuals were classified as being of Caucasian or European ancestry. The average age of participants at the start of the study was approximately 10 to 72 years, and they were monitored from 4 to 29 years of age.
Initial studies used a variety of testing methods to measure cardiorespiratory fitness. Some studies used oxygen consumption tests directly in a laboratory setting. Other studies relied on indirect exercise performance tests on a treadmill or stationary bike.
This data reveals that high levels of cardiorespiratory fitness are associated with a significantly lower risk of developing certain psychiatric and neurocognitive disorders. Specifically, people in the highest fitness category had a 36% lower risk of developing depression than those in the lowest fitness category. High fitness was also associated with a 39% lower risk of developing all-cause dementia.
Researchers found that individuals with good health had a 29 percent lower risk of developing schizophrenia spectrum disorders and other psychotic disorders. This particular finding was based entirely on data from two studies that included only male participants. For anxiety disorders, pooled data did not show a statistically significant protective effect of higher fitness.
By looking at incremental changes, scientists found that even small gains in fitness can be beneficial. “One notable finding was how consistent the associations were across different diseases, particularly depression and dementia,” the researchers explained. “We were also struck by the fact that even modest improvements in fitness, such as improved 1-MET, can lead to measurable reductions in risk.”
“MET (Metabolic Equivalent Task) is a simple way to express energy expenditure. One MET represents the energy expended at rest, and approximately twice that amount is required for light activity such as slow walking,” they added. “This strengthens the idea that small, achievable changes can have important long-term health benefits.” It was found that just one metabolic equivalent increase in a person’s fitness capacity was associated with a 5 percent lower risk of depression and a 19 percent lower risk of dementia.
Researchers suggest several biological reasons why physical fitness may protect the brain. Exercising and improving your fitness increases blood flow to your brain and reduces inflammation throughout your body. Chronic inflammation is known to damage brain cells and disrupt chemical signals associated with mood and memory.
Higher fitness is associated with maintaining hippocampal volume over time. The hippocampus is a specialized brain region responsible for memory formation and emotional regulation. Fitness may also support the health of the brain’s white matter, which acts as a communication network connecting different regions of the brain.
“The key message is that improved cardiorespiratory fitness is associated with a significantly lower risk of developing diseases such as depression, dementia, and psychiatric disorders,” researchers told PsyPost. “Importantly, the benefits are not limited to people who are physically fit; even small improvements in fitness can make meaningful changes. This suggests that incorporating regular physical activity into daily life is a powerful and accessible way to support both physical and mental health.”
Although these findings suggest a protective role for physical fitness, there may be some misconceptions and limitations that should be considered. The certainty of evidence for depression, anxiety and psychiatric disorders was rated as very low. Meanwhile, evidence of dementia was rated as moderate.
One of the major challenges in this type of research is the possibility of reverse causation. Reverse causation means that early, undetected symptoms of a mental health condition can actually cause a person to become less physically active. This lack of motivation tends to lead to a decline in fitness before a formal diagnosis is made.
When asked about limitations, the researchers acknowledged that there are some. “Most of the available evidence comes from middle-aged adults in Europe and North America, so further studies targeting younger people, older adults, and more diverse global settings are needed,” the researchers explained. “Furthermore, although the associations we observed are consistent, they must be interpreted with caution because observational studies cannot establish definitive causal relationships.”
They also highlighted the lack of data on specific conditions. “Evidence is also limited for several other psychiatric disorders, such as bipolar disorder, stress-related disorders, sleep-wake disorders, and ADHD, and there are no studies available for some disorders, such as autism spectrum disorder,” the researchers noted. “This means that conclusions in these areas are still uncertain and further research is needed to fill important gaps in the evidence.”
Future research should continuously track both fitness and mental health over time to better understand which changes first. Researchers have concrete plans to move the field forward. “Going forward, we aim to expand this study to underrepresented populations and conduct longer-term studies to better clarify causal relationships,” they said.
“We are also interested in exploring the biological mechanisms underlying these associations, including inflammation, brain plasticity, and stress regulation, to better understand how fitness influences mental and neurocognitive health over time,” they added. Scientists believe their research provides practical insights to society.
“Overall, we believe these findings highlight cardiorespiratory fitness as a modifiable and scalable factor that may play an important role in public health strategies,” the researchers concluded. “Improving physical fitness has the potential to not only help people live longer, but also improve quality of life by reducing the risk of mental disorders and cognitive decline.”
The study, “Cardiorespiratory fitness and the risk of mental disorders and dementia: a systematic review and meta-analysis,” was co-authored by Valentina Díaz Goni, José Francisco López Gil, Eva Rodríguez Gutiérrez, and María Euge Nia Vizier Alfonso, Estela Jiménez López, Jose Castro Pinero, Arthur Yuman Mesas, Mairena Sánchez López, Vicente Martínez Vizcaino, Bruno Bizzozero Peroni.
