Decreasing fitness levels can increase the risk of depression, anxiety, stroke, and dementia

Fitness was measured with a cycling test

The study analyzed data from 131,431 men over nearly five decades (1972–2020), using Swedish military service conscription records and health assessments from workplace health services. Fitness levels were measured at around 18 years of age (during conscription) and again in adulthood using a bicycle test, with an average of 25 years between the two tests. After the second test, participants were monitored for an average of eight years through medical records to see if they developed depression, anxiety, or conditions like stroke.

Reduced risk of disease

Key findings show that higher fitness levels in youth and adulthood are linked to a lower risk of developing these health issues later in life. Increasing fitness between the two-time points was also associated with a reduced risk of depression, anxiety, and cerebrovascular disease. On the other hand, a drop from moderate or high fitness during youth to low fitness in adulthood was linked to a 24–25 percent increased risk of depression and anxiety. Conversely, improving fitness from moderate in youth to high in adulthood was associated with a 16 percent lower risk of anxiety later in life.

Elin Ekblom Bak, Professor at GIH and project leader of the study, noted that this study is unique because it measured fitness at two different life stages for the same individuals, allowing researchers to explore how changes in fitness affected health outcomes. Moreover, all methods used to assess changes in fitness showed consistent results, strengthening the findings.

Difficult to find exact connections

However, Wiklund cautions that, as with all observational studies, it's difficult to establish cause and effect. The study only measured fitness at two points, meaning the full scope of fitness changes over time is not captured. This study did not account for additional factors, such as genetics, which could play a significant role. Also, since the study only involved men, the findings may only apply to some of the broader population.

Read the press release Word, 150.3 kB, opens in new window.

The study is published in the scientific journal American Journal of Preventive Medicine External link, opens in new window..

This study was conducted as part of E-PABS, a research center in physical activity, healthy brain functions, and sustainability, based at The Swedish School of Sport and Health Sciences.

HPI Health Profile Institute, AbbVie, BioArctic, and Monark Exercise participate as knowledge partners in the E-PABS research center.

Read more about Physical Activity and Brain Health, E-PABS External link, opens in new window. at GIH.