Published: 3.9.2026
Text: Heikki Sarin
Editing: Viestintätoimisto Jokiranta Oy
Images: Shutterstock

A substantial body of research demonstrates the key role of physical activity – as well as reductions in sedentary behaviour – in the prevention of cardiovascular disease and type 2 diabetes. The World Health Organization (WHO) has consistently highlighted the importance of physical activity. Within the EU alone, the costs of public-health conditions attributable to physical inactivity are estimated at €84 billion. According to meta-analyses, increased physical activity can reduce the risk of cardiac events by 15–20% across different baseline activity levels, and sufficient physical activity may substantially offset many of the health risks associated with sedentary behaviour.

Regular physical activity not only improves muscular fitness and supports weight control but may also influence health through less obvious pathways, such as the gut microbiome. Activities ranging from aerobic exercise and resistance training to reduced sedentary time (e.g., standing rather than sitting during work) have been linked to such effects. Indeed, research has shown an association between physical activity and microbial properties considered beneficial for human health, whereas inactivity has been linked to properties with adverse health outcomes.

How is the heart of a physically active person protected by gut microbiome?

Several earlier studies have shown that physical activity is associated with greater microbial diversity and a higher abundance of taxa considered beneficial for health. Conversely, studies on sedentary behaviour and physical inactivity have reported the opposite pattern.

Greater microbiome diversity has also been linked with better overall health. A more diverse microbiome is associated with greater capacity to, for example, produce health-maintaining metabolites, adapt to changes in living conditions, and prevent harmful microbes from gaining foothold in the human body.

The influence of the microbiome on human health is largely mediated through metabolites, that is, the products of microbial metabolism. Certain microbes are capable of producing metabolites with a direct beneficial or harmful effect on cardiac health. Correspondingly, lower microbial diversity is associated with, for example, cardiovascular disease.

Many earlier studies investigating the interaction between physical activity and the gut microbiome have been limited by small sample sizes, contradictory results, and insufficient consideration of important factors affecting the microbiome, particularly dietary factors. A more comprehensive and detailed approach to the topic is therefore warranted. By utilising a large, population-based dataset, our research project enables a comprehensive investigation of which properties related to the composition and function of the human gut microbiome are associated with physical activity, aerobic fitness and sitting time, as well as the risk of developing common public-health diseases, such as cardiovascular disease.

Toward tailored exercise and lifestyle recommendations

If predictors of cardiovascular disease risk can be identified among the microbiome properties associated with physical activity, it may become possible to develop more personalised and effective exercise and lifestyle recommendations in the future.

At best, such knowledge could help identify at-risk individuals at an early stage, when risks can be effectively and readily mitigated through suitable lifestyle changes. This could have a significant impact on both public health and the national economy, not to mention the quality of life of individuals.

 

Heikki Sarin, MD, PhD, MSc (Nutrition Science), is currently working as Chief Physician at Tampereen urheilulääkäriasema (Sports Medicine Centre in Tampere) and as a visiting researcher in the research programme for Clinical and Molecular Metabolism (CAMM), University of Helsinki.  He is also engaged in collaboration with the Faculty of Sports Medicine, University of Jyväskylä. Sarin’s research focuses on the role of physical activity, exercise and nutrition in the prevention and treatment of obesity and metabolic diseases. In particular, he is interested in factors related to weight control and the use of biomarkers in the prediction and management of health risks and health outcomes.