A study conducted by the Faculty of Sport and Health Sciences at the University of Jyväskylä, Finland, found that men with a genetic predisposition supporting higher muscle strength had a lower risk of dying from cardiovascular diseases, regardless of their leisure-time physical activity levels or other lifestyle-related factors. Low muscle strength, particularly handgrip strength, has been linked to an increased risk of premature mortality. While physical activity can help slow the decline in muscle strength, higher muscle strength may also promote a greater willingness to remain active. Besides lifestyle factors, genetic factors play a role in muscle strength. A study at the University of Jyväskylä investigated whether a genetic predisposition to higher muscle strength is associated with lower all-cause and cardiovascular mortality in aging and whether leisure-time physical activity affects these associations. Inherited muscle strength linked to lower mortality risk in men, regardless of activity The results suggested that a genetic predisposition to higher muscle strength slightly lowered the risk of cardiovascular mortality in men. This association remained significant even after adjusting for other lifestyle factors such as smoking, alcohol consumption, and body mass index. Contrary to initial assumptions, the association between inherited muscle strength and the risk of death was not dependent on the amount of physical activity. The link between a greater inherited physical strength and a lower risk of death remained regardless of whether the person was more or less physically active in their leisure time." Päivi Herranen, doctoral researcher from the Faculty of Sport and Health Sciences Furthermore, the study found that a genetic predisposition to higher muscle strength did not lead to an increase in a person's physical activity. "Individuals who have inherited greater muscle strength through their genes do not automatically move more than others do," says Herranen. In women, an inherited predisposition to higher muscle strength was not associated with mortality, possibly due to biological and environmental differences between sexes that influence cardiovascular health. "Hypothetically, genetic and physiological factors that enhance muscle strength in women might also increase their susceptibility to cardiovascular diseases, the prevalence of which tends to rise with age," notes Herranen. "However, further research using larger datasets is needed to explore this potential link." Genetically determined muscle strength and lifestyle predict health risks The study utilized a polygenic score that combined the effects of hundreds of thousands of genetic variants associated with handgrip strength. The polygenic score enables comparisons between individuals with exceptionally high or low genetic predispositions to muscle strength, providing insights into its association with various health risks. Although the polygenic score for muscle strength alone has limited predictive power, it is comparable to the predictive power of several lifestyle factors. Further research is needed to explore the score's potential for integration into personalized risk assessments. "Moreover, the polygenic score for muscle strength could help determine whether an individual's genetic predisposition affects their response to exercise and their potential for improvement through training," Herranen adds. The study included genetic and lifestyle data of nearly 9000 participants from the older Finnish Twin Cohort. Information on participants' education, body mass index, smoking, alcohol use, and physical activity was collected via questionnaires at three measurement points. The study was awarded the second prize in the Best Research Paper in Sports Medicine Competition at the Helsinki Sports Medicine Days in 2024. It is the third publication of Päivi Herranen's doctoral dissertation, which investigates how genetics and environmental factors affect biological aging, particularly the weakening of muscle strength and functional capacity with age. The research is part of the GenActive project, funded by the Research Council of Finland and the Juho Vainio Foundation and Päivikki and Sakari Sohlberg Foundation. The project is led by Assistant Professor and Academy Research Fellow Elina Sillanpää. The research was conducted in collaboration with the Gerontology Research Center (GEREC) and the Institute for Molecular Medicine Finland (FIMM).