Researchers from the Karolinska Institute report that body weight in late teens has a stronger link to future cardiovascular disease risk than the level of physical activity. The findings were published in a major medical journal, highlighting a shift in how young people should approach long term heart health.
Over the years, many studies have connected lifestyle choices made early in life with risks for heart disease later on. Diet, exercise, alcohol use and smoking have all appeared repeatedly as factors that shape cardiovascular outcomes. Yet these studies often struggled to prove a clear cause and effect because they did not fully account for inherited traits and the environment in which individuals grow up. The new work addresses that gap by using a unique study design and an extraordinarily large dataset.
The team analyzed data from more than one million men tracked for six decades. A key feature was that nearly half of the participants were full siblings. This design helped to separate the influence of genetics from other factors and to more accurately estimate the impact of body weight on health outcomes. The analysis showed a consistent pattern: higher body weight during late adolescence was strongly associated with a greater risk of cardiovascular disease later in life, even after adjusting for other variables such as lifestyle, socioeconomic status, and family history.
In contrast, the link between physical activity during adolescence and later cardiovascular disease was present but noticeably weaker. This finding suggests that the long term benefits of activity may have been overstated in some prior studies when genetic and familial factors were not fully accounted for. Still, staying active remains valuable for overall health and well being, even if its direct impact on heart disease risk is not as large as once believed in isolation.
Lead researchers emphasized that this does not negate the importance of fitness. Ahlqvist and colleagues noted that activity still correlates with health outcomes after certain adjustments, but the strength of the association diminishes when siblings and shared environments are taken into account. The main takeaway centers on weight management as a key lever in reducing cardiovascular risk. When health systems prioritize strategies to prevent obesity and support healthy weight across adolescence, the potential for lasting heart health improvements grows stronger.
Thus, while activity should not be dismissed, efforts to curb the rising obesity rates among young people could have the most substantial public health impact in the long run. Programs that encourage balanced nutrition, regular movement, and favorable environments for weight control may help shift the trajectory of cardiovascular disease risk at the population level. This study adds a crucial layer to the growing evidence base, reinforcing the idea that early prevention can yield meaningful benefits as people age.
Overall, the research highlights the importance of a comprehensive approach to adolescent health. Weight management, healthy eating patterns, and opportunities for safe, enjoyable physical activity together form a foundation for better heart health across the lifespan. As scientists continue to explore the complex interplay of genetics, behavior, and environment, it becomes clearer that addressing weight in adolescence could be a primary strategy in reducing the burden of cardiovascular disease in adulthood. The findings invite policymakers, clinicians, and families to consider how early life interventions can shape longer, healthier lives for people in North America and beyond.