A sweeping new study from Sweden is challenging the widespread belief that higher physical fitness in young people directly leads to a substantially lower risk of premature death from diseases like cancer and heart disease—a notion that has shaped public health messaging globally, including in Thailand. The research, published in the European Journal of Preventive Cardiology (news-medical.net), reveals that previous studies may have overstated the true impact of physical fitness on mortality due to overlooked differences among individuals.
For many Thais, the message has been simple and constant: physical exercise, starting from a young age, translates into longer life and reduced risk of serious illnesses. This belief has supported initiatives ranging from school sports programmes to national campaigns promoting jogging in Bangkok’s parks and community aerobics sessions in rural provinces. But the new findings suggest the relationship is more complex, warning policymakers and the general public not to overestimate the preventive power of fitness alone.
Drawing on comprehensive data from conscription records of more than 1.1 million Swedish men, the Uppsala University-led study tracked their fitness levels at age 18 and monitored their causes of death up to their 60s. As expected from traditional analyses, those in the highest fitness group had a 58% lower risk of dying from cardiovascular disease, a 31% lower risk of dying from cancer, and a 53% lower risk of dying from all causes, compared with the least fit group. These dramatic numbers align with what many earlier observational studies have found.
But the study introduced a revealing twist. Using a method known as “negative control outcome analysis,” the researchers examined deaths from random accidents—such as car crashes, drownings, and homicides—assuming that there should be no direct link between cardiorespiratory fitness in adolescence and risk of accidental death. To their surprise, the data showed that highly fit individuals were also much less likely to die from these random accidents—by as much as 53% compared to their less fit peers.
“People with high fitness levels in late adolescence had a lower risk of dying prematurely, for example from cardiovascular disease,” explained the study’s lead researcher, an associated researcher in epidemiology at Uppsala University. “But when we looked at their risk of dying in random accidents, we found an almost similarly strong association. This suggests that people with high and low fitness levels may differ in other important ways, which previous studies have not fully taken into account.”
This unexpected finding points strongly to “confounding factors”—hidden differences between groups that may bias results. For example, young people with higher fitness may also come from wealthier families, have better access to healthcare, practice more safety-conscious lifestyles, or be less likely to engage in risky behaviours like substance abuse. The researchers tried to adjust for variables like body mass index (BMI), parents’ income and education, and even used sibling comparisons to control for genetics and shared environment, but the strong association persisted.
Further, as noted by the study leader, this echoes results from previous twin and genetic studies, which have indicated that some of the same genes might make a person both more likely to exercise and to avoid disease, regardless of their exercise habits. “It surprised us that the association with accidental mortality reflected the other associations, even after we controlled for all the factors that siblings share. This underlines how strong the assumptions are that you make in observational studies, since it appears to be very difficult to create comparable groups,” the lead researcher noted.
In a Thai context, these findings are particularly important. The country’s government has invested heavily in mass exercise campaigns, encouraged physical education in schools, and used the benefits of fitness as a rallying cry against rising rates of noncommunicable diseases. Thai public health leaders and sports promotion officials routinely cite international research to justify investments in public fitness infrastructure. However, as this new study shows, the size of the effect of fitness on preventing early death may be smaller than previously imagined if confounding lifestyle, social, and genetic factors are not fully accounted for.
Thai experts have long recognized the complexity of promoting healthy lifestyles. A senior figure at Thailand’s Ministry of Public Health, speaking about policy planning, has previously acknowledged that “no single solution is sufficient. Community context, access to health information, and economic factors all matter.” This research underscores the vital need for multi-dimensional interventions rather than relying solely on exercise promotion.
Culturally, Thais have a tradition of combining physical activity with social cohesion, seen in community Muay Thai gatherings, evening group exercises in front of temples, and rural cycling clubs. While these practices promote heart health and well-being, the study suggests public communication should be balanced, emphasizing overall healthy living—diet, mental health, accident prevention, and medical screening—rather than simply trusting that exercise alone offers complete protection.
Looking ahead, the Swedish researchers urge that population-wide health interventions—such as Thailand’s National Health Development Plan, which explicitly targets reduced disease mortality through increased activity—must anchor expectations in solid scientific estimates. “Our results should not be interpreted as if physical activity and exercise are ineffective or that you should not try to promote it,” said the lead author. “But to create a more nuanced understanding of how big the effects of fitness actually are on different outcomes, we need to use several different methods.”
For Thai policymakers, this may mean stepping up efforts to link fitness campaigns with other wellbeing strategies: strengthening road safety for young people, discouraging substance abuse, expanding access to preventive care, and ensuring that fitness messages do not replace holistic health promotion.
For ordinary Thai readers and families, especially parents, the message is equally relevant: encourage your children and loved ones to stay active for the many physical, social, and mental health benefits—enjoying sports, moving together, and reducing sedentary behaviour all have value. But also remember the importance of other pillars of good health: balanced nutrition (the wisdom of traditional Thai diets rich in vegetables and herbs), road and water safety, regular checkups, and avoiding high-risk behaviours.
In conclusion, while the allure of a simple, powerful message—“get fit, live longer”—remains popular, responsible health promotion in Thailand and elsewhere must reflect the growing sophistication of scientific understanding. Physical activity is vital, but it is only one part of living a long, healthy, and meaningful life. As new studies like this make clear, no single factor can guarantee protection, and balanced, evidence-based approaches remain the cornerstone of Thailand’s public health future.
Sources: news-medical.net, European Journal of Preventive Cardiology, World Health Organization – Physical Activity Fact Sheet, Thai Ministry of Public Health.