Physical Inactivity = Growing Obesity + Mental Health

 

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I recently conducted a peer review of an article by Santos et al. (2023).  The article's title is "The cost of inaction on physical inactivity to public healthcare systems: a population-attributable fraction analysis," and it was published in The Lancet Global Health. My assessment of the study is that it provides a compelling analysis of the health and economic consequences of physical inactivity, projecting that nearly 500 million new cases of preventable non-communicable diseases (NCDs) and mental health conditions will emerge globally by 2030 if current trends persist, incurring direct health-care costs of approximately $520 billion. For professionals and policymakers in the United States, where obesity rates have soared to over 40% of adults (CDC, 2023), this research is not just informative; it is a call to action. I explore why this information is essential in the USA’s growing obesity epidemic, weaving together empirical evidence and scholarly insights to underscore the urgency of addressing physical inactivity.

Obesity and physical inactivity are inextricably linked, forming a vicious cycle that amplifies the prevalence of NCDs such as coronary heart disease, type 2 diabetes, hypertension, and certain cancers, all conditions highlighted in the analysis by Santos et al. (2023). In the USA, the tripling of obesity rates since the 1970s (CDC, 2023) coincides with a societal shift toward sedentary lifestyles driven by technological advancements, urban sprawl, and a predominance of desk-based occupations. Santos et al. (2023) emphasize that physical inactivity is not merely a byproduct of obesity but a significant driver, contributing to 499.2 million new preventable cases globally by 2030, with hypertension (47%) and depression (43%) leading the tally. In the American context, where obesity-related diseases strain the health-care system, this dual burden underscores the need for interventions that target physical inactivity as a root cause. The researchers focused on incidence-based costs, estimating the economic impact of new cases rather than existing prevalence, and offered a forward-looking perspective that was critical for the USA. By 2030, the projected annual cost of inaction globally is $47.6 billion, with high-income countries like the USA bearing 63% of the economic burden despite hosting fewer new cases (25%) compared to low- and middle-income countries (LMICs) (74%). This disparity reflects the USA’s exorbitant healthcare costs, where spending nears 18% of the GDP (CMS, 2023). For instance, while dementia accounts for only 3% of new preventable cases, it consumes 22% of costs due to its intensive treatment demands, a pattern likely magnified in the USA’s advanced medical system. Therefore, addressing physical inactivity is not just a health imperative but an economic necessity to curb the escalating costs of obesity-related conditions.

The economic argument presented by Santos et al. (2023) resonates deeply in the USA, where the financial toll of obesity-related diseases is staggering. The study is finding that high-income countries will shoulder a disproportionate economic burden—63% of the global $520 billion—which mirrors the USA’s reality, where healthcare expenditures dwarf those of LMICs due to costly diagnostics, pharmaceuticals, and specialized care. This misalignment between case numbers and costs (e.g., cancers at 1% of cases but 15% of costs) highlights a critical inefficiency: the USA spends heavily on treatment rather than prevention. As a modifiable risk factor, physical inactivity offers a cost-effective leverage point. The WHO estimates that every $1 invested in scaling up NCD prevention yields up to $7 in returns in LMICs (Santos et al., 2023).

Beyond physical NCDs, Santos et al.’s inclusion of mental health conditions—depression (43% of new cases) and dementia (22% of costs)- adds a vital dimension to the obesity discussion in the USA. The post-COVID-19 surge in mental health disorders (WHO, 2022) has exacerbated an existing crisis, with physical inactivity serving as a common thread linking obesity and psychological well-being. Research consistently shows that physical activity mitigates depression and slows cognitive decline, offering a dual benefit in a nation grappling with both obesity and mental health challenges. In the USA, where social isolation and economic stress have intensified these issues, integrating physical activity into public health strategies could address this overlooked comorbidity, reducing human suffering and economic strain. The study’s alignment with the WHO Global Action Plan on Physical Activity 2018-30 provides a blueprint for the USA, advocating multisectoral interventions such as urban planning for walkability, enhanced recreational access, and school-based physical education. However, Santos et al. (2023) caution that infrastructure alone is insufficient; behavioral change requires culturally tailored, evidence-based approaches. In the USA, where obesity disproportionately affects marginalized communities, policies must address systemic barriers, e.g., lack of safe public spaces or time constraints from multiple jobs and access to proper nutrition. A significant segment of the population has been consumed by ultra-processed foods, which is one of the leading indicators of the growth in obesity rates globally.

My professional assessment is that Santos et al. (2023) perfectly frame physical inactivity as an avoidable crisis, an indispensable perspective for the USA amid obesity epidemics. With only eight years to meet the Sustainable Development Goal of reducing NCD mortality by 2030, the evidence is clear: inaction will perpetuate a health decline and economic loss cycle. As a longtime health and fitness coach, I conjecture that health practitioners prioritize physical activity not as a luxury but as a cornerstone of public health policy. The cost of doing nothing—in dollars and lives—is too high.

References

Centers for Disease Control and Prevention (CDC). (2023). Adult Obesity Facts.

Centers for Medicare & Medicaid Services (CMS). (2023). National Health Expenditure Data.

Santos, A. C., et al. (2023). The cost of inaction on physical inactivity to public health-care systems: a population-attributable fraction analysis. The Lancet Global Health, 11(1), e32- e39.

World Health Organization (WHO). (2022). Mental health and COVID-19: Early evidence of the pandemic’s impact.