Public health agencies are asked to solve an intimidating array of problems. Unfortunately, they cannot address adequately all of the pressing needs, especially during times of declining budgets. The central argument of this commentary is that physical inactivity is one of the leading causes of poor health in the United States and worldwide, and a proportional response is justified but requires a thorough reconsideration of the priority of physical activity in public health.

* Fourth leading cause of death in the United States1 and globally.2

* Accounts for about 2.4% to 5% of annual health care costs in the United States.3

* Major risk factor for premature mortality, cardiovascular diseases, type 2 diabetes, some cancers, and depression, among many other health impacts.4

The need for public health action is further demonstrated by prevalence estimates of meeting physical activity guidelines among US adults ranging from about 5% (measured objectively) to 50% (measured by survey).5 If an in-between value of 25% is adopted, that means 75% of adults are at risk due to physical inactivity. This is much higher than the prevalence of smoking, high blood pressure, obesity, or problem drinking,1,6 and there has been very little change in meeting guidelines.7 In the 16 years since the 1996 Surgeon General's report on physical activity, an estimated 3.2 million Americans have died because of insufficient progress in increasing physical activity (16 years x 200 000 deaths per year).1

There is consensus that physical activity should be increased in the United States6 and globally,8,9 and effective interventions are available. The Guide to Community Preventive Services has documented that several intervention approaches targeted at individuals, social groups, and built environments can be effective.10,11 Almost all of these intervention approaches are considered cost-effective.12

Although there are many and growing efforts, it is clear that the public health response to physical inactivity has not been proportional to the burden.13 For research, there is no person or office at the US National Institutes of Health responsible for physical activity. Incredibly, though the National Institutes of Health tracks spending on more than 300 topics, the fourth leading cause of death is not among them.14 The Centers for Disease Control and Prevention supports state public health practice, but the Physical Activity and Health Branch is small compared with many branches responsible for issues with less documented health impact. Many state health departments have only a single physical activity specialist. The largest commitment to physical activity intervention has been the recent federally funded Communities Putting Prevention to Work15 and Community Transformation Grants.16 These major projects promote physical activity as part of obesity prevention and they are building capacity for physical activity intervention, but the response is still insufficient.

Why Has the Public Health Response Been So Limited?

There are several likely reasons.13 Compared with long-standing health priorities, such as infectious diseases and tobacco control, physical activity is a new entry on the public health agenda. Epidemiologic evidence on physical activity was limited until the late 1970s, so most public health leaders have had no training in physical activity. The reality is that health problems must compete for limited funding, and other topics have much larger and well-organized constituencies with ongoing programs that advocate effectively for their missions.

A defining characteristic of physical activity promotion is that it must involve multiple sectors of society. Physical activity is affected by actions, policies, and environments that are outside of public health, including city planning, transportation, parks and recreation, education, and business interests including entertainment, real estate, and automobiles.17 These sectors are generally unfamiliar to public health professionals, creating barriers to effective partnerships.

Recommendations

Progress in improving health in the United States and globally will require building expertise and capacity in physical activity.18 Here are recommendations for creating a more appropriate response to the challenge of physical inactivity.

* Ensure that all schools of public health offer courses in physical activity and health as well as physical activity interventions.

* Seriously consider the redistribution of public health budgets and staffing so that they match current realities about the dominance of noncommunicable diseases.

* Establish a physical activity coordinating office at the National Institutes of Health.

* An efficient approach would be to combine agendas with compatible public health programs. For example, injury prevention and physical activity groups could pursue built environment changes that contribute to both goals, promotion of active transportation can reduce carbon emissions, and obesity prevention should equally emphasize healthy eating and active living.

* Ensure that surveillance systems not only include quality measures of physical activity but also track related factors such as built environments, policies, and psychosocial correlates.

* Prioritize implementation, dissemination, and evaluation of evidence-based physical activity interventions at the individual, social, built environment, and systems levels.10,11

* Create partnerships with other sectors to leverage their resources to promote physical activity as well as achieve their core goals.

The recommended overarching objective is to create a response to physical inactivity in each public health agency that is proportional to the well-documented scope of the problem.

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