Physical inactivity – A worldwide pandemic

Coinciding with the London Olympics and the Paralympics, The Lancet medical journal in Britain has been publishing a series of papers on the worldwide problem of physical inactivity.

More than 50 health professionals and others, including university researchers, contributed to the series, which included topics such as “Technologies for Global Health”, “The Pandemic of Physical Inactivity”, “Why Some People are Active and Others are Not”, and “Sport and Exercises as Contributors to the Health of Nations”.

One of the papers, “Global Physical Activity Levels: Surveillance, progress, pitfalls, and prospects”, presents new estimates on current levels of physical activity and trends worldwide, alongside analyses that quantify the global impact of physical inactivity on the world’s major non-communicable diseases.

Globally, a third of adults, or about 1.5 billion people, and four out of five adolescents, are failing to do recommended amounts of physical activity, placing them at 20%-30% greater risk of heart disease, diabetes, and some types of cancer.

The series also reviews evidence-based strategies for effective physical activity promotion, and how a multi-sector and systems-wide approach that goes way beyond health is critical in order to increase population levels of activity worldwide.

“Societal trends are leading to less not more activity than previously, [and] with few exceptions, health professionals have been unable to mobilise governments and populations to take physical inactivity sufficiently seriously as a public health issue,” said Dr Pedro C Hallal, from the Universidade Federal de Pelotas in Brazil.

In the fifth paper, “The Pandemic of Physical Activity – A call for global action”, Dr Harold W Kohl from the University of Texas Health Sciences Center said the role of physical inactivity continued to be undervalued despite more than 60 years of evidence of its protective effects and the alarming cost burden associated with current levels of physical inactivity worldwide.

Kohl said that The Lancet series highlighted the incomplete and unfocused response to physical inactivity in most countries, saying research into this risk factor had often been understaffed and underfunded, compared to other risk factors for non-communicable diseases.

In a paper titled “Correlates of Physical Activity: Why are some people physically active and others not?”, researchers noted that physical inactivity was an important contributor to non-communicable diseases in countries of high income – and increasingly so in those of low and middle income.

“Understanding why people are physically active or inactive contributes to evidence-based planning of public health interventions, because effective programmes will target factors known to cause inactivity,” the researchers said.

“Research into correlates (factors associated with activity) or determinants (those with a causal relationship) has burgeoned in the past two decades, but has mostly focused on individual-level factors in high-income countries.

“It has shown that age, sex, health status, self-efficacy and motivation are associated with physical activity. Ecological models take a broad view of health behaviour causation, with the social and physical environment included as contributors to physical inactivity, particularly those outside the health sector, such as urban planning, transportation systems, and parks and trails.”

The paper says new areas of determinants research have identified genetic factors contributing to the propensity to be physically active, and evolutionary factors and obesity that might predispose to inactivity, and have explored the longitudinal tracking of physical activity throughout life.

An understanding of correlates and determinants, especially in countries of low and middle income, could reduce the effect of future epidemics of inactivity and contribute to effective global prevention of non-communicable diseases.