Chapter 1: Physical inactivity: a global public health problem

INTRODUCTION

Read any blog, newspaper, journal article or social media feed and you will find they are all telling you the same thing: physical inactivity is a problem—a big one. Physical inactivity causes alarming levels of chronic disease now; and the future predictions of societal costs and decimated quality of life are dire.

This is not new information. There have been calls to address the problem for decades. Global action plans and national strategies declared war on physical inactivity long ago, yet it seems many countries are still struggling to mobilise the troops. How many more times do we need to be reminded that physical inactivity is one of the leading risk factors for global mortality and is estimated to cause 3.2 million deaths annually,¹ before we finally decide to get off the couch?

The four previous editions of Clinical Sports Medicine shone a spotlight on the burden of physical inactivity and sedentary behaviour, but clinicians also appreciate the importance of other pressing behavioural contributors to health. As the World Health Organization (WHO) reminds us, unhealthy eating habits, tobacco consumption and harmful use of alcohol contribute to the tsunami of non-communicable disease (NCD). The concern, as Professor Steven Blair underlined so clearly in 2009, is that ‘the crucial importance of physical activity is undervalued and underappreciated by many individuals in public health and clinical medicine’.²

To raise awareness and provide the clinician with even more motivation to promote physical activity to their patients, family and friends, this chapter records the economic and health costs of physical inactivity. We outline some of the key policies and actions that could reverse downward trends. A global health problem of this magnitude demands a calculated, methodical and consistent plan of attack. To make progress we must first understand the problem.

PHYSICAL INACTIVITY TRENDS

The WHO Global Recommendations on Physical Activity advise that adults should do at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity throughout the week. Additionally, muscle-strengthening activities should be done at least twice weekly.³ While there are no global recommendations on sedentary behaviour, emerging consensus indicates it should be limited whenever possible.⁴

From an evolutionary perspective, humans are primed to move; daily hunting and gathering for survival necessitated continual movement and exertion. However, today, many in the wealthy West no longer need to run, climb or even walk to procure food and water (Fig. 1.1). Everything is available at the touch of a button.