Physical activity

Physical activity is defined as any movement produced by skeletal muscles that requires energy expenditure. Physical activity encompasses all activities, at any intensity, performed during any time of day or night. It includes both voluntary exercise and incidental activity integrated into the daily routine. This integrated activity may not be planned, structured, repetitive or purposeful for the improvement of physical fitness, and may include activities such as walking to the local shop, cleaning, working, active transport etc.

Lack of physical activity is associated with a range of negative health outcomes, whereas increased physical activity can improve physical and mental health, as well as cognitive and cardiovascular health. There are at least eight investments that work to increase population-level physical activity, including whole-of-school programmes, active transport, active urban design, healthcare, public education and mass media, sport for all, workplaces and community-wide programmes. Physical activity increases energy expenditure and is a key regulator in controlling body weight (see Summermatter cycle for more). In human beings, differences among individuals in the amount of physical activity have a substantial genetic basis.

"Exercise" and "physical activity" are frequently used interchangeably and generally refer to physical activity performed during leisure time with the primary purpose of improving or maintaining physical fitness, physical performance, or health. However, physical activity is not exactly the same concept as exercise. Exercise is defined as a subcategory of physical activity that is planned, structured, repetitive, and purposeful in the sense that the improvement or maintenance of one or more components of physical fitness is the objective. Conversely, physical activity includes exercise but may also be unplanned, unstructured, random and non-purposeful carried out for a multitude of reasons.

A 2021 study shows that people who start successful physical activity programmes maintain much of it for at least three months.

Physical activity can be at any intensity, ranging from a little muscle twitch to a full-out sprint. Physical activity can be thought of as a continuum in practice, ranging from inactive lifestyles to high-intensity exercises. Intensities are broadly categorized according to energy expenditure using a standard measure of intensity, metabolic equivalents (METs). The broad categories are sedentary behavior, light activity, moderate activity, and vigorous activity.

The following table documents some examples of physical activities at each intensity level. Depending on the individual and the activity involved, activities may overlap intensity categories or change categories completely.

Physical activity is a cornerstone of public health and prevention of non-communicable disease. Physical inactivity has been found to cause a wide range of non-communicable diseases, including coronary heart disease, stroke, diabetes mellitus and depression. An analysis of the healthcare costs of non-communicable diseases and mental illness attributable to physical inactivity for 2020–30 found that 500 million new cases of disease will occur globally between 2020 and 2030 if physical activity remains at today's levels. This corresponds to more than US$300 billion in treatment costs

As of 2024, 31% of adults and 80% of adolescents do not meet the recommended levels of physical activity.