Review
Position statement on physical activity and exercise intensity terminology

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Abstract

The terminology used for monitoring and promoting physical activity and exercise among health and fitness professionals varies considerably. There is a large array of descriptor terms reported in the literature and used in day-to-day practice and this inconsistency can be confusing for clients and practitioners alike. The variation in terminology also makes it difficult to track changes in activity patterns over time and across studies. There are also a range of objective and relative intensity cut-offs used to describe the same intensity descriptors. This position statement addresses the question of standardisation of physical activity and exercise intensity terminology and makes recommendations that should assist those undertaking research and prescribing physical activity/exercise as well as those clients who are receiving professional guidance.

Introduction

Health and fitness professionals play important roles in helping to monitor and promote physical activity. Consequently the use of standard terminology related to physical activity and exercise among these professionals is important to ensure consistency of care and for collecting reliable data for research purposes.

Standard definitions of physical activity and exercise intensity are relevant to health and fitness professionals working in a variety of roles. This includes researchers working on the surveillance of physical activity and tracking trends over time, clinicians measuring health outcomes with activity prescription, and practitioners planning and guiding safe and effective exercise sessions.

There are also specific challenges and risks associated with exercise prescription such as when the exercise intensity exceeds an individual's physical capacity, or when a high relative intensity is prescribed in the absence of prior conditioning. These situations often need to be considered when working with people who have limited physical capacities, chronic illness or are engaged in rehabilitation programs.

This position statement addresses the question of standardisation of physical activity and exercise intensity terminology and makes recommendations that should assist those researching and prescribing activity as well as those clients receiving professional guidance. This, in turn, will assist the reliability of data collection on activity patterns and trends, and help in successful exercise prescription.

Section snippets

Categories of exercise and physical activity intensity

All physical activities result in energy expenditure ranging from the low levels of sedentary activities such as quiet sitting [generally referred to as 1 metabolic equivalent or 1 MET which is equal to 3.5 mL O2/kg/min] to the extreme levels of high-intensity exercise for conditioned athletes [from 9 to over 20 METs]. Essentially, there is a continuum of rates of energy expenditure across the many forms of movement, occupational and leisure-time activities. For convenience, analytical and exercise

Sedentary activity

Sedentary time is a relatively subjective term since the cut-off in intensity between sedentary and light activity levels has rarely been quantified. In general terms sedentary is derived from the Latin ‘sedere’ meaning ‘sitting’ so it usually incorporates almost all sitting-based activity. Pate and colleagues regard sedentary activities as having a metabolic equivalent level <1.6 METs.17 There have been many studies to show that long-term sedentary behaviours are associated with a variety of

Light-intensity activity

Light-intensity activities include domestic or occupational tasks such as washing dishes, hanging washing, ironing, cooking, eating, working at a computer desk or performing other office duties.15, 30 Operationally, light-intensity activities are those where the metabolic equivalent is between 1.6 < 3.0 METs or the relative intensity is 40 < 55% HRmax. These activities have been shown to be the major determinant of variability in total daily energy expenditure31 because they consume, on average,

Moderate-intensity activity

Moderate-intensity activities range from 3 < 6 METs or have a relative intensity of 55 < 70% HRmax. The AAS describes moderate-intensity activity as either ‘walking’ [for a duration of 10 min or greater] or ‘other activities’ such as ‘for example, gentle swimming, social tennis, golf’.24 The IPAQ is the same but includes the following examples ‘carrying light loads, bicycling at a regular pace, or doubles tennis’.26 Subjects wearing accelerometers showed that only a small fraction of the total day in

Vigorous-intensity activity

Most people in developed countries perform very little vigorous-intensity activity on a typical day.9, 22 Perhaps this is due to the reason that, using absolute measures, it requires between 6 and 9 times the resting levels of metabolism [6–9 METs] and involves considerable homeostatic disruption in the physiological systems. Vigorous-intensity activity is defined in the AAS as physical activity which ‘made you breathe harder or puff and pant—for example, jogging, cycling, aerobics, competitive

High-intensity activity

High-intensity activity has a relative intensity level of at least 90% HRmax. Using absolute measures, high-intensity activities are those requiring at least 9 METs. This rate of energy expenditure occurs very rarely in daily life. The Australian population averages for maximal oxygen uptake for age-and gender-specific groups,16 show this level of metabolism is above the maximal capacity of an estimated 35% of adults aged 18–29 year, 45% for 30–39, and over 50% of the rest of the population,

Summary

Researchers investigating patterns of physical activity behaviour, how people spend their time, the role of activity in energy balance, and how these variables trend over time and across regions need to standardise the way information is collected and analysed. Furthermore, there is also a need for greater consistency in terminology and intensity cut-offs for health professionals and their clients. This statement proposes five intensity categories and specific objective physiological and

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