Daily physical activity as determined by age, body mass and energy balance.

Klaas R Westerterp

doi:10.1007/s00421-015-3135-7

Abstract

AimInsight into the determinants of physical activity, including age, body mass and energy balance, facilitates the design of intervention studies with body mass and energy balance as determinants of health and optimal performance.MethodsAn analysis of physical activity energy expenditure in relation to age and body mass and in relation to energy balance, where activity energy expenditure is derived from daily energy expenditure as measured with doubly labelled water and body movement is measured with accelerometers, was conducted in healthy subjects under daily living conditions over intervals of one or more weeks.ResultsActivity energy expenditure as a fraction of daily energy expenditure is highest in adults at the reproductive age. Then, activity energy expenditure is a function of fat-free mass. Excess body mass as fat does not affect daily activity energy expenditure, but body movement decreases with increasing fatness. Overweight and obesity possibly affect daily physical activity energy expenditure through endurance. Physical activity is affected by energy availability; a negative energy balance induces a reduction of activity expenditure.ConclusionOptimal performance and health require prevention of excess body fat and maintenance of energy balance, where energy balance determines physical activity rather than physical activity affecting energy balance.

Highlights

The energy cost of physical activity, as determined by body movement, is the most variable component of daily energy expenditure (Starling 2002)
To approach these research questions, analyses of daily physical activity in relation to age, body mass and energy balance are performed for studies where activity energy expenditure is derived from doubly labelled waterassessed daily energy expenditure (Speakman 1997) and body movement is measured with accelerometers (Westerterp 2009)
Energy expenditure divided by resting energy expenditure adjusts for subject characteristics, resulting in a dimensionless figure allowing for comparison of activity levels between subjects differing in body size and body composition

Summary

Introduction

The energy cost of physical activity, as determined by body movement, is the most variable component of daily energy expenditure (Starling 2002). Insight into the effects of age, body mass and energy balance on daily physical activity facilitates the design. To approach these research questions, analyses of daily physical activity in relation to age, body mass and energy balance are performed for studies where activity energy expenditure is derived from doubly labelled waterassessed daily energy expenditure (Speakman 1997) and body movement is measured with accelerometers (Westerterp 2009). The doubly labelled water method is considered the gold standard for measuring daily energy expenditure under field conditions (Shephard and Aoyagi 2012). It allows measuring energy expenditure in unrestrained individuals over a time interval of 1–4 weeks. Accelerometers provide additional information on body movement with regard to the amount and intensity over much shorter intervals, usually minutes, to assess activity patterns throughout days and weeks

Methods of measuring daily physical activity

Findings

Discussion and conclusions