How many calories do nurses burn at work? A real-time study of nurses’ energy expenditure

Abstract

Background: More than 50% of nurses do not meet recommended levels of physical activity and 50-65% are overweight or obese. While nursing is typically viewed as an active profession, few studies have objectively measured nurses’ activity levels during the working day. The present study aimed to quantify energy expenditure in nurses during typical shifts. Methods: Nurses (n=96; 90 female, mean age=36.4, mean experience=10.6 years, mean body mass index(BMI)= 26.6) participated in a real time study of energy expenditure over one working shift. Heart rate and activity level were measured using an Actiheart monitor and used in combination with body weight information to calculate energy expenditure (EE) in 15-second epochs. EE/15sec was then scaled to represent energy expended over a standard 12-hour shift. Data were descriptively summarised and multi-level modelling was used to examine patterns in energy expenditure over the working day. Findings: On average, nurses expended 1520 kcals over a 12-hour shift. When modelled over time, energy expenditure followed a cubic trend: rising initially at the beginning of the shift, then dropping mid-shift before increasing again towards the end of the shift. Energy expenditure was unrelated to age, grade/seniority or ward type (medical or surgical) but was significantly higher in nurses with a higher BMI (p<.01). Discussion: Nurses expend significant amounts of energy over a typical shift. Consequently, interventions aimed at helping nurses to achieve a healthy body weight may be better targeted at reducing food intake or increasing leisure activities than at increasing physical activity in the workplace.