No. Whilst a number of activity monitors have included a heart rate sensor, heart rate is limited in its accuracy and reliability. The rationale for using heart rate monitoring as a measure of physical activity or energy expenditure relies on the linear relationship between heart rate and oxygen uptake, which is only good for a narrow range of activity. While the linear relationship exists for specific activities, i.e. dynamic moderate to vigorous intensity activities involving large muscle groups (Crouter, Albright and Bassett, 2004; Freedson and Miller, 2000), the relationship between heart rate and energy expenditure is weak at low activity levels (Montoye, 1996). There are also a number of other individual factors that affect this relationship, and getting a personalised understanding of this is a time consuming, labour-intensive, and expensive process, which is specific to the chosen physical activity modality (Eston and Reilly, 2001).