Engaging in directed, programmed physical activity, or even promoting a more active lifestyle, is increasingly widespread.It is clear that the benefits of regularly engaging in these activities constitute a protective factor against the development of chronic diseases. 1These favorable effects can be seen in primary and secondary prevention in patients with heart failure, coronary disease or arterial hypertension, 2 and, more broadly, in any sedentary individual, with or without cardiovascular risk factors.In light of this, the number of people who may benefit from a personalized physical activity program is constantly growing, leading to a more frequent use of methods that streamline and facilitate the development of these programs.It is indispensable for healthcare professionals, and particularly physicians, to be able to provide recommendations regarding the best way to quantify the intensity of a given physical effort, as well as the proper use and measurement of heart rate (HR) as an indicator of this effort.Manual HR measurement may produce inaccurate results 3 and even at times require inter-