ABSTRACT
Heart rate is one of the most important and most studied variables in sports and exercise science. Over the years, hardware and software have been developed that allow its validation in a valid and reliable way. Currently, due to this information technology development, there are devices such as skin patches, electrodes, chest bands, oximeters, wristbands, smart watches, implanted devices, and other devices that allow monitoring the heart rate with wearable technology. This technology is characterized by its high capacity, portability, flexibility, good looks and design and accessibility. Hand in hand with commercial and technological development, the scientific community has been interested in testing the validity and reliability of these wearable systems. In this sense, there is ample evidence on validity and reliability from acceptable to excellent when compared with the electrocardiogram data as a criterion. Today, heart rate in combination with mechanical sensors has been shown to accurately estimate energy expenditure during certain activities. That is why the assessment of both variables simultaneously can provide complementary and highly relevant information for the planning and prescription of physical exercise.
