While the Quantified Self has often been described as a contemporary iteration of Taylorism, this article argues that a more accurate comparison is to be made with what Anson Rabinbach has termed the "European Science of Work." The European Science of Work sought to modify Taylor’s rigid and schematic understanding of the laboring body through the incorporation of insights drawn from the rich European tradition of physiological studies. This "softening" of Taylorist methods had the effect of producing a greater "isorhythmia" or synchronicity between the bodily rhythms of workers and those of the mode of production itself and was embraced by employers as a way to dampen worker militancy. Through a discursive analysis of the promotion of sensor analytics by management consultants VoloMetrix and Humanyze, I argue that the contemporary quantification of the workplace represents a similar project of "soft domination," as the intimate, bottom-up mode of surveillance it fosters seeks to more closely mold workers’ physiological and social rhythms to the structure of the workplace and the working day.