This PhD project examines changing conceptions of physical exercise and bodily health in eighteenth-century France. Enlightenment culture in Europe provided an atmosphere of reform within which both society and individual were viewed as malleable. A new criterion of social utility governed discussions of health and education, and highlighted the unreformed status of certain sections of society. There was an understanding in France that urban life generally, and the urban elite in particular, had degenerated. The idleness of the gens du monde was considered a significant factor in the corruption of modern French society; the physical languor it produced was seen to render people useless to the nation. Fears surrounding depopulation and military weakness gave further impetus to calls for reform. Good health and the physical strength associated with it were perceived to key to the reversal of both urban decline and military fragility. The mother-to-be, the child and the noble officer were targeted in the drive to produce healthy, virtuous citizens. The thesis argues that a transformed conceptualization of physical education, emerging from a preoccupation with preventive medicine, was central to ideas regarding the health and strength of the nation. Drawing on manuals concerned with health and education, discussions of health in the press, polemics on the function of the nobility, and the correspondence of the Société Royale de Médecine, a distinct shift is traced in the ways in which exercise was discussed in the second half of the century. This was characterised by a view of exercise which focused upon adding strength and vigour, in contrast to earlier accounts which defined movement as a means of balancing or stabilizing what entered or exited the body.