A device (1) for assisting with physical exertion management, includes a physiological sensor, a positioning device, at least one memory in which data representative of the itinerary to be travelled during the physical exertion can be recorded, and at least one data processing unit organised so as to produce forecast data representative of the change in an physical exertion parameter over the remaining itinerary to be travelled by the individual, to compare these forecast data with predetermined data, and to produce and transmit a message, the content of which depends on the result of the comparison of the forecast data and the predetermined data, with a view to communicating the message to a user.