In recent years, the extension and the intensification of the working day, and the consequences of these changes have been the focus of study among a number of researchers and indeed, as pointed out by Burke (2009, p.167), “work hours has become a ‘hot topic’”. Although some of the results of this new development might generally be considered as positive for organizations and individuals, such as increased productivity (Green, 2001; 2004), most literature on the subject seems to concentrate more on the negative aspects and impacts of the process (Benson and Brown, 2005; Hewitt and Luce, 2006; Boltanski and Chiapello, 2007). Burnout resulting from the process (Barnett, Gareis and Brennan, 1999), psychological problems (Kirkcaldy, Levine and Shepard, 2000), family conflicts (Crouter et al., 2001), fatigue, irritability and increased accidents in the workplace (Dembe et al., 2005) are just some of the problems singled out by studies looking at the effects of an increase in the working day. It seems clear that the greater the intensity of the working day, the greater are the demands placed upon the worker, whether in physical, intellectual or psychological terms (Porter, 2001, 2004; Green; 2004; Burke and Fiskenbaun, 2009). However, from a worker’s point of view, this new work dynamic seems somewhat paradoxical, which leads us back to the question put by Burke (2009, p.169): “Why do people choose to work long hours?”. According to this author, some people need to have two jobs, just to survive. Others, on the other hand, have options (Burke, 2009). With regard to this second group, despite all these negative aspects associated with an increase in the intensity of the workload, as discussed in literature (McCann, Morris and Hassard, 2008), a number of researchers point to the existence of certain professionals who, even working long hours every day and at a frenetic pace, nevertheless state that they are happy at work (Green, 2004; Macky and Boxxal, 2008; Burke and Fiskenbaun, 2009).Thus, the fact that a process is underway which modifies the dynamic of how work is carried out, making it more intense and more prolonged, on the one hand, and the observation that a representative contingent of professionals appears to justify, and even in some cases, opt for working under such conditions on the other, have laid the foundations for this present study, which seeks to better understand both the work dynamic of these professionals, and what leads qualified professionals to work for organizations and in jobs that demand of them such intense dedication. In order to better understand this paradox (the dynamic of longer and more intense working hours versus professionals who actually choose to work under such conditions, and consider them satisfactory), this present and qualitative study carried out in-depth interviews with thirteen Brazilian professionals who work for organizations known for demanding high performance of their employees.