Under what conditions does exposure to difficult physical working conditions impact a person’s health condition ? To answer this question, the authors drew on the findings of the “Santé et itinéraire professionnel” (SIP – health and professional trajectory) survey. The first wave of this survey was conducted late 2006 as a series of face-to-face interviews with a representative sample of the general French metropolitan population. It targeted 13,700 persons aged 20 to 74, working and non-working. It included, notably, a retrospective review of each person’s professional biography and a more detailed evaluation of his or her health condition at the time of the survey. A multivariate analysis on the population over 50 years of age confirms the health impact of the studied exposures (night work, repetitive work, physically exhausting work, and exposure to harmful products). It reveals that a person’s education level has a protective effect in terms of both exposure risks and activity limitations. When the duration of exposures is factored into the analysis, a selective mechanism (the so-called “healthy worker effect”) emerges, which is particularly obvious in night work. Finally, multiple exposures have a significant effect on the deterioration of health at identical age and education level.