The aim of the worksite study presented here is to elucidate the cortisol reducing impact of different ways of spending lunch breaks. With the help of the so-called silent room cabin concept it was possible to induce a relaxation opportunity that provides visual and territorial privacy. In order to evaluate its proposed effects, 14 call centre agents were distributed to either 20 min progressive muscle relaxation (PMR) or small talk break group. Participants were analysed in a controlled trial for a period of 6 months (1 day each month with five daily measurements at awakening, awakening +30 min, start of lunch break, end of lunch break, and bedtime) using saliva cortisol measurements as a stress indicator. Results indicated that only the PMR break reduced awakening, lunchtime, and bedtime cortisol response. Although further intervention research is required, our results suggest that post-lunch PMR may sustainably reduce participants' cortisol states in real worksite settings.