At the workplace stress and strain may occur, which can have negative effects on the organism. Stress can have a positive impact, but stress can also have negative effects on our health. It can not be dismissed, that it is necessary to find effective interventions to reduce stress to maintain our health. The study about the effect of stress interventions on the perceived physical and mental stress level of the office employees of the transport company Eurotransline lasted ten weeks. The participants in this study received either three times per week (during working time) a relaxation session (progressive muscle relaxation), sports (endurance training) or they were assigned to no intervention (control group). The process has been documented over five times. In addition to some questionnaires, at the physiological level, the cortisol awakening response and heart rate variability were collected. We couldnt find any significant changes in the heart rate variability and to the perceived level of chronic stress depending of the resulting intervention. As to the cortisol awakening response, a significant effect could be found. The cortisol concentration decreased from the first to the second and from the first to the third time of measurement. Primarily because of the results of the cortisol awakening response the assumption, that interventions to reduce stress are useful, can be supported.