The role of technology in contemporary society is immense, with technology being widely utilized in everyday life, both in the workplace and during leisure time. With the advent of the Internet of Things (IoT), many people have incorporated technology into their recreational activities, such as measuring their heart rate during jogging or monitoring their sleep quality at night. Excessive use of technology has been found to have detrimental effects on individuals, one of which is technostress. Technostress is stress arising from the use of technology, where stressors may include technological invasions or dependency on technology. Harmful effects of technostress include reduced productivity, anxiety, and other mental health issues. This thesis explores technostress, wearable technologies, and the impact of technostress in the relationship between the user and the application of wearable technology. The thesis aims to uncover answers to questions such as the technostress-related experiences of runners with their devices and the factors leading to these experiences. For instance, whether experiences resembling technostress result from the device's complex user interface or unreliable performance. The theoretical part of the research was conducted through a literature review, examining previous technostress studies and defining wearable technologies and influential technologies. The methodology involved qualitative methods, utilizing existing data from an online running forum and conducting interviews based on this data. Both datasets were analyzed using thematic analysis, influenced by Interpretative Phenomenological Analysis (IPA). The research results presented various themes related to the mechanisms of technostress in the context of wearable technologies and running, as well as different user types of wearable technologies based on the data.