**Background:** Consumer health technologies (CHTs), including fitness and health apps, wearables, and self-tracking devices, are widely used worldwide—in the US in 2021, 59% of the general population tracked steps, 42% athletic performance, and 37% heart health. Despite promises of personalized healthcare, prevention, and empowerment, there is growing concern about unintended negative psycho-social effects such as stress, guilt, dependency, loss of intuitive body knowledge, and the widening of health inequalities. The authors note that while data security and privacy receive substantial public attention, psycho-social side effects are less discussed. This narrative review aims to assess these neglected negative effects, systematize them, and relate them to societal trends and user vulnerabilities.
**Methods:** A narrative literature review was conducted from February to April 2021, searching PubMed, Web of Science, Scopus, EBSCO (Sportdiscus), and Google Scholar. Papers in English or German were included with no restricted timeline. The review focused on three thematic areas: user types, unintended psycho-social side effects of CHT use, and societal trends. The narrative approach was chosen for its flexibility and appropriateness to inductive and qualitative research designs.
**Key Results:** Five user typologies were identified in the literature (Gerhard & Hepp, 2018; Mayer & Markopoulos, 2018; Kupfer, 2016; Seshagiri et al., 2016; Selke et al., 2021), distinguishing users by motivations, practices, and vulnerabilities. Additional scholars described use practices and motivations including fun/entertainment, performance improvement, hedonic/utilitarian/eudaemonic aims, and active vs. passive tracking. Three major societal drivers of CHT use were identified: (1) Economization and self-optimization—CHT use may lead to feelings of guilt, stress, failure, and obsessive self-optimizing behavior, with exercise dependency exacerbated in female users; (2) Datafication—risks include loss of intuitive body knowledge, feeling controlled by numbers, frustration from data-experience mismatches, anxiety, and dependency. In a study with chronic obstructive pulmonary disease patients, step counter users felt stressful pressure to exercise and had negative feelings about 'losing steps' when not wearing their device; (3) Individualization—social comparison via CHTs can be demotivating, and motivational dependency on CHTs was observed, stronger for those with low intrinsic motivation. Vulnerabilities arise from combinations of individual constitution, environmental factors, and social context. Socio-economic status is a key factor: individuals with higher income and education use CHTs more often, potentially widening health inequalities. The authors propose a new user typology with three dimensions: (a) attitude toward data (distanced-rational vs. identifying-emotional) and understanding of health (reductionist vs. holistic); (b) self-determinedness (self- vs. other-determined) and purpose (health-oriented vs. optimizing); (c) level of social interaction and individualization of technology.
**Clinical Implications:** The authors argue that current regulation and certification (e.g., Germany's DIGA process for health apps) is technology-centered and does not account for the diversity of users in real-world settings. They call for more systematic quantitative and qualitative research to establish correlations between user types, vulnerability factors (socio-demographics, gender, age, health status, education, psychological predisposition), and negative effects. Participative development of CHTs involving diverse user types, including minority and disadvantaged groups, is recommended. Concerted efforts by researchers, regulators, and developers are needed to raise awareness about ambiguous effects and enable informed user choices.