Despite the prevalent use of gamification in the health management context, its “dark side” for users remains unknown. To fill this research gap, we used the person–environment fit (P-E fit) model to build a theoretical model to explore the influences of gamification characteristics on stressors (privacy invasion and social overload) and strain (gamification exhaustion) for individuals. A survey was conducted to test our research model and all hypotheses. This paper gathered survey data through the Wenjuanxing website, a popular online survey platform in China. A total of 407 questionnaires were collected. The empirical results indicated that the competitive element and interactivity of gamification are positively associated with privacy invasion and social overload, which can cause gamification exhaustion. Further, we found that users’ health condition negatively moderates the relationship between gamification characteristics and stressors. Our research contributes to understanding of the dark side of gamification in the health management context. Our findings also contribute to the P-E fit model and literature on gamification, and provide new insights and implications for users and designers of health management platforms.