(1) Background: As times change, the detection rate of hypertension is increasing in the young and middle-aged population due to prevalent sedentary behaviors. The purpose of this study was to conduct a scoping review to identify and summarize the research on sedentary behavior in this population by separating it into five stages: the relationship between sedentary behavior and health; measurement modalities; influencing factors; interventions; and translational research in young and middle-aged adults with hypertension. (2) Methods: Using a scoping review research approach, the PubMed, Web of Science Core Collection, and MEDLINE databases were used to search for the literature on this subject from the date of the database’s creation to 14 June 2022, and the behavioral epidemiology framework was used to classify the retrieved articles. (3) Results: A total of eight articles were included. Among them, there were six articles on the relationship between behavior and health, which includes blood pressure, insulin resistance, and the cardiovascular system; one article on the study of measurement methods, which was used for clinical decision making through decision trees; one article on influencing factors, which was divided into intrinsic and extrinsic factors; and no articles on intervention program development or the translation of intervention programs to further practice in this population. (4) Conclusions: Sedentary behavioral studies of young and middle-aged adults with hypertension are scarce and are generally carried out in the early stages of the condition. In the future, in-depth studies can be conducted on the dose–response relationship between sedentary behavior and health in this population; the development of easier and targeted measurement tools; the exploration of more influencing factors; and the effectiveness and translation of intervention programs.

(1) The formation pathways and underlying mechanisms of health behaviors among young and middle-aged adults with chronic diseases under a temporal perspective remain underexplored. Based on Temporal Self-Regulation Theory and its subsequent extensions, this study aimed to investigate the time perspective among Chinese young and middle-aged adults with chronic diseases and analyzed the relationships between time perspective, illness perception, health behavior motivation, and health behaviors, thereby providing valuable empirical evidence for health behavior modification in this population. (2) This study was a cross-sectional survey conducted from March to April 2025. Structural Equation Modeling was employed to investigate the relationships among the variables. (3) This study enrolled a total of 391 participants with high levels of future and past-positive perspectives. Time perspective, directly related to health behaviors, namely past-negative, present-impulsive, and present-fatalistic perspectives, exerted negative associations with health behaviors, respectively, whereas future and past-positive perspectives showed positive associations with health behavior. Analysis of the mediating effect found that illness perception served as a mediator between the time perspective of past-negative, present-impulsive, and present-fatalistic perspectives, and health behaviors. And health behavior motivation acted as a mediator in the relationship between past-negative, present-impulsive, and past-positive perspectives, and health behaviors. Furthermore, illness perception and health behavior motivation formed a chain mediation pathway between time perspective and health behaviors. (4) Time perspective was associated with health behaviors, not only exerting directed effects but also manifesting a double-edged sword effect through illness perception and health behavior motivation. Subsequent interventions targeting health behaviors among young and middle-aged populations in China should incorporate considerations of the temporal perspective’s uniqueness and its intricate mechanisms of action on health behaviors.