AIMS: The aim of this study is to verify the clinical validity of clinical indicators and aetiological factors of sedentary lifestyle in individuals with arterial hypertension. BACKGROUND: Diagnostic validation is performed to expand nursing taxonomies and to revise or confirm the described concepts. New elements listed in the literature and those identified by the NANDA International definition for sedentary lifestyle need to be evaluated. DESIGN: This is a cross-sectional and diagnostic validation study. The STROBE guidelines were used in this study. METHODS: Two hundred and fifty subjects aged over 18 years were evaluated. The diagnostic status of the participants was obtained by latent class analysis. Logistic regression was used to identify aetiological factors with the manifestation of sedentary lifestyle, considering a significance level of 5%. RESULTS: A total of 57.8% of the study participants met the diagnostic criteria for sedentary lifestyle. The clinical indicators with high sensitivity were as follows: "Average daily physical activity is less than recommended for gender and age"; "Does not perform physical activity during leisure time"; "Preference for activity low in physical activity" and "Overweight." The significantly related factors associated with the diagnosis of sedentary lifestyle were as follows: "Insufficient knowledge on physical activity," "Lack of time," "Negative self-perception of health," "Lack of security," "Lack of appropriate place," "Lack of motivation," "Activity intolerance," "Lack of sports ability," "Having a partner," "Using public transportation," "Perception of physical disability," "Pain," "Having a job/studying," "Laziness," "Impaired mobility," "Living in an urban area," "Education in a public institution," "Female gender," "Lack of confidence to practice physical exercise," "Education level," "Age" and "Lack of social support for the practice of physical exercise." CONCLUSION: Four out of eight clinical indicators had a good adjustment by the latent class analysis. Of the 27 aetiological factors, 22 were significantly associated with sedentary lifestyle. RELEVANCE TO PRACTICE: The correct identification of sedentary lifestyle and its elements supports care planning, especially for health promotion and disease prevention.