Łukasz Chojnowski, Mariusz Suchcicki, Karol Krupiniewicz, Miłosz Rogiński, Marek Wojciechowicz, Stanisław Rogiński, Katarzyna Mazurek, Anna Dominiczak, Marta Brzęcka and Krzysztof Rogiński 2026. THE "FITNESS AGE" CONSTRUCT IN CONSUMER WEARABLES: A CRITICAL REVIEW OF PHYSIOLOGICAL VALIDITY AND THE PSYCHOSOCIAL IMPACT ON CARDIOVASCULAR PATIENT IDENTITY. International Journal of Innovative Technologies in Social Science. 1(49) (Feb. 2026). DOI:https://doi.org/10.31435/ijitss.1(49).2026.4954.