FYSS (Fysisk aktivitet i sjukdomsprevention och sjukdomsbehandling) is an evidence-based resource dedicated to promoting physical activity for health professionals. Established in 1998 by the Association of Physical Activity (YFA), working within the Swedish Association for Physical Activity and Sports Medicine (SFAIM), FYSS provides comprehensive guidelines and recommendations for incorporating physical activity into disease prevention and treatment strategies.

Their flagship publication, the FYSS handbook, is designed for healthcare practitioners and serves as a foundational text for integrating physical activity into patient care. The latest edition, FYSS 2021, is available for purchase and offers practical insights tailored to various populations, including children, adults, and pregnant women. In addition, FYSS has developed digital tools such as eFYSS to enhance accessibility and application of its guidelines. The organization also promotes the FYSS-short version, created as part of the EU's EUPAP project, supporting the implementation of physical activity prescriptions in healthcare settings across Europe.