While spending time in a sauna can make you sweat and temporarily increase heart rate, it does not directly lead to fat loss. The weight loss you may experience after a sauna session is primarily due to fluid loss through sweating, not fat loss. This weight is quickly regained once you rehydrate.
Saunas can, however, provide benefits such as relaxation, improved circulation, and muscle recovery. While they may contribute to a feeling of well-being or help with temporary water weight loss, sustained fat loss requires a combination of regular exercise, a balanced diet, and a healthy lifestyle.