The rapid advancement of personalized healthcare brings forth a myriad of self-powered integrated sweat fabric systems. However, challenges such as alkaline by-products, low open-circuit voltage and output power have made them unsuitable for the continuously powering biosensors. Here, we have designed a sweat-activated polyaniline/single-wall carbon nanotube||Zinc (PANI/SWCNTs||Zn) battery fabric featuring multiple redox states. This innovative battery achieves a high open-circuit voltage of 1.2 V within 1.0 s and boasts an impressive power density of 2.5 mW cm-2 due to the rapid solid–liquid two-phase electronic/ionic transfer interface. In-depth characterization reveals that the discharge mechanism involves the reduction of emeraldine salt to leucoemeraldine without oxygen reduction. By integrating this system seamlessly, the sweat-activated batteries can directly power a patterned light-emitting diode and a multiplexed sweat biosensor, while wirelessly transmitting data to a user interface via Bluetooth. This strategic design offers safety warnings and continuous real-time health monitoring for night walking or running. This work paves the way for the development of an efficient and sustainable energy-autonomous electronic fabric system tailored for individual health monitoring. Highly power-density sweat-activated PANI/SWCNTs||Zn fiber battery has been fabricated by rapid reduction of emeraldine salt to leucoemeraldine. Through seamless system integration, the thus-fabricated sweat-activated battery pack can power a multiplexed sweat biosensor, demonstrating the feasibility of a sustainable energy-autonomous electronic fabric system for continuous individual health monitoring.