Human respiration is accompanied with abundant physiological and pathological information, such as the change in ammonia (NH 3 ) content, which is related to chronic kidney disease (CKD); hence, monitoring the breathing behavior helps in health assessment and illness prediction. In this work, a wearable respiration sensor based on CeO 2 @polyaniline (CeO 2 @PANI) nanocomposites that underwent a hydrogen plasma treatment is developed. The results unambiguously show that the response of the corresponding nanocomposites is significantly enhanced from 165 to 670% to 100 ppm NH 3 compared to the counterpart that did not undergo hydrogen plasma treatment and even reaches 24% to 50 ppb NH 3 , suggesting its fascinating capability of detecting the trace level of NH 3 in human breathing. The superior response for NH 3 is ascribed to the stable oxygen vacancies produced by the hydrogen plasma treatment. Furthermore, the clinical tests for patients with uremia suggest that the as-designed sensor has potential applications in clinical monitoring for CKD. Herein, this work offers a new strategy to obtain respiration sensors with high performance and provides a feasible approach for health evaluation and disease monitoring of patients with CKD.