The Human Breath Volatilome Responds to Exercise and Recovery: An Untargeted Profiling Study

Exercise induces metabolic and physiological changes across multiple organs. These changes have been studied via several human biofluids, including urine and blood; however, they remain mainly underexplored in exhaled breath. In this exploratory pilot study, we performed untargeted profiling of breath volatile compounds (VCs) to investigate how exercise and recovery influence breath chemical composition. Breath samples were collected from 71 university athletes from three sporting disciplines. Across 143 breath samples, a total of 1,204 unique breath VCs were detected. There were distinct volatilomic responses to physical activity and recovery, regardless of the athlete's sport. Comparison of paired samples using volcano analysis collected before and during exercise identified 80 breath VCs that significantly increased and 182 that significantly decreased. Similarly, a comparison of samples collected before and after exercise identified 11 compounds that decreased significantly. These findings demonstrate that exercise induces measurable changes in the breath volatilome. However, due to the lack of standardized exercise intensity measures and physiological monitoring, the results should be considered exploratory and interpreted cautiously within the field of exercise science.