Evaluating the Feasibility of Breath-Based Lactate Monitoring : A Lightweight Mask Integrating CO₂ and Acetone Sensors

Sammanfattning

Invasive blood sampling and costly metabolic carts are the golden standard but impractical methods for tracking blood lactate levels during exercise, an important marker for performance and fatigue. This project explores a simpler, more affordable alternative which is a portable mask equipped with off-the-shelf CO₂ and total volatile organic compound (tVOC) sensors to estimate lactate-like metabolic changes in real time. By comparing exhaled breath data across different exercise intensities, the research examines whether trends in CO₂ and acetone (the primary component of tVOCs in breath) parallel rises or falls in blood lactate and workload. Results show that while raw sensor data were influenced by factors such as breath frequency and sensor lag, an algorithmic correction to reduce the effect of varying breath frequency for CO₂ readings revealed patterns that broadly follow changes in exercise workload. Acetone readings, measured via a generic tVOC sensor, exhibited more noise and sensor contamination but still indicated potential shifts in metabolism. Although the correlation between breath-derived measures and blood lactate was moderate, partly because of limited blood lactate sampling and multi-session design, the study demonstrates the feasibility of using two low-cost sensors to gain metabolic insights. This innovation could lower barriers for sports teams, fitness enthusiasts, and clinical contexts, offering a stepping stone toward real-time, non-invasive monitoring of anaerobic metabolism and training thresholds.