A skin-interfaced microfluidic platform supports dynamic sweat biochemical analysis during human exercise

Area of Science:

• Biomedical Engineering
• Sports Science
• Analytical Chemistry

Background:

• Blood lactate is a key indicator of muscle acidity and athletic performance.
• Sweat offers a noninvasive alternative for physiological monitoring.
• The dynamic relationship between sweat biomarkers and blood lactate for fitness tracking is not well understood.

Purpose of the Study:

• To develop a wearable microfluidic device for real-time sweat pH and lactate measurement.
• To investigate the correlation between sweat biomarkers and blood lactate during exercise.
• To assess the potential of sweat analysis for noninvasive physiological fitness evaluation.

Main Methods:

• A microfluidic wearable band with integrated colorimetric assays was developed.
• Silver nanoplasmonic assay for lactate concentration and nanoparticle-agarose for pH analysis.
• Human participant studies involving cycling exercise and simultaneous blood lactate and sweat measurements.

Main Results:

• Sweat pH from actively working muscles decreased with increasing heart rate and correlated negatively with blood lactate.
• Sweat pH from nonworking muscles showed no correlation with blood lactate.
• Changes in sweat pH and blood lactate were observed in non-exercisers but not in regular exercisers.

Conclusions:

• Dynamic sweat pH is a potential noninvasive biomarker for monitoring exercise intensity and physiological responses.
• The findings suggest sweat analysis can be used for assessing physical fitness.
• Further development of wearable sweat sensors holds promise for continuous, noninvasive health and fitness monitoring.