In-vivo, noninvasive measurement of muscle pH during exercise using near infrared spectroscopy

Olusola Soyemi, Michael Shear, Michelle Landry, Dulce Anunciacion, Babs Soller

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations


Muscle pH is an important indicator of inadequate blood flow and available oxygen. Muscle pH can be used to triage and help treat trauma victims and indicate poor peripheral blood flow in diabetic patients. Muscle pH can also be used to indicate exercise intensity and fatigue. We have developed methods to non-invasively measure muscle pH using Near-Infrared Spectroscopy (NIRS) and Partial Least Squares (PLS) analysis. A multi-subject PLS model correlating near infrared tissue spectra, acquired from healthy subjects during repetitive hand-grip exercise, to invasive tissue pH measurements, has been developed and validated. Subject related variations in the spectral signal; impede the development of viable multi-subject model. Within-subject variations in tissue NIR spectra often result from uncontrolled motion or blood volume changes during exercise, while subject-to-subject variations arise from differences in skin pigmentation and the fat layer thickness. We have developed signal processing techniques to account for these mitigating factors. By incorporating this signal processing techniques with PLS calibration, we can generate a pH model that has a relative standard error of prediction of 1.7%.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsB.M. Cullum, J.C. Carter
StatePublished - 2005
Externally publishedYes
EventSmart Medical and Biomedical Sensor Technology III - Boston, MA, United States
Duration: Oct 24 2005Oct 26 2005


OtherSmart Medical and Biomedical Sensor Technology III
Country/TerritoryUnited States
CityBoston, MA


  • Clinical sensor
  • Muscle pH
  • NIR spectroscopy
  • PLS Calibration

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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