[OPTICAL REVIEW Vol. 10, No. 5 (2003) 493-497]
© 2003 The Optical Society of Japan

Quantitative Evaluation of Oxygenation and Metabolism in the Human Skeletal Muscle

Takafumi HAMAOKA1,2,*, Takuya OSADA1, Norio MURASE1, Takayuki SAKO3, Hiroyuki HIGUCHI1, Yuko KUROSAWA1, Mitsuharu MIWA4, Toshihito KATSUMURA1 and Britton CHANCE5

1Department of Preventive Medicine and Public Health, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, Japan
2National Institute of Fitness and Sports, 1 Shiromizu-cho, Kanoya, Kagoshima, Japan
3Exercise Physiology, Department of Food & Nutrition, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo, Japan
4Hamamatsu Photonics, 5000 Hiraguchi, Hamakita City, Shizuoka Prefecture, Japan
5Department of Biochemistry and Biophysics, University of Pennsylvania, D501 Richards Building, Philadelphia, USA

(Received March 10, 2003; Accepted April 22, 2003)

The forearm muscles of five healthy males were monitored for changes in microvessel hemoglobin saturation (SO2-TRS) by near infrared time-resolved spectroscopy (NIRTRS) and changes in phosphorus metabolites by magnetic resonance spectroscopy (31P-MRS) during 12 min of resting arterial occlusion. Muscle oxygenation and phosphorus metabolites were also measured during grip exercises at varying intensities. Upon the initiation of occlusion, SO2-TRS fell progressively until it reached a plateau in the latter half of the occlusion. Phosphocreatine (PCr) began to decrease around 6 min after the initiation of arterial occlusion. The resting O2 store and O2 consumption were 295 μM and 0.95 μM/sec, respectively-values which reasonably agree with the reported results. A significant correlation was observed between the changes in SO2-TRS and PCr during exercise (r2 = 0.80, p < 0.001). These results indicate that NIRTRS is able to provide reliable information about resting metabolism and oxidative rate during exercise. NIRTRS and MRS are useful to monitor oxygenation and energetics noninvasively in the human muscle.

Key words: muscle oxygenation; O2 gradient; basal O2 consumption; phosphocreatine (PCr); near infrared

*E-mail address: kyp02504@nifty.ne.jp