Regional Difference of Muscle Oxygen Saturation and Blood Volume during Exercise Determined by Near Infrared Imaging Device.

Abstract

During exercise, the metabolic need for oxygen in muscles increases many times above the resting level. To meet this oxygen demand, oxygen supply to the contracting muscle must increase; this is accomplished by an increased cardiac output and a redistribution of the blood supply. During exercise, heteroJapanese Journal of Physiology Vol. 51, No. 5, 2001 599Japanese Journal of Physiology, 51, 599-606, 2001 Key words: near infrared light, imaging, oxygen saturation, blood volume, heterogeneity.Abstract: Using a near infrared (NIR) imaging device, we tested the hypothesis that regional differences in oxygen status could be detected in the gastrocnemius muscle during exercise and recovery. Six healthy subjects performed the standing plantar flexion exercises for 2 min; the frequency was one contraction per second. The NIR imaging device was placed over the medial head of the right gastrocnemius muscle and the signals from two optical sensors situated on the middle proximal and middle distal portions were used. The NIR-O 2 saturation (difference between deoxygenated and oxygenated Hb signals) and NIR-blood volume (sum of the oxygenated and deoxygenated Hb signals) were calculated in optical density units. Plantar flexion resulted in more deoxygenation during exercise and more reoxygenation during recovery in the distal portion compared with the proximal portion. The changes in NIR-O 2 between rest and a 2 min exercise, and between a 2 min exercise and a 3 min recovery were 0.11 and Ϫ0.23, respectively, in the distal portion, which were significantly larger than proximal values (0.05 and Ϫ0.10, pϽ0.05). Plantar flexion resulted in lower NIR-blood volumes during exercise and greater recovery of blood after exercise in the distal portion compared with the proximal portion. The changes in NIR blood volume between rest and a 2 min exercise and between a 2 min exercise and a 3 min recovery were Ϫ0.19 and 0.31, respectively, in the distal portion, significantly larger than proximal values (Ϫ0.07 and 0.12, pϽ0.05 for all comparisons). These findings indicate that the distal portion of the medial gastrocnemius had larger changes in NIR-O 2 saturation and NIR-blood volume than the proximal portion had. This is consistent with the distal portion having a greater impairment of blood flow possibly because of the higher intramuscular pressure during exercise. In conclusion: (1) regional differences in oxygen status in the gastrocnemius muscle were detected with exercise, with the distal portion having greater NIR-O 2 saturation and NIR-blood volume changes, and (2) the NIR imaging device might be a useful method to detect the regional differences of oxygen status in the muscle.

Muscle Architecture and its Relationship to Muscle Circulation

“…Miura, et al, (2001) showed that the distal portion of the medial gastrocnemius had larger changes in muscle oxygen saturation and blood volume (measured using NIRS) than the proximal portion had. To elucidate the relationship between muscle architecture and muscle circulation heterogeneity within the same muscles, Miura, et al, (2004) measured architectural properties, oxygen supply, and consumption index in the medial head of the gastrocnemius muscle in vivo using B-mode ultrasound and functional near infrared (NIR) imaging devices.…”

“…The finding that muscle architecture differed among different sites of the same muscle (Maganaris, et al, 1998, Muramatsu, et al, 2002a will lead to the heterogeneity of muscle circulation or metabolism (Miura, et al, 2001). Miura, et al, (2001) showed that the distal portion of the medial gastrocnemius had larger changes in muscle oxygen saturation and blood volume (measured using NIRS) than the proximal portion had.…”

Methodological validation of the dynamic heterogeneity of muscle deoxygenation within the quadriceps during cycle exercise

“…The CW-NIRS used in previous studies enabled identification of regional differences in blood volume and deoxygenation in muscle during exercise (22,25,30,39,43). However, assumptions of constant path length, absorption, and scattering coefficients used to convert the CW-NIRS signal to the relative concentration values limit the accuracy of measurement and may overestimate the changes in NIRS variables during exercise (15).…”

Functional Imaging of Human Skeletal Muscle During Movement: Implications for Recruitment, Metabolism and Circulation

“…The advantage of this technique is that it is noninvasive, relatively inexpensive, easy to use, and portable. Very limited reports regarding NIRS imaging in exercising skeletal muscle have been published (Miura, et al, 2003, Miura, et al, 2001, Miura, et al, 2004, Quaresima, et al, 2001). Quaresima, et al (2001) reported that no significant difference in muscle oxygenation and blood volume change in the 12 measurement sites over a surface of 8 x 8 cm 2 of the thigh (rectus femoris and vastus lateralis was measured) during intermittent and continuous maximum voluntary contraction.…”

“…Quaresima, et al (2001) reported that no significant difference in muscle oxygenation and blood volume change in the 12 measurement sites over a surface of 8 x 8 cm 2 of the thigh (rectus femoris and vastus lateralis was measured) during intermittent and continuous maximum voluntary contraction. On the contrary, Miura, et al (2001) http://www.soc.nii.ac.jp/jspe3/index.htm 203 regional difference in oxygenation and blood volume, with the distal region being higher than that of the proximal in the medial gastrocnemius muscle during dynamic calf-raising exercise (Figure 7). They demonstrated, in another study, that the regional difference of oxygenation and blood volume was highly related to architecture (fascicle length and angle) in exercising medial gastrocnemius muscle (Miura, et al, 2004).…”