[Objective]Although warm-tube moxibustion is easy-to-use in acupuncture therapy, the timing of moxa removal varies among practitioners. In the present study, we used near infrared spectroscopy (NIRS) to compare effects of different durations of moxibustion stimulation on improvement in local circulation as measured by changes in blood oxygenation dynamics in muscle tissue.
[Methods]Twelve healthy adults underwent warm-tube moxibustion with a single cone applied to the upper right shoulder region;measurements of tissue blood oxygenation dynamics (ΔOxy-Hb, ΔTotal-Hb) were obtained at intervals of 0.5 s. Control measurements were first taken for 15 min without intervention (Control);then, subjects received moxibustion 2 min after the start of measurement and had the moxa removed at the following time points: 30 s after patients experienced heat pain (Removal 30, moxibustion group); 45 s after heat pain (Removal 45, moxibustion group);or did not have the moxa removed (Continuous moxibustion group). These 4 different conditions were compared. Additionally, we determined the burning temperature of moxa and the skin temperature and intensity of heat pain sensation at the site of moxibustion.
[Results]Compared with the Control, the Removal 30, Removal 45, and Continuous moxibustion groups had significant increases in ΔOxy-Hb, ΔTotal-Hb, and skin temperature, with no significant differences among the moxibustion groups. No significant difference in the intensity of heat pain sensation was observed among the moxibustion groups. All moxibustion groups began to show rapid increases in both ΔTotal-Hb and ΔOxy-Hb around the time when subjects began to feel heat pain, suggesting that the axon reflex evoked by noxious stimuli of heat pain increased blood volume and arterial blood flow.
[Conclusion]Hemodynamic improvement in muscle tissue through the use of continuous warm-tube moxibustion for 30 s or longer after the occurrence of heat pain was confirmed.