Effects of acupuncture and heating on blood volume and oxygen saturation of human Achilles tendon in vivo

The purpose of this study was to investigate the effects of acupuncture (dry needling) and heating (application of hot pack) treatments on the blood volume and oxygen saturation of the human Achilles tendon in vivo. Nine healthy males participated in this study. During the treatments (acupuncture and heating; both 10 min) and recovery period (30 min), the blood volume and oxygen saturation of the Achilles tendon were measured using red laser lights. During needle insertion, the blood volume and oxygen saturation of the tendon increased significantly from the pre-treatment level and these values remained high throughout the 30-min recovery period. During heating treatment, the blood volume and oxygen saturation of the tendon also increased significantly. Although the increased blood volume was not maintained after removal of the hot pack, the oxygen saturation remained significantly elevated throughout the 30-min recovery period. These results suggested that acupuncture and heating treatments enhanced the blood flow in the tendon. The long-lasting increase, especially with acupuncture treatment, in the blood supply to the tendon implies that these treatments may have therapeutic effects on injured tendons.