title: Acute vascular effects of carbonated warm water lower leg immersion in healthy young adults.
abstract: Endothelial dysfunction is associated with increased cardiovascular mortality and morbidity; however, this dysfunction may be ameliorated by several therapies. For example, it has been reported that heat-induced increases in blood flow and shear stress enhance endothelium-mediated vasodilator function. Under these backgrounds, we expect that carbon dioxide (CO2)-rich water-induced increase in skin blood flow improves endothelium-mediated vasodilation with less heat stress. To test our hypothesis, we measured flow-mediated dilation (FMD) before and after acute immersion of the lower legs and feet in mild warm (38°C) normal or CO2-rich tap water (1000 ppm) for 20 min in 12 subjects. Acute immersion of the lower legs and feet in mild warm CO2-rich water increased FMD (P < 0.01) despite the lack of change in this parameter upon mild warm normal water immersion. In addition, FMD was positively correlated with change in skin blood flow regardless of conditions (P < 0.01), indicating that an increase in skin blood flow improves endothelial-mediated vasodilator function. Importantly, the temperature of normal tap water must reach approximately 43°C to achieve the same skin blood flow level as that obtained during mild warm CO2-rich water immersion (38°C). These findings suggest that CO2-rich water-induced large increases in skin blood flow may improve endothelial-mediated vasodilator function while causing less heat stress.
authors.affiliation: Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan ogoh@toyo.jp.
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Ogoh
authors.affiliation: School of Health Sciences Sapporo Medical University, Sapporo, Hokkaido, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Nagaoka
authors.affiliation: Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Institute of Personal Health Care Kao co ltd., Tokyo, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kimura
authors.affiliation: Institute of Personal Health Care Kao co ltd., Tokyo, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shidahara
authors.affiliation: Institute of Personal Health Care Kao co ltd., Tokyo, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Institute of Personal Health Care Kao co ltd., Tokyo, Japan.
authors.forename: Michinari
authors.initials: M
authors.lastname: Kudoh
authors.affiliation: School of Health Sciences Sapporo Medical University, Sapporo, Hokkaido, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Iwamoto
mesh_terms: D001794:Blood Pressure; D061545:Carbonated Water / Q000008:administration & dosage / Q000627:therapeutic use*; D002302:Cardiac Output; D006801:Humans; D007101:Immersion; D007866:Leg / Q000502:physiology; D008297:Male; D011897:Random Allocation; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply; D014664:Vasodilation; D055815:Young Adult
chemical_list: D061545:Carbonated Water
keywords: Brachial‐ankle pulse wave velocity; Doppler ultrasound; flow‐mediated dilation