Scientific Research on CO2 Therapy and Breathing

Scientific Research on CO2 Therapy and Breathing

Blood Pressure, Heart Rate, Circulation, Wound Healing, Diabetes Foot

Title: Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Authors: Ogoh S, Washio T, Suzuki K, Ikeda K, Hori T, Olesen ND, Muraoka Y.

Journal: Physiol Rep. 2018 Sep;6(18):e13859. doi: 10.14814/phy2.13859. PMID: 30221833; PMCID: PMC6139710.

Link to full text: Effect of leg immersion in mild warm carbonated water on skin and muscle blood flow

Abstract: Leg immersion in carbonated water improves endothelial-mediated vasodilator function and decreases arterial stiffness but the mechanism underlying this effect remains poorly defined. We hypothesized that carbonated water immersion increases muscle blood flow. To test this hypothesis, 10 men (age 21 ± 0 years; mean ± SD) underwent lower leg immersion in tap or carbonated water at 38°C. We evaluated gastrocnemius muscle oxyhemoglobin concentration and tissue oxygenation index using near-infrared spectroscopy, skin blood flow by laser Doppler flowmetry, and popliteal artery (PA) blood flow by duplex ultrasound. Immersion in carbonated, but not tap water elevated PA (from 38 ± 14 to 83 ± 31 mL/min; P < 0.001) and skin blood flow (by 779 ± 312%, P < 0.001). In contrast, lower leg immersion elevated oxyhemoglobin concentration and tissue oxygenation index with no effect of carbonation (P = 0.529 and P = 0.495). In addition, the change in PA blood flow in response to immersion in carbonated water correlated with those of skin blood flow (P = 0.005) but not oxyhemoglobin concentration (P = 0.765) and tissue oxygenation index (P = 0.136) while no relations was found for tap water immersion. These findings indicate that water carbonation has minimal effect on muscle blood flow. Furthermore, PA blood flow increases in response to lower leg immersion in carbonated water likely due to a large increase in skin blood flow.

Title: Carbonate Ion-Enriched Hot Spring Water Promotes Skin Wound Healing in Nude Rats

Authors: Liang J, Kang D, Wang Y, Yu Y, Fan J, Takashi E.

Journal: PLoS One. 2015 Feb 11;10(2):e0117106. doi: 10.1371/journal.pone.0117106. PMID: 25671581; PMCID: PMC4324962.

Link to full text: Carbonate Ion-Enriched Hot Spring Water Promotes Skin Wound Healing in Nude Rats

Abstract: Hot spring or hot spa bathing (Onsen) is a traditional therapy for the treatment of certain ailments. There is a common belief that hot spring bathing has therapeutic effects for wound healing, yet the underlying molecular mechanisms remain unclear. To examine this hypothesis, we investigated the effects of Nagano hot spring water (rich in carbonate ion, 42°C) on the healing process of the skin using a nude rat skin wound model. We found that hot spring bathing led to an enhanced healing speed compared to both the unbathed and hot-water (42°C) control groups. Histologically, the hot spring water group showed increased vessel density and reduced inflammatory cells in the granulation tissue of the wound area. Real-time RT-PCR analysis along with zymography revealed that the wound area of the hot spring water group exhibited a higher expression of matrix metalloproteinases-2 and -9 compared to the two other control groups. Furthermore, we found that the enhanced wound healing process induced by the carbonate ion-enriched hot spring water was mediated by thermal insulation and moisture maintenance. Our results provide the evidence that carbonate ion-enriched hot spring water is beneficial for the treatment of skin wounds.

Title: A Novel Bathing Therapeutic Approach for Diabetic Foot Ulcers

Authors: Tappia PS, Hiebert B, Sanjanwala R, Komenda P, Sathianathan C, Arneja AS, Ramjiawan B.

Journal: Applied Sciences. 2021; 11(18):8402. https://doi.org/10.3390/app11188402

Link to full text: A Novel Bathing Therapeutic Approach for Diabetic Foot Ulcers

Abstract: Ineffective healing and treatment of foot ulcers can lead to an infection and gangrene of the wound area that ultimately results in the loss of the limb. The incidence of foot ulcers is higher in patients with diabetes, peripheral vascular disease and kidney disease. Accordingly, this study was undertaken to assess the ability of foot bathing in CO2-enriched water to heal foot ulcers. The design was a double-blinded, randomized, placebo-controlled study. Patients with at least one foot ulcer were randomized to receive either a treatment with bath therapy at 37 ± 0.5 °C containing either 1000–1200 ppm CO2-enriched tap water (the intervention) or non-carbonated tap water at 37 ± 0.5 °C (the control group). Treatment was conducted three times/week for 15 min per session for up to 16 weeks for a total of 48 treatment sessions. Before and at the end of every treatment month, wound size, wound area oxygenation and the ankle brachial index were measured. In addition, the McGill pain questionnaire was conducted. Blood was also collected at these time points (for a total of five collections) for the measurement of different biomarkers. While no significant differences (p < 0.05) in the group/time interaction effect were observed, a clear separation within the wound area reduction/wound area/oxygenated Hb outcomes was seen between placebo (control) and treatment (CO2) group. This pilot study is suggestive that bathing in CO2-enriched water may accelerate the healing of foot ulcers.

Title: Effect of Carbon Dioxide Therapy on Diabetic Foot Ulcer

Authors: Shalan, N. , Al-Bazzaz, A. , Al-Ani, I. , Najem, F. and Al-Masri, M.

Journal: Journal of Diabetes Mellitus, 5, 284-289. doi: 10.4236/jdm.2015.54035.

Link to full text: Effect of Carbon Dioxide Therapy on Diabetic Foot Ulcer

Abstract: Ulceration of diabetic foot represents one of the most concerning complications associated with uncontrolled blood sugar in diabetes mellitus. The aim of this study is to evaluate the condition of twenty-two diabetic patients with different degrees of ulceration in their feet after daily secessions of carbon dioxide therapy. Blood flow to the affected foot was measured by Doppler; also the size, color, degree of ulceration and sensation of the ulcerative area were all evaluated. Results showed improvement of blood flow to the affected foot as well as improvement in the sensation and color of the ulcerative area. It was concluded that carbon dioxide therapy of diabetic foot was promising and needed thorough investigation to be brought widely into application.

Title: Cognitive factors in carbon dioxide therapy

Authors: van den Hout MA, Griez E.

Journal: J Psychosom Res. 1982;26(2):209-14. doi: 10.1016/0022-3999(82)90038-1. PMID: 6804625.

Link to PubMed: Cognitive factors in carbon dioxide therapy

Abstract: The effects of CO2 inhalation on subjective state, heart rate and blood pressure were studied in two differently instructed groups, with use of air for placebo. Participants who were told that inhalation would produce a state of pleasant relaxation reported a statistically significant, confirming change when administered CO2, whereas air was found not to alter the subjective state appreciably. Those who had expected unpleasant feelings of tension did show a non-significant change in this respect after CO2 inhalation and no such reaction at all to the placebo. Heart rate and diastolic blood pressure dropped significantly after CO2 intake. Surprisingly, participants were subject to a significant decrease in heart rate upon inhalation of air when relaxation was expected. Finally, a number of theoretical inferences are made and the role of cognitive processes in the clinical use of CO2 therapy is underscored.

Title: Cardiovascular and subjective responses to inhalation of carbon dioxide. A controlled test with anxious patients

Authors: van den Hout MA, Griez E.

Journal: Psychother Psychosom. 1982;37(2):75-82. doi: 10.1159/000287556. PMID: 6812154.

Link to PubMed: Cardiovascular and subjective responses to inhalation of carbon dioxide. A controlled test with anxious patients

Abstract: Cardiovascular and subjective responses to inhalation of a 35% CO2 mixture were studied in a sample of anxious neurotics. Inhalation of air was used as a placebo control treatment. In comparison with the inhalation of air, CO2 produced a significant drop in diastolic blood pressure. A drop in heart rate frequency was observed both after inhalation of CO2 and air. CO2 inhalation did not produce an average decline in subjective feelings of distress. Explanations of these data are offered and they are compared with earlier findings. Some speculations are made on the clinical usefulness of CO2 inhalation in the treatment of anxious neurotics.