How Breathing Affects Performance and Recovery

Title: The effect of transcutaneous application of carbon dioxide (CO2) on skeletal muscle

Authors: Oe K, Ueha T, Sakai Y, Niikura T, Lee SY, Koh A, Hasegawa T, Tanaka M, Miwa M, Kurosaka M.

Journal: Biochem Biophys Res Commun. 2011 Apr 1;407(1):148-52. doi: 10.1016/j.bbrc.2011.02.128. Epub 2011 Mar 1. PMID: 21371433.

Link to PubMed: The effect of transcutaneous application of carbon dioxide (CO2) on skeletal muscle

Abstract: In Europe, carbon dioxide therapy has been used for cardiac disease and skin problems for a long time. However there have been few reports investigating the effects of carbon dioxide therapy on skeletal muscle. Peroxisome proliferators-activated receptor (PPAR)-gamma coactivator-1 (PGC-1α) is up-regulated as a result of exercise and mediates known responses to exercise, such as mitochondrial biogenesis and muscle fiber-type switching, and neovascularization via up-regulation of vascular endothelial growth factor (VEGF). It is also known that silent mating type information regulation 2 homologs 1 (SIRT1) enhances PGC-1α-mediated muscle fiber-type switching. Previously, we demonstrated transcutaneous application of CO2 increased blood flow and a partial increase of O2 pressure in the local tissue known as the Bohr effect. In this study, we transcutaneously applied CO2 to the lower limbs of rats, and investigated the effect on the fast muscle, tibialis anterior (TA) muscle. The transcutaneous CO2 application caused: (1) the gene expression of PGC-1α, silent mating type information regulation 2 homologs 1 (SIRT1) and VEGF, and increased the number of mitochondria, as proven by real-time PCR and immunohistochemistry, (2) muscle fiber switching in the TA muscle, as proven by isolation of myosin heavy chain and ATPase staining. Our results suggest the transcutaneous application of CO2 may have therapeutic potential for muscular strength recovery resulting from disuse atrophy in post-operative patients and the elderly population.

Title: Improved exercise ventilatory efficiency with nasal compared to oral breathing in cardiac patients

Authors: Eser P, Calamai P, Kalberer A, Stuetz L, Huber S, Kaesermann D, Guler S, Wilhelm M.

Journal: Front Physiol. 2024 Aug 6;15:1380562. doi: 10.3389/fphys.2024.1380562.PMID: 39165283; PMCID: PMC11334221.

Link to full text: Improved exercise ventilatory efficiency with nasal compared to oral breathing in cardiac patients

Abstract: Objectives: To assess whether nasal breathing improves exercise ventilatory efficiency in patients with heart failure (HF) or chronic coronary syndromes (CCS). Background: Exercise inefficient ventilation predicts disease progression and mortality in patients with cardiovascular diseases. In healthy people, improved ventilatory efficiency with nasal compared to oral breathing was found. Methods: Four study groups were recruited: Patients with HF, patients with CCS, old (age≥45 years) and young (age 20-40 years) healthy control subjects. After a 3-min warm-up, measurements of 5 min with once nasal and once oral breathing were performed in randomized order at 50% peak power on cycle ergometer. Ventilation and gas exchange parameters measured with spiroergometry were analysed by Wilcoxon paired-sample tests and linear mixed models adjusted for sex, height, weight and test order. Results: Groups comprised 15 HF, CCS, and young control and 12 old control. Ventilation/carbon dioxide production (V E/V CO2), ventilation (V E), breathing frequency (fR), and end-tidal oxygen partial pressure (PETO2) were significantly lower and tidal volume and end-tidal carbon dioxide partial pressure (PETCO2) significantly higher during nasal compared to oral breathing in all groups, with large effect sizes for most parameters. For patients with HF, median V E/V CO2 was 35% lower, fR 26% lower, and PETCO2 10% higher with nasal compared to oral breathing, respectively. Exercise oscillatory ventilation (EOV) was present in 6 patients and markedly reduced with nasal breathing. Conclusion: Nasal breathing during submaximal exercise significantly improved ventilatory efficiency and abnormal breathing patterns (rapid shallow breathing and EOV) in 80% of our patients with HF and CCS.

Title: Increase in carbon dioxide accelerates the performance of endurance exercise in rats

Authors: Ueha T, Oe K, Miwa M, Hasegawa T, Koh A, Nishimoto H, Lee SY, Niikura T, Kurosaka M, Kuroda R, Sakai Y.

Journal: J Physiol Sci. 2018 Jul;68(4):463-470. doi: 10.1007/s12576-017-0548-6. Epub 2017 Jun 10. PMID: 28601950; PMCID: PMC10717130.

Link to full text: Increase in carbon dioxide accelerates the performance of endurance exercise in rats

Abstract: Endurance exercise generates CO2 via aerobic metabolism; however, its role remains unclear. Exogenous CO2 by transcutaneous delivery promotes muscle fibre-type switching to increase endurance power in skeletal muscles. Here we determined the performance of rats running in activity wheels with/without transcutaneous CO2 exposure to clarify its effect on endurance exercise and recovery from muscle fatigue. Rats were randomised to control, training and CO2 groups. Endurance exercise included activity-wheel running with/without transcutaneous CO2 delivery. Running performance was measured after exercise initiation. We also analysed changes in muscle weight and muscle fibres in the tibialis anterior muscle. Running performance improved over the treatment period in the CO2 group, with a concomitant switch in muscle fibres to slow-type. The mitochondrial DNA content and capillary density in the CO2 group increased. CO2 was beneficial for performance and muscle development during endurance exercise: it may enhance recovery from fatigue and support anabolic metabolism in skeletal muscles.

Title: Effects of an artificially carbonated bath on athletic warm-up

Authors: Akamine T, Taguchi N

Journal: J Hum Ergol (Tokyo). 1998 Dec;27(1-2):22-9. PMID: 11579696.

Link to full text: Effects of an artificially carbonated bath on athletic warm-up

Abstract: The effects of an artificially carbonated bath (36 degrees C, CO2 300 ppm, 20 minutes) on the warm-up of swimmers was compared with those of a freshwater bath (36 degrees C, 20 minutes). Carbon dioxide is reported to have a vasodilatory effect on peripheral blood vessels of cutaneous and muscular tissue and to promote blood flow. We observed that the warm-up effects of a carbonated bath before swimming on the hematocrit, white blood cell, total plasma protein, and total cholesterol levels in venous blood were significantly increased more than those of a freshwater bath before swimming in recovery period (p < 0.05). Thus the carbonated bath tended to be more effective for increasing the concentrations of blood components. In the recovery period, the carbonated bath before swimming also resulted in significantly smaller changes in blood lactic acid and heart rate than those of a freshwater bath before swimming (p < 0.05). The decrease in electromyography of the M. rectus femoris during swimming suggested more efficient muscle activity after a carbonated bath. Therefore after a carbonated bath, swimmers should have a higher reserve left in the cardiovascular system, resulting in better performance during swimming and less accumulation of fatigue-related metabolites after swimming.

Title: Enhanced Athletic Recovery Using Cold-Water Immersion with Dissolved CO2 and H2

Authors: Yoshimura M, Fukuoka Y, Sawada Y, Ichikawa H, Nakamura M

Journal: International Journal of Physical Medicine & Rehabilitation

Link to full text: Enhanced Athletic Recovery Using Cold-Water Immersion with Dissolved CO2 and H2

Abstract: A Cold therapy is widely recognized as a prescription for acute-phase recovery in athletes. However, it has been suggested that vasoconstriction caused by cooling may, in fact, delay the recovery process after exercise. Therefore, we are researching a new cooling method that involves supplementing ice baths with carbon dioxide gas, which has vasodilatory effects, and hydrogen gas, which has anti-inflammatory properties. This new approach aims to improve muscle blood flow and performance while maintaining the benefits of cooling, such as pain alleviation. This mini review provides an overview of the acute recovery effects of this innovative method and its potential applications.

Title: Repeated-sprint training in hypoxia induced by voluntary hypoventilation improves running repeated-sprint ability in rugby players.

Authors: Fornasier-Santos C, Millet GP, Woorons X.

Journal: Eur J Sport Sci. 2018 May;18(4):504-512. doi: 10.1080/17461391.2018.1431312. Epub 2018 Feb 5. PMID: 29400616.

Link to PubMed: Repeated-sprint training in hypoxia induced by voluntary hypoventilation improves running repeated-sprint ability in rugby players.

Abstract: Purpose: The goal of this study was to determine the effects of repeated-sprint training in hypoxia induced by voluntary hypoventilation at low lung volume (VHL) on running repeated-sprint ability (RSA) in team-sport players. Methods: Twenty-one highly trained rugby players performed, over a 4-week period, seven sessions of repeated 40-m sprints either with VHL (RSH-VHL, n = 11) or with normal breathing (RSN, n = 10). Before (Pre-) and after training (Post-), performance was assessed with an RSA test (40-m all-out sprints with a departure every 30 s) until task failure (85% of the reference velocity assessed in an isolated sprint). Results: The number of sprints completed during the RSA test was significantly increased after the training period in RSH-VHL (9.1 ± 2.8 vs. 14.9 ± 5.3; +64%; p < .01) but not in RSN (9.8 ± 2.8 vs. 10.4 ± 4.7; +6%; p = .74). Maximal velocity was not different between Pre- and Post- in both groups whereas the mean velocity decreased in RSN and remained unchanged in RSH-VHL. The mean SpO2 recorded over an entire training session was lower in RSH-VHL than in RSN (90.1 ± 1.4 vs. 95.5 ± 0.5%, p < .01). Conclusion: RSH-VHL appears to be an effective strategy to produce a hypoxic stress and to improve running RSA in team-sport players.

Title: Application of carbon dioxide to the skin and muscle oxygenation of human lower-limb muscle sites during cold water immersion

Authors: Yoshimura M, Hojo T, Yamamoto H, Tachibana M, Nakamura M, Tsutsumi H, Fukuoka Y.

Journal: PeerJ. 2020 Aug 21;8:e9785. doi: 10.7717/peerj.9785. PMID: 32884861; PMCID: PMC7444506.

Link to full text: Application of carbon dioxide to the skin and muscle oxygenation of human lower-limb muscle sites during cold water immersion

Abstract: Background: Cold therapy has the disadvantage of inducing vasoconstriction in arterial and venous capillaries. The effects of carbon dioxide (CO2) hot water depend mainly on not only cutaneous vasodilation but also muscle vasodilation. We examined the effects of artificial CO2 cold water immersion (CCWI) on skin oxygenation and muscle oxygenation and the immersed skin temperature. Subjects and methods: Fifteen healthy young males participated. CO2-rich water containing CO2 >1,150 ppm was prepared using a micro-bubble device. Each subject's single leg was immersed up to the knee in the CO2-rich water (20 °C) for 15 min, followed by a 20-min recovery period. As a control study, a leg of the subject was immersed in cold tap-water at 20 °C (CWI). The skin temperature at the lower leg under water immersion (Tsk-WI) and the subject's thermal sensation at the immersed and non-immersed lower legs were measured throughout the experiment. We simultaneously measured the relative changes of local muscle oxygenation/deoxygenation compared to the basal values (Δoxy[Hb+Mb], Δdeoxy[Hb+Mb], and Δtotal[Hb+Mb]) at rest, which reflected the blood flow in the muscle, and we measured the tissue O2 saturation (StO2) by near-infrared spectroscopy on two regions of the tibialis anterior (TA) and gastrocnemius (GAS) muscles. Results: Compared to the CWI results, the Δoxy[Hb+Mb] and Δtotal[Hb+Mb] in the TA muscle at CCWI were increased and continued at a steady state during the recovery period. In GAS muscle, the Δtotal[Hb+Mb] and Δdeoxy[Hb+Mb] were increased during CCWI compared to CWI. Notably, StO2values in both TA and GAS muscles were significantly increased during CCWI compared to CWI. In addition, compared to the CWI, a significant decrease in Tsk at the immersed leg after the CCWI was maintained until the end of the 20-min recovery, and the significant reduction continued. Discussion: The combination of CO2 and cold water can induce both more increased blood inflow into muscles and volume-related (total heme concentration) changes in deoxy[Hb+Mb] during the recovery period. The Tsk-WI stayed lower with the CCWI compared to the CWI, as it is associated with vasodilation by CO2.

Title: Anaerobic performance after 3-day consecutive CO2-rich cold-water immersion in physically active males

Authors: FFujita M, Yoshimura M, Nakamura M, Hojo T, Fukuoka Y.

Journal: J Exerc Sci Fit. 2022 Apr;20(2):148-154. doi: 10.1016/j.jesf.2022.02.004. Epub 2022 Mar 4. PMID: 35356104; PMCID: PMC8921317.

Link to full text: Anaerobic performance after 3-day consecutive CO2-rich cold-water immersion in physically active males

Abstract:
Background objective: We investigated the effects of a 3-day consecutive CO2-rich cold (20 °C) water immersion (CCWI) following a high-intensity intermittent test (HIIT) on subjects' sublingual temperature (Tsub), blood lactate ([La]b), and heart rate (HR) compared to cold (20 °C) tap-water immersion (CWI) or passive recovery (PAS).

Methods: Thirty-two subjects were randomly allocated into three groups (CCWI, CWI, and PAS), each of which completed 4 consecutive days of cycling experiments. HR, Tsub, and [La]b were recorded on each day of exercise testing (immersion from Day 1 to Day 3 and Day 4). HIIT consisted of 8 sets of 20-sec maximum exercise at an intensity of 120% of VO2max with 10-sec passive rest. The mean and peak power, and peak pedal repetitions (PPR) within HIIT were averaged and the decline in PPR (ΔPPR) from Day 1 to Day 4 was measured.

Results: In CCWI and CWI, HR declined significantly following each immersion, with CCWI showing the larger reduction (p < 0.001). At Day 2, CCWI showed a significantly lower [La]b compared to PAS (p < 0.01). The changes in mean and peak power from Day 1 to Day 4 did not differ among the groups (p = 0.302). ΔPPR of HIIT was significantly correlated with the HR and [La]b values after immersions (ΔPPR-HR: r2 = 0.938, p < 0.001, ΔPPR-[La]b: r2 = 0.999, p < 0.001).

Conclusions: These findings indicate that CCWI is a promising intervention for maintaining peak performance in high-intensity intermittent exercise, which is associated with a reduction in [La]b and HR.

Title: The field study about the effects of artificial CO2-rich cool-water immersion after outdoor sports activity in a hot environment

Authors: Yoshimura M, Nakamura M, Hojo T, Arai A, Fukuoka Y.

Journal: J Exerc Sci Fit. 2023 Jul;21(3):268-274. doi: 10.1016/j.jesf.2023.05.001. Epub 2023 May 10. PMID: 37250065; PMCID: PMC10209124.

Link to full text: The field study about the effects of artificial CO2-rich cool-water immersion after outdoor sports activity in a hot environment

Abstract:
Background/objective: In our previous laboratory experiment (room temperature of 25 °C), CO2-rich cool-water immersion (CCWI) suppressed subjects' core body temperature even during repeated exercise. It is unclear whether the suppression of body temperature elevation would also continue after CCWI in a hot outdoor environment. Herein we investigated the thermal effects of CCWI after regular exercise training in heat on subjects' core temperature (Tcore), three skin temperatures (Tskin), heart rate (HR), and the rate of perceived ice (RPI).

Methods: Thirty-six subjects (25 males, 11 females) were randomly allocated into three groups (CCWI, CWI, and control). After training at their competitive clubs, each subject was immersed up to the chest in CCWI or CWI at 20 °C for 20 min, followed by a 60-min recovery period. Tcore, Tskin, HR, and RPI were measured at the initial rest, the end of immersion, and every 10 min during the recovery period.

Results: Compared to the control, the CCWI subjects' Tcore was significantly lower at 50-60 min after the end of immersion (p < 0.05). Tskin at abdominal and lower-leg regions during the recovery period was maintained at significantly lower values in the CWI and CCWI groups versus control (p < 0.05). The CCWI subjects maintained lower Tskin for a longer time than the CWI subjects.

Conclusions: These findings indicate that CCWI suppresses the rise in body temperatures more than CWI, even in a hot environment, suggesting that CCWI may be a more effective countermeasure against increasing body temperature in a hot outdoor environment.

Title: Increase in carbon dioxide accelerates the performance of endurance exercise in rats

Authors: Ueha T, Oe K, Miwa M, Hasegawa T, Koh A, Nishimoto H, Lee SY, Niikura T, Kurosaka M, Kuroda R, Sakai Y.

Journal: J Physiol Sci. 2018 Jul;68(4):463-470. doi: 10.1007/s12576-017-0548-6. Epub 2017 Jun 10. PMID: 28601950; PMCID: PMC10717130.

Link to full text: Increase in carbon dioxide accelerates the performance of endurance exercise in rats

Abstract: Endurance exercise generates CO2 via aerobic metabolism; however, its role remains unclear. Exogenous CO2 by transcutaneous delivery promotes muscle fibre-type switching to increase endurance power in skeletal muscles. Here we determined the performance of rats running in activity wheels with/without transcutaneous CO2 exposure to clarify its effect on endurance exercise and recovery from muscle fatigue. Rats were randomised to control, training and CO2 groups. Endurance exercise included activity-wheel running with/without transcutaneous CO2 delivery. Running performance was measured after exercise initiation. We also analysed changes in muscle weight and muscle fibres in the tibialis anterior muscle. Running performance improved over the treatment period in the CO2 group, with a concomitant switch in muscle fibres to slow-type. The mitochondrial DNA content and capillary density in the CO2 group increased. CO2 was beneficial for performance and muscle development during endurance exercise: it may enhance recovery from fatigue and support anabolic metabolism in skeletal muscles.

Keywords: Activity wheel; Carbon dioxide; Endurance exercise; Running performance.

Title: Inspired carbon dioxide during hypoxia: effects on task performance and cerebral oxygen saturation

Authors: Van Dorp E, Los M, Dirven P, Sarton E, Valk P, Teppema L, Stienstra R, Dahan A.

Journal: Aviat Space Environ Med. 2007 Jul;78(7):666-72. PMID: 17679563.

Link to PubMed: Inspired carbon dioxide during hypoxia: effects on task performance and cerebral oxygen saturation

Abstract: Introduction: Exposure to a hypoxic environment has a deleterious effect on physiological and mental functions. We studied the effect of added inspired CO2 during artificially induced hypoxic normobaric hypoxia (oxygen saturation approximately 80%) on complex task performance.

Methods: In random order, 22 healthy volunteers were exposed to 3 gas mixtures for 50 min each: sham hypoxia (SH, PetO2 103 mmHg without inspired CO2); isocapnic hypoxia (IH, PetO2 approximately 40 mmHg, PetcO2 clamped to 0.4 mmHg above resting values); and poikilocapnic hypoxia (PH, PetO2 approximately 40 mmHg; no inspired CO2). Brain oxygenation was measured using near infrared spectroscopy. During minutes 25-45 of hypoxia, subjects performed vigilance and task performance tests used in aviation research: the Vigilance and Tracking test and the Multi-Attribute Task battery (MAT-bat). The tests varied in difficulty with the tracking tests considered most difficult.

Results: PetCO2 levels differed significantly among groups: IH 42.8 +/- 0.7, SH 39.0 +/- 0.7, and PH 36.8 +/- 0.7 mmHg. Brain oxygenation levels were significantly higher during IH than PH (62.2 +/- 1.0 vs. 59.1 +/- 1.3%). The results of the performance tests indicated a negative effect of PH vs. SH on most function tests. For the Tracking test of the MAT-bat, performance was worst during PH, but returned to baseline during IH.

Discussion: We demonstrate the ability of added inspired CO2 to improve performance during hypoxia by preventing PH-associated hypocapnia-induced vasoconstriction of brain blood vessels. Our results are relevant to aerospace medicine and other circumstances in which complex tasks are performed in a hypoxic environment such as mountain climbing and working in confined spaces.