CHARACTERISTICS OF ACID-BASE BALANCE CHANGES IN BLOOD DURING MUSCLE ACTIVITY AND THEIR INFLUENCE ON RESPIRATORY GAS DYNAMICS
Abstract
The objective of this study is to examine the impact of alterations in blood acid–base balance components during muscular activity on the dynamics of respiratory gases. During physical exertion, accelerated transport and diffusion processes occur in the body. However, they may not always adequately supply O2 to the mitochondria of skeletal muscles under heightened functional demand. Consequently, accumulation of incompletely oxidized metabolic products occurs within these muscles, resulting in the release of lactate into the blood, where it dissociates to form lactate ions (salts of lactic acid). These processes lead to changes in the acid-base balance of blood (ABB), significantly influencing the dynamics of respiratory gases in the body. This article describes the impact of ABB changes on the processes that facilitate the necessary conditions for oxygen transport and diffusion to working muscles. Additionally, an analysis is conducted on the role of blood buffering properties in regulating ABB. Research on arterial blood ABB parameters indicates that the redistribution of buffering bases varies depending on the intensity of the workload: during high-intensity exercises (60% VO2max), it is not yet distinctly expressed; at submaximal intensity (85% VO2max), venous hypercapnia reaches critical levels with PCO2 in some athletes reaching 75-80 mmHg, sharply increasing the deficit of buffering bases. At VO2max, alongside significant oxygen debt, a high excess of CO2 excretion is observed, with total quantities exceeding 10 liters, of which 75% occur during recovery periods. pH levels can drop to 7.11, with a notable decrease in buffering bases and available bicarbonate. The VЕ from 0.74 at rest increases to -16.2 mEq/L, accompanied by reduced quantities of buffering bases and available bicarbonate. Thus, interrelated processes of ABB components and characteristics of respiratory gas dynamics during muscle activity are analyzed, which may hold both theoretical and practical significance for identifying crucial components of organism functional reserves.
References
2. Artioli, G. G., Gualano, B., Smith, A., Stout, J., & Lancha, A. H., Jr. (2010). Role of beta-alanine supplementation on muscle carnosine and exercise performance. Medicine & Science in Sports & Exercise, 42(6), 1162–1173. https://doi.org/10.1249/MSS.0b013e3181c74e38
3. Astrup, P., & Severinghaus, J. W. (1985). The history of blood gases, acids and bases. Munksgaard.
4. Böning, D., & Maassen, N. (2018). Relation between lactic acid and base excess during muscular exercise. European Journal of Applied Physiology, 118(4), 863–864. https://doi.org/10.1007/s00421-018-3824-0
5. Coqueiro, A. Y., Rogero, M. M., & Tirapegui, J. (2019). Glutamine as an anti-fatigue amino acid in sports nutrition. Nutrients, 11(4), 863. https://doi.org/10.3390/nu11040863
6. Kamel, K. S., Oh, M. S., & Halperin, M. L. (2020). L-lactic acidosis: Pathophysiology, classification, and causes; emphasis on biochemical and metabolic basis. Kidney International, 97(1), 75–88. https://doi.org/10.1016/j.kint.2019.08.023
7. Kaufman, D. P., Kandle, P. F., Murray, I. V., & Dhamoon, A. S. (2023). Physiology, oxyhemoglobin dissociation curve. In StatPearls [Internet]. StatPearls Publishing.
8. Kemp, G., Böning, D., Beneke, R., & Maassen, N. (2006). Explaining pH change in exercising muscle: Lactic acid, proton consumption, and buffering vs. strong ion difference. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, 291(1), R235–R239. https://doi.org/10.1152/ajpregu.00662.2005
9. Klausen, K. (1965). Comparison of CO₂ rebreathing and acetylene methods for cardiac output. Journal of Applied Physiology, 20, 763–766. https://doi.org/10.1152/jappl.1965.20.4.763
10. Kraut, J. A., & Madias, N. E. (2010). Metabolic acidosis: Pathophysiology, diagnosis and management. Nature Reviews Nephrology, 6(5), 274–285. https://doi.org/10.1038/nrneph.2010.33
11. Lim, S. (2007). Metabolic acidosis. Acta Medica Indonesiana, 39(3), 145–150.
12. Melkonian, E. A., & Schury, M. P. (2023). Biochemistry, anaerobic glycolysis. In StatPearls [Internet]. StatPearls Publishing.
13. Navaneethan, S. D., Jun, S., Buysse, J., & Bushinsky, D. A. (2019). Effects of treatment of metabolic acidosis in CKD: A systematic review and meta-analysis. Clinical Journal of the American Society of Nephrology, 14(7), 1011–1020. https://doi.org/10.2215/CJN.13091118
14. Nelson, M. T., Biltz, G. R., & Dengel, D. R. (2015). Repeatability of respiratory exchange ratio time series analysis. Journal of Strength and Conditioning Research, 29(9), 2550–2558. https://doi.org/10.1519/JSC.0000000000000924
15. Poole, D. C., Rossiter, H. B., Brooks, G. A., & Gladden, L. B. (2021). The anaerobic threshold: 50+ years of controversy. The Journal of Physiology, 599(3), 737–767. https://doi.org/10.1113/JP279963
16. Robergs, R. A., Ghiasvand, F., & Parker, D. (2004). Biochemistry of exercise-induced metabolic acidosis. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, 287(3), R502–R516. https://doi.org/10.1152/ajpregu.00114.2004
17. Siggaard-Andersen, O. (1960). A graphic representation of changes of the acid-base status. Scandinavian Journal of Clinical and Laboratory Investigation, 12(3), 311–314. https://doi.org/10.3109/00365516009062441
18. Siggaard-Andersen, O. (1974). The acid-base studies of the blood. Munksgaard.
19. Street, D., Bangsbo, J., & Juel, C. (2001). Interstitial pH in human skeletal muscle during and after dynamic graded exercise. The Journal of Physiology, 537(Pt 3), 993–998. https://doi.org/10.1111/j.1469-7793.2001.00993.x
20. Turhan, S., Tutan, D., & Şahiner, Y. (2023). Exploring the feasibility of calculating expected pCO₂ from venous blood gas samples alone in intensive care patients. Cureus, 15(8), e42944. https://doi.org/10.7759/cureus.42944