By Carrie Perles
Updated Mar 24, 2022
A pH buffer is a carefully balanced solution that resists changes in acidity or basicity when small amounts of an acid or base are introduced. By neutralizing excess hydrogen or hydroxide ions, it keeps a solution’s pH steady, making acids less acidic and bases less basic.
When an acid enters a buffered solution, buffer molecules capture free hydrogen ions (H⁺). Because H⁺ ions are what give a solution its acidic character, removing them reduces the overall acidity.
Conversely, when a base is added, buffer molecules bind the excess hydroxide ions (OH⁻). Eliminating OH⁻ ions diminishes the solution’s basicity, maintaining the desired pH.
Exercise accelerates metabolism, generating CO₂ and hydrogen ions that accumulate as lactic acid in muscle tissue. These changes can lower blood pH. Normal blood pH is tightly regulated around 7.4; a drop below 6.8 can be fatal. Endogenous pH buffers neutralize lactic acid, preserving a healthy blood pH and ensuring proper physiological function.
