What is a Buffer?
A buffer is an aqueous solution which consists of a mixture between a weak acid and its conjugate base or a mixture between a weak base and its conjugate acid. In other words, it is a substance that prevents or resists the change of pH in a system.
How does a Buffer work?
Acid to base buffers resist or prevent the change of pH in systems when hydrogen ions or hydroxide ions are either added or removed. Buffers typically consist of a weak acid and its conjugate base with high concentrations compared to the amount of protons removed which allows a subtle change, or no change in the pH of a system.
Carbonic acid Bicarbonate buffer in blood:
Why are blood buffers important?
Buffers in the blood system are important because a drastic change in the pH of blood can result in death. The optimal functioning of pH in human blood should be around 7.4. When the pH of blood becomes greater than 7.8 or less than 6.8, death can occur. Since we have a buffer in our blood, the occurrence of this is unlikely.
How does pH change in blood?
Every cell in the human body uses O2 and gives off CO2 . Blood contains H2O and can react with the CO2 that is given off by the cells to produce H2CO3, Carbonic acid. This is an acid which will react to increase the pH in the blood system but, the buffer in our blood resists the carbonic acid to keep the blood pH around 7.4. When one is exercising, their body experiences an increase in production of CO2 and H+ which causes one to breathe faster and deeper to activate the blood buffer in ones system by supplying sufficient O2 required for the increase in CO2 and H+.
Grade 12U Chemistry-Systems and Equilibrium 
I think this blog post could have used more detail. I wanted to ask – how does this topic relate to Le Chatiers principle? Also, is exercise the only way the pH can change?
Le chatelier’s principle does relate to blood buffers as when one experiences a change in temperature or pressure, they are likely to change their normal pattern of breathing which will release more CO2 and gain O2 enabling the buffer, keeping ones blood pH at normal.