What would happen if human blood becomes acidic (low pH) ?

When human blood becomes acidic (low pH), the oxygen-carrying capacity of haemoglobin is decreased. This physiological phenomenon is known as the Bohr effect [3]. In an acidic environment, there is an increase in hydrogen ion (H+) concentration, which leads to a conformational change in the haemoglobin protein [1]. Specifically, protons associate with amino acids in haemoglobin, shifting it from a high-affinity 'relaxed' (R) form to a low-affinity 'taut' (T) form [1]. This shift reduces the affinity of haemoglobin's binding sites for oxygen, causing the oxygen-haemoglobin dissociation curve to shift to the right [2]. Consequently, haemoglobin releases its oxygen load more readily and requires a higher partial pressure of oxygen to achieve the same level of saturation [2]. While haemoglobin is the primary respiratory pigment in red blood corpuscles [1], the immediate effect of acidosis is on binding affinity rather than RBC count.

Sources

1. [1] https://www.ncbi.nlm.nih.gov/books/NBK526028/
2. [3] https://en.wikipedia.org/wiki/Bohr_effect
3. [2] https://www.sciencedirect.com/topics/medicine-and-dentistry/bohr-effect