From the Guidelines
The normal pH range of blood in humans is between 7.35 and 7.45 units. This narrow range is critical for proper functioning of enzymes, proteins, and cellular processes throughout the body [ 1 ]. The body maintains this precise pH through several buffer systems, primarily the bicarbonate buffer system, which can quickly neutralize acids or bases that enter the bloodstream. Key factors that help regulate blood pH include:
- The lungs, which control carbon dioxide levels through respiration
- The kidneys, which provide longer-term pH regulation by excreting or retaining hydrogen ions and bicarbonate If blood pH falls below 7.35, a condition called acidosis occurs, while a pH above 7.45 results in alkalosis - both of which can cause serious health problems if not corrected [ 1 ]. The body's remarkable ability to maintain blood pH within such tight constraints is essential for survival, as even small deviations can significantly impact oxygen delivery to tissues and overall cellular function. Acidosis is defined as a pH<7.35, and alkalosis is defined as a pH>7.45, with acidity in any fluid determined by the concentration of hydrogen ions [H+], normally regulated between 35 and 45 nmol/L [ 1 ].
From the Research
Blood pH Levels
- The normal pH level of human blood is slightly alkaline, with a value of around 7.4 2.
- This slightly alkaline pH is essential for cell metabolism, normal physiology, and balanced immunity, as all biological processes are pH-dependent 3.
- The blood pH range is typically considered to be between 7.35 and 7.45 4.
Acid-Base Balance
- Varieties of physiologic derangements can occur when the blood pH is disrupted, and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) proliferates in acidic blood 3.
- Blood acidemia is linked to increased morbidity and mortality due to its complications on immunity, especially in the elderly and in critical diseases such as cancer, musculoskeletal degradation, renal, cardiac, and pulmonary disorders 3.
- Correcting the acid-base balance might be a crucial strategy for the treatment of COVID-19, which could be attributed to the distraction of the viral spike protein to its cognate receptor angiotensin-converting enzyme 2 and supporting the over-taxed immunity 3.
pH Regulation
- The alpha-stat theory of acid-base management interprets the normal value of arterial pH as a value derived from the intracellular pH, which is close to neutrality 2.
- The interstitial fluid pH is unstable compared to the arterial blood pH, even when the arterial blood pH stays within the normal range 4.
- Changes in interstitial fluid microenvironments, especially pH, can affect the insulin-binding affinity to its receptor 4.