What physiological condition can be deadly if blood pH falls too low?

Acidosis occurs when the blood pH drops below the normal range (7.35-7.45), indicating an excess of hydrogen ions (H+) in the blood, which leads to a more acidic environment. This condition can significantly impair various physiological processes, including enzyme activity, electrolyte balance, and oxygen availability. The central nervous system and the cardiovascular system can be particularly affected by acidosis, leading to symptoms such as confusion, lethargy, and even loss of consciousness in severe cases.

If acidosis is severe and left untreated, it can result in life-threatening complications, including respiratory failure, shock, and arrhythmias. The body has mechanisms to compensate for acidosis, such as increased respiratory rate to remove carbon dioxide and renal excretion of hydrogen ions, but these may not be sufficient in cases of severe disturbance.

In contrast, alkalosis indicates a rise in blood pH, dehydration refers to fluid loss that affects electrolyte balance but does not directly relate to blood pH, and hyperthermia relates to elevated body temperature rather than pH levels. Therefore, acidosis is the condition that poses the most dire consequences with a critical drop in blood pH.