How does PCV increases in dehydration?

In dehydration, the body loses water, leading to a reduction in plasma volume. This results in a relative increase in the concentration of red blood cells (RBCs) in the bloodstream, as there is less fluid to dilute them. Consequently, the packed cell volume (PCV), or hematocrit, increases because it measures the proportion of blood volume occupied by RBCs. This change is a physiological response to conserve fluid and maintain blood pressure and circulation.