What effect does consuming a high-salt meal have on blood volume?

Consuming a high-salt meal temporarily increases blood volume due to the osmotic properties of sodium. When there is an increase in sodium intake, the body retains additional water to balance the sodium levels in the bloodstream. This is largely facilitated by the kidneys, which respond to elevated sodium levels by reabsorbing more water to maintain homeostasis in the blood’s osmolarity.

As the sodium concentration in the extracellular fluid rises, it creates an osmotic gradient that draws water from the intracellular compartments into the extracellular space, thus increasing the overall blood volume. This elevation in blood volume can lead to increased blood pressure, at least in the short term, as more fluid is present within the circulatory system.

The other options do not accurately reflect the physiological response to increased salt intake. A decrease in blood volume would not occur with high salt consumption; similarly, a scenario with no effect would negate the osmotic impact of sodium. Dehydration is also unlikely, as excess salt intake leads to water retention rather than loss. Thus, the understanding of fluid balance and osmosis clearly supports that a high-salt meal results in a transient increase in blood volume.