Which heat injury occurs when excessive blood pools in the extremities after standing following marching or exercise?

• A. Heat cramps
• B. Heat syncope
• C. Heat exhaustion
• D. Heat stroke

Answer: (B)

Heat syncope happens when standing after marching or exercise in the heat leads to a lot of blood collecting in the vessels of the legs and abdomen. The body’s vessels dilate to dump heat, and once you stop moving, the leg muscles aren’t helping pump blood back to the heart. That combination lowers the amount of blood returning to the heart, which reduces blood flow to the brain and can cause fainting or near-fainting. It's a transient orthostatic issue tied to heat and recent activity, often with dehydration making it more likely.

Heat cramps are muscle spasms from electrolyte and fluid loss during intense activity, not primarily about pooling after standing. Heat exhaustion is dehydration and heat-related fatigue with symptoms like weakness, dizziness, and sweating but not specifically fainting from venous pooling after stopping. Heat stroke is a life-threatening failure of heat regulation with very high core temperature and altered mental status, requiring urgent care.