Are cool downs necessary?

A cool-down routine is said to reduce muscle soreness and improve recovery, but the most compelling evidence can be found in the tiny blood vessels within the body. After a long exercise session, blood vessels expand to accommodate the increase in blood flow.

Does cooling down do anything?

Cooling down after your workout allows for a gradual recovery of preexercise heart rate and blood pressure. Cooling down may be most important for competitive endurance athletes, such as marathoners, because it helps regulate blood flow.