Shortness of breath--fatigue--is one variable, and pain in the legs is another that is responsible for losing a race. When pain causes the loss, the racetracker says, "Wouldn't blow out a candle." Of course, weight carried and other factors like ą pain-killing phenylbutazone all affect performance. How long does the raced or worked walking horse take to regain normal breathing? Please review the vital signs for horses.