How much did man o war's heart weigh?

Man o' War, the famous racehorse, had a heart that weighed approximately 22 pounds (10 kilograms). This is significantly heavier than the average horse heart, which typically weighs around 8 to 10 pounds (3.6 to 4.5 kilograms). The size of his heart is often cited as a contributing factor to his remarkable speed and endurance on the racetrack.