Why do athletes run around the track counter-clockwise?

Answer 1

As the heart is on the left side, for humans and animals, running anticlockwise makes the centrifugal force in the body to act from left to right. Whereas it is from right to left for clockwise running.

Superior venecava takes blood to the heart aided by heart suction. This vein carries blood from left to right. Centrifugal force due to anticlockwise running helps this suction.

If we run clockwise, the centrifugal force impedes suction. That is why, in olden days, health officers ensured that all carnival merri-go-rounds were run only in the anti-clockwise direction.

Racing tracks, animal shows in circuses, bullock-drawn pelt on wheels, all mostly have only left turns. Stairways in temple towers have only left turns for going up.
Clockwise running tires people, especially children, easily.

As we know that if we breathe from left nose hole, cool air will go inside and if we breathe from right nose hole, warm air will go inside. When we run on a circular track anticlockwise, we will breathe from right nose hole .Which will warm up our body and we can run more fast as when we start race, we first warm up our body and then start running.