What happens if you hold your breath for too long? i know you'll eventually faint but is there any serious dangers like brain damage or death?

Holding one's breath: Your brain will not allow you to hold your breath to the point of death or brain damage. A very subconscious reflex will cause you to take a breath before any damage is done.

No danger: If you hold your breath for too long you will lose consciousness before brain damage can occur. However, there is a danger of head injury from the loss of postural tone and fall.