Answer: It can decrease oxygen flow to the brain, causing fainting, seizures and brain damage
Explanation: For most people, it's safe to hold your breath for a minute or two. Doing so for too much longer can decrease oxygen flow to the brain, causing fainting, seizures and brain damage. In the heart, a lack of oxygen can cause abnormalities of rhythm and affect the pumping action of the heart.
Note: This is from a reliable Heath website!