A breather is like taking a break for your body. Just like you need to rest when you run and play a lot, your body needs to rest too when it works really hard. When you breathe in and out, your body takes in oxygen and gives out carbon dioxide. Too much carbon dioxide can be bad for your body, so you need to breathe in more oxygen to balance it out. Taking a breather means that you rest and take deep breaths, so your body can get more oxygen and get rid of the carbon dioxide. It's like hitting the reset button so your body can go back to being happy and healthy!