Deep breathing is not about taking in as much air as you can in a second.
That would be like giving a one-hour yoga class in five minutes, or condensing an eight-hour workday into one hour
Deep breathing is taking a long, slow breath to give your nose as much time as possible to filter, moisten and temper the air. This way it enters in the best conditions in your lungs. Your brain and your body will thank you (deeply).