Dysfunctional breathing/hyperventilation syndrome is a breathing problem that involves breathing using a poor pattern or breathing too deeply or too rapidly (or both) (hyperventilation). There are many possible causes of dysfunctional breathing and if left untreated it can lead to a variety of unpleasant symptoms such as breathlessness, dizziness, pins and needles and chest pain. Little is known about dysfunctional breathing in children. Preliminary data suggest that at least 5.3% of children with asthma have dysfunctional breathing but no accepted recommendations are available for the treatment of these children. Dysfunctional breathing is currently treated using breathing exercises where the overall aim is to teach the patient to breathe gently using the lower part of their chest at a rate that matches their activity level.