Exhalation takes place when the diaphragm relaxes, returning to its dome shape and pushing air out in the lungs. This rhythmic contraction and relaxation are essential for protecting ordinary respiration and ensuring ample oxygen provide to your body.Thi?t b? ho?t ??ng không s? d?ng ?i?n n?ng nên giúp ti?t ki?m ???c m?t kho?n chi phí r?t l?n.??