Following are terms that specify a type of lung size and/or activity. More specific definitions may be found in individual articles.

• Eupnea – normal breathing
• Apnea – absence of breathing
• Bradypnea – decreased breathing rate
• Dyspnea or shortness of breath – sensation of respiratory distress
• Hyperaeration/Hyperinflation – increased lung volume
• Hyperpnea – fast and deep breathing
• Hyperventilation – increased breathing that causes CO₂ loss
• Hypopnea – slow and shallow breathing
• Hypoventilation – decreased breathing that causes CO₂ gain
• Labored breathing – physical presentation of respiratory distress
• Tachypnea – increased breathing rate
• Orthopnea – Breathlessness in lying down position relieved by sitting up or standing
• Platypnea – Breathlessness when seated or standing, relieved by lying flat
• Trepopnea – Breathlessness when lying flat relieved by lying in a lateral position
• Ponopnea – Painful breathing