When symptoms are mild and brief, they may be related to a temporary shortage of blood and oxygen supply due to strenuous exercise, overweight and obesity, and mild cardiopulmonary disease, and may resolve on their own after the patient rests. More severe, recurrent and prolonged shortness of breath in a quiet state may be associated with asthma attacks, acute exacerbation of chronic obstructive pulmonary disease, or acute heart failure, and may require treatment to relieve the symptoms.