3. Shortness of breath

Strenuous exercise, extreme temperatures, obesity and high altitude all can cause shortness of breath. Shortness of breath also could be a sign of another health problem. If you have unexplained shortness of breath, especially if it comes on suddenly and is severe, seek emergency medical care.

Causes for breathlessness might include chronic obstructive pulmonary disease, bronchitis, asthma, pneumonia or a blood clot in the lung (pulmonary embolism). Other causes include heart and lung problems. Difficulty breathing can also occur with a panic attack — a sudden episode of intense anxiety that triggers severe physical reactions when there is no real danger or clear cause.