Orthopnea
Orthopnea is a condition that causes shortness of breath during sleep. The word orthopnea means “straight lung,” which describes how a person’s lungs feel when they have this condition.
Low sodium is a possible cause of orthopnea. When they don’t have enough sodium in the blood, it can cause fluid to build up in certain body parts, including the lungs and sinuses. This leads to pulmonary edema—when excess fluid builds up in the lungs and causes them to swell up or fill with fluid (edema).
When that happens, it can make it hard for a patient to breathe while lying down at night because this extra weight makes it harder for them to fill up with oxygen while lying down flat on the back or side, as most people do when they’re sleeping.
This is why people with low sodium levels often wake up during the night with shortness of breath and other symptoms. These include coughing from having difficulty breathing correctly through their noses due to congestion caused by increased levels of mucus production.
