Symptoms:

The main symptoms of OHS are due to lack of sleep and include:

• Daytime sleepiness
• Depression
• Headaches

Symptoms of low blood oxygen level (chronic hypoxia) can also occur, such as shortness of breath or feeling tired after very little effort.

Signs and tests:

People with OHS are usually very overweight. A physical exam may reveal:

• Bluish color in the lips, fingers, toes, or skin (cyanosis)
• Signs of right-side heart failure (cor pulmonale), such as swollen legs or feet, shortness of breath, or feeling tired after little effort
• Reddish complexion

Tests used to help diagnose and confirm OHS include:

• Arterial blood gas
• Chest x-ray to rule out other possible causes
• Lung (pulmonary) function
• Sleep study

Doctors can tell OHS from obstructive sleep apnea because patients with OHS have high carbon dioxide levels in the blood when awake.