Obesity can also cause respiratory problems. Breathing is difficult as the lungs are decreased in size, and the chest wall is very heavy and difficult to lift. Daily activities such as shopping, yard work, stair climbing and exercise may be hindered by breathing problems.

While obesity does not cause asthma or bronchitis, it interferes with breathing and may aggravate an attack. Obesity, however, may cause sleep apnea, a serious condition that occurs when people stop breathing during sleep. When soft tissue in the throat collapses around the airway, a complete blockage occurs and the person stops breathing. In the long-term, sleep apnea can cause high blood pressure, heart rhythm disturbances and sudden death.

For the severely obese, particularly those over 350 pounds, obesity hypoventilation is a concern. Often associated with sleep apnea, this abnormal breathing condition results in the accumulation of toxic levels of carbon dioxide in the blood.