You can yawn for many reasons; a yawn often happens when you are bored or tired. While it was once believed that you yawned when you needed more oxygen, that theory has been disproved. Everyone yawns throughout the day; however, if yawning becomes excessive, it may be indicative of a serious medical problem. If you think you have an underlying condition, talk to your doctor about your symptoms.
Yawning is a natural response when your body is tired. However, according to the National Institutes of Health, if it happens a lot, it may be a sign of a sleep disorder, which can include insomnia, sleep apnea and narcolepsy. These conditions may inhibit you from getting a deep and restful night's sleep and will leave you tired during the day, making it hard to concentrate. With conditions such as sleep apnea and narcolepsy, you may not be aware that you have these conditions. In these cases, daytime fatigue and excessive yawning may be your only warning sign that something is wrong. Chronic fatigue or tiredness that interferes with daily activities and work should be discussed with your physician.
Heart Rhythm Abnormalities
If the supply of blood and the oxygen it carries to your brain is reduced enough, you may develop fainting spells called "syncope." This can be a temporary condition, occurring when you stand for too long, stand up too quickly, are under stress, or not feeling well. However, it can also mean that you have a heart condition. High or low blood pressure and heart rhythm irregularities can also restrict blood flow to the brain. With either situation, if your brain is not getting the blood and oxygen it needs, you may develop many symptoms including excessive yawning. If you tend to yawn more than normal and have other symptoms such as lightheadedness or fainting, see your physician to rule out serious illness.
Aortic dissection is a tear in the aorta--the major artery that carries blood away from the heart. This condition can be inherited or can be due to a disease such as high blood pressure and coronary artery disease, both of which place a strain on the artery walls. According to the Mayo Clinic, this condition can make your short of breath and tired, which can contribute to excessive yawning. If your yawning is accompanied by trouble breathing, sweating, irregular pulse, chest pain or any other warning signs of a heart attack or stroke, you should seek medical attention.