Yawning is a normal human behavior. You open your mouth, stretch your arms, and take a deep breath into your lungs to signify you are tired or sleepy. It might even be a mimicked reaction: You see someone else yawn, then you suddenly do it too. However, if you find yourself yawning excessively, this can be a warning sign for a serious medical condition.
Vasovagal Reaction
Excessive yawning is a prodrome (initial symptom) for a vasovagal reaction. Vasovagal reactions, also known as vasovagal syncope, are common causes of fainting. According to the Mayo Clinic, the vagus nerve is a bundle of fibers located in your neck, chest and intestines that regulate your heart and blood vessels. When it is stimulated, you begin to yawn excessively. You can also feel nauseous, lightheaded and break out into a cold sweat. Your heart beats slower and your blood vessels widens. This leads to low blood pressure and the risk of fainting.
Heart Conditions
According to the University of Maryland Medical Center, a heart attack and an aortic dissection (rupture of a large vessel) can cause excessive yawning. These heart conditions can stimulate the vagus nerve, and a vasovagal reaction can result as the heart pumps less and blood pressure lowers.
During a heart attack, the heart does not receive enough oxygen because certain blood vessels in the heart are blocked. The heart muscle pumps less efficiently and the muscle can die. In an aortic dissection, bleeding occurs around a torn blood vessel called the aorta (vessel carrying blood away from the heart) and low blood pressure results.
Excessive Daytime Sleepiness Disorders
Disorders of excessive daytime sleepiness can cause you to yawn excessively. Narcolepsy and hypersomnia are two disorders that cause constant sleepiness. According to PubMed, narcolepsy is characterized by brief sleep attacks. These attacks are irresistible and you cannot fight them. Hypersomnia is characterized by excessive sleepiness at inappropriate moments. Your nighttime sleep extends through the day and excessive yawning becomes a physical symptom.
Many people take naps during the day but nap time in hypersomnia is a compulsion. If you have hypersomnia, you might sleep during a board meeting or while talking to your friend. You should tell your doctor if you experience these symptoms.
