Occasional yawing is quite natural. You should, however, start taking notice when excessive yawning becomes part of your daily routine. It may very well be your body’s way of alerting you to an underlying problem.
What Happens When You Yawn?
Yawning is an involuntary process. Your mouth opens wide, and you breathe in air, filling your lungs. The eardrums stretch and extra oxygen are carried to the brain and other parts of the body through the blood, making you more alert. Sometimes a yawn is of short duration. Other times, it is a long and drawn-out, accompanied by stretching.
We are all subject to the occasional yawn throughout the day, but most of the time, there are certain conditions during which we yawn.
We yawn before bedtime when we are tired, and the brain starts slowing down. We yawn when we wake up in the morning. It is almost as if this triggers our body to get into “wake up mode”. We also tend to yawn when we get bored, as the brain becomes less stimulated. In all these instances, yawning is a way to force blood, and thus oxygen, to the brain in order to increase alertness.
Lastly, we often yawn when we see someone else yawn, or when we read about the topic. Have you yawned yet?
The Physiology of Yawning
When you yawn, the thoracic muscles in your chest, your diaphragm, your larynx (in your throat), and the palate of your mouth are all involved. Yawning also helps wet your lung’s air sacs. Air is inhaled, accompanied by a stretching of the eardrums, followed by an exhalation. There is, so far, much speculation about what causes this and not enough research to be conclusive.
We do not always yawn when we are tired. You may run a marathon and be deathly tired afterward, but not yawn. Too little oxygen to the brain may also not be a deciding factor for yawning. This is because the lungs are not usually filled to their full capacity, although deep breathing, of its own accord, does tend to keep your lungs healthy. For those in a catabolic state, with reduced rib cage expansion resulting in less oxygen in the blood, yawning may help this issue, but the majority of people require a different explanation for yawning.
Although people are prone to excessive yawning when bored, more recent studies show that the most likely reason for yawning is the body’s effort to cool down your brain. The most recent, and possibly best scientifically based study, points to this, indicating that people tend to yawn more in summer than winter, possibly due to the brain using this reaction in order to cool down.
Yawning is normal. However, excessive yawning can be due to certain medical conditions.
One cause is what is termed a “vasovagal reaction”. Besides yawning, symptoms often associated with vasovagal reactions include blurred vision, a clammy sweat, lightheadedness, pale skin, nausea, and tunnel vision. Vasovagal reactions happen when part of your nervous system that sees the regulation of blood pressure and heart rate is compromised and no longer responds as it should. This is often seen in stressful situations or when you feel you are in danger. The result is that your heart rate slows down, the blood vessels in your legs dilate, excessive blood moves into your legs, and your blood pressure drops. This drop in heart rate and blood pressure results in less blood reaching the brain. The body may automatically try to up its oxygen intake (by means of yawning) in order to ensure oxygen reaches the brain.
A vasovagal reaction and the accompanying excessive yawning may also be due to internal bleeding in the aorta area or indicate that you are about to have a heart attack or have heart issues.
Common causes of excessive yawning
The most common reasons for excessive yawning include the following:
- A vasovagal reaction – As has been mentioned, a vasovagal reaction often has excessive yawning as a symptom.
- Fatigue – Often, when tired, we start yawning excessively. The extra oxygen released into the blood is the body’s way of trying to stay alert.
- Medications – Certain medications can lead to excessive yawning, mainly because they make you sleepy. These medications include antihistamines, certain pain medications, antidepressants, and selective serotonin uptake inhibitors.
- Liver disease – The last stages of liver failure are often accompanied by excessive yawning. One of the possible causes for this reaction is the accompanying fatigue experienced during this time.
- Multiple sclerosis (MS) – Studies indicate that those who suffer from MS have a tendency towards excessive yawning. It seems yawning provides symptomatic relief from MS. Additionally, those with MS also tend to have a thermoregulatory dysfunction whereby they are unable to control their body temperature. Yawning tends to cool the body down.
- Epilepsy – Epileptic seizures can result in permanent brain damage that irritates the part of the brain sending out certain signals, leading to excessive yawning. This, however, is rare.
- Sleeping disorders – Sleeping disorders such as insomnia or sleep apnea may cause constant tiredness, leading to excessive yawning throughout the day.
- Brain dysfunctions – Research indicates that a brain tumor or stroke may lead to excessive yawning and can be linked to lesions in the brain stem. Yawning can also result from compression of the hypothalamus or the pituitary gland.
- Overstimulation of the parasympathetic nervous system – The parasympathetic nervous system is a division of the autonomous nervous system. It is primarily concerned with slowing down the heart rate, conserving energy, and overseeing the activity of different glands. When this system is compromised, it often leads to excessive yawning.
- Hypoglycemia – Excessive yawning is one of the first signals of hypoglycemia in diabetics.
Theories About What Makes You Yawn
There has been much speculation as to why people yawn. Hippocrates, for example, in 400 B.C. suggested that yawning might be a response to fever, in order to get rid of any bad air in the body. He likened the process to that of steam escaping from a pot of boiling water.
Centuries later in 1923, British neurologist Sir Francis Walshe noticed that partially paralyzed patients seem to regain certain motor functions during the few second duration of a yawn. He found certain patients who were unable to flex their fingers could do so when yawning. He concluded that the yawning process was a very primitive process in the brain and something we have no conscious control over.
Johanna de Vries, an obstetrics professor in Amsterdam, observed that one of the first things humans do, even during the fetal stage, is a yawn. Robert Provine, a neuroscientist, indicated that yawning is indeed a spontaneous action and part of our biological programming. We have no control over it.