Why we yawn

While the act of yawning is firmly established as an involuntary reflex action, there is more to it than meets the eye. Several theories abound as to why we yawn and there haven't been many studies performed to analyse it as such. A 2013 study published in the International Journal of Applied and Basic Medical Research suggested that the act of yawning helps regulate the temperature in the brain.

Scientists put forward the theory after observing numerous animals (most vertebrates in the animal kingdom) yawn and found that a yawn helps to stretch the muscles of the jaw, which increases the flow of the blood to the head, neck and face. The deep breath that one takes while yawning lets the spinal fluid and blood flow down from the brain, and the cool air inhaled helps in cooling down these fluids in the body.

According to some research on the activity of a foetus inside the womb, published in the journal Early Human Development in 1982, a foetus is capable of performing as many as 16 different movement patterns in the first trimester itself, and spontaneous yawning is one of them.

While some scientists have proposed physiological reasons behind why we yawn (like the above-mentioned theory about stretching the jaw), some say that yawning acts as a means of communication from a psychological standpoint. This theory is particularly important as yawning is seen as an extremely contagious activity (an echophenomena).

The contagiousness of a yawn, according to some experts also suggests that it is not the same as spontaneous yawning, and is an unconscious behaviour. It also suggests that those who yawn after seeing someone else do so or while reading about it indicates a higher level of social interaction and empathy.

It is also known that yawning can also help open up the airway in the ears, enabling you to hear better. However, even though yawning is viewed as a natural reflex action of the body, excessive yawning could be a sign of something more than a simple reaction.

Excessive yawning simply means that a person is seen yawning more than once in a minute. In most cases, excessive yawning is just a sign of feeling too tired or bored. However, in some cases, it can be an indicator of health problems. Read on to know some common causes of excessive yawning:

• Fatigue or drowsiness: As mentioned earlier, the primary cause of yawning is fatigue or extreme tiredness, or feeling drowsy.
• Sleep problems: Sleep disorders such as sleep apnea, insomnia and so on lead a person to yawn due to the tiredness from a general lack of sleep (sleep deprivation).
• Anxiety or depression: The body may react to certain stressful situations, anxiety, depression and certain triggering instances by yawning.
• Some medicines: Some medications such as antidepressants, antihistamines (for allergies) and some painkillers can cause excessive yawning.
• Internal bleeding: Internal bleeding in or around the heart can cause one to yawn a lot.
• Body temperature cues: Inability to control the temperature of the body can also result in yawning.
• Nerves: A vasovagal reaction, which occurs when the vagus nerve in the body is stimulated. This causes the heart to slow down and is presented with symptoms like a sudden drop in heart rate and blood pressure, which can cause a person to faint.
• Brain problems: Yawning a lot is also linked to brain disorders like a stroke, brain tumour, epilepsy or MS (multiple sclerosis).

You may be tempted to attribute excessive yawning to feeling tired and ignore it. However, if you've been yawning a lot more recently and without any good reason, it may be time to get it checked by a doctor.

The doctor will start by asking you about your sleeping pattern. If you have not been getting enough sleep in one go, especially at night, that could be the reason for your excessive yawning. If a sleep disorder is at the root of the problem, then it will have to be addressed using the appropriate therapy (for example, using a CPAP or continuous positive airway pressure machine for sleep apnea).

Next, the doctor may order an EEG or electroencephalogram to measure the electrical activity in your brain. Such a test is commonly done to rule out brain disorders such as epilepsy.

An MRI scan may also be recommended as it can produce detailed images of what is going on inside the body, allowing the doctor to assess your health in a better way. Again, MRIs can also indicate brain disorders or a problem with the spinal cord. They can also help the doctor assess the condition of your heart, to rule out any serious condition as the reason behind your excessive yawning.

Read more: Spinal cord injury

Depending on the reason, the doctor can prescribe an appropriate course of action to bring down the incidence of excessive yawning:

• In the case of an underlying health condition, the doctor would recommend treatment for the disorder with the help of medications and therapies.
• Excessive yawning can also be a reaction to certain medications. In this case, the doctor could either change your medication or prescribe a lower dosage to address the problem.
• In the event of a sleep disorder, the doctor may ask the patient to change their sleeping patterns with the help of physical exercises, a change in diet and daily habits, as well as the use of certain sleep-inducing medications.

As explained above, yawning has both physiological as well as psychological reasons behind it. While the regulation of the body's temperature and sleepiness are among the leading reasons for yawning, it is also seen as a social behaviour as it can communicate one's mental state (like anxiety) and an indicator of health as it can signal some physical conditions (such as internal bleeding).

While yawning in itself is a natural reflex of the body, excessive yawning may be a sign of a deeper, underlying medical problem which must be shown to a doctor to rule out anything serious.