Reviewed by Dr Nurul Aishah Jamaludin, Physician Ignatius Ooi Yong Chin and Physician Wong Si Xuan

Why Do We Yawn? Here are a Few Surprising Theories

Published February 12, 2023| 4 min read

Why do we yawn? Find out why we do it and what it could mean if you’re yawning excessively throughout the day.

Woman yawning while covering her mouth with her left hand as she sits at a desk in front of a desktop computer.

Everybody yawns when they’re bored or sleepy. If we see someone with their mouths agape, we yawn involuntarily because it’s contagious. Just thinking about it makes us yawn! So why do we do it?

There are different theories as to why people yawn. While it’s completely normal, excessive yawning may indicate a more serious condition. Find out why we yawn and how to stop if you’re doing it frequently.

Popular Theories on Why We Yawn

Recent research suggests that yawning isn’t just a sign of fatigue. There are important physiological and social functions for it too.

But if you’re yawning several times within a 15-minute period, it isn’t just considered rude. It may be a sign you have a neurological condition such as:

Epilepsy
Multiple sclerosis
Brain tumour or swelling

Occasional use of antidepressants, opioids, dopaminergic drugs, and benzodiazepines may also make you yawn. Sleep disorders like insomnia and obstructive sleep apnoea can also provoke it.

Theory #1: It increases blood oxygen levels

One theory is that you yawn when your body is deprived of oxygen. Yawning takes place naturally to improve your breathing by bringing more oxygen into your blood and drawing carbon dioxide out.

Theory #2: It stretches your lungs and lung tissues

Woman looking at her laptop while holding a pen in her left hand and using her right to scroll as she sits at a high desk. — Yawning helps you focus better throughout the day.

Another theory is that yawning may help flex your muscles and joints. This will increase heart rate and alertness, making you feel more awake.

Theory #3: It lubricates your lungs and prevents organs from collapsing

Yawning is supposed to support the redistribution of an oil-like substance called a surfactant. This lubricates the inside of the lungs, preventing them from collapsing.

Theory #4: It exerts a cooling effect on the brain

Yawning helps maintain brain thermoregulation, a process where the brain stays at its core temperature, by contracting the facial muscles. Research has shown that cooling the brain increases mental alertness.

A separate study of 40 men and women between the ages of 20 to 40 found that the average brain temperature was 38.5°C, with deeper brain regions having a temperature exceeding 40°C.

The study also learned that brain temperature was mostly influenced by gender, age, time of day, and region of the brain.

How Traditional Medicine Views Drowsiness

Eu Yan Sang Physician Ignatius Ooi notes, ancient Traditional Chinese Medicine (TCM) literature has a unique perspective on excessive daytime sleepiness, which leads to yawning.

It refers to daytime sleepiness as “feeling tired throughout the day, having trouble sleeping, and feeling groggy when waking up.”

In TCM, excessive yawning happens when there is:

Dampness due to Spleen weakness (asthenia)
Excessive yin due to Yang (active energy) Deficiency
Yang Deficiency due to chronic illness or old age
Brain Deficiency due to a lack of nourishment

How to Treat Excessive Yawning

Excessive yawning can be a sign of Heart, thyroid, and neurological disorders.

Some lifestyle changes may help, such as changing your sleeping position and managing stress levels.

zhao hai — Located on the inside of the foot, the depression below the tip of the medial malleolus.

nei guan — Nei guan is located on the front of the forearm, 3-fingers breadth above the transverse crease of the wrist. It restores and enhances the heart’s function for improved qi and blood circulation within the meridians.

gong sun — Gong sun is on the inner foot, in the depression below the base of the first metatarsal bone.

An illustration of san yin jiao acupoint to help support the kidney in an osteoporosis alternative treatment — Sanyinjiao (SP6, 三陰交) is located on the inner lower leg, about 4-fingers-breadth above the tip of the ankle bone.

An illustration of zusanli to maintain overall health — Zu san li is located on the front of the lower leg, 4 fingers-breadth below the knee joint.

Feng long — Located on the shin, eight fingers-breadth below the depression of the knee joint, two fingers-breadth from the anterior crest of the shin. It dispels pathogens to improve qi and fluid circulation within the meridians and strengthens the stomach’s function.

Herbal remedies like chicken essence, milkvetch root (huang qi, 黄芪), cordyceps (dong chong xia cao, 冬虫夏草), and lingzhi (灵芝) can be taken to increase alertness. Certain acupoints can also be massaged to treat daytime sleepiness.

Dampness can be resolved by performing acupressure on these acupoints:

Zhao hai (KI 6, 照海)
Nei guan (PC6, 內关)

Gong sun (SP4, 公孙)
San yin jiao (SP6, 三阴交)
Zu san li (ST36, 足三里)
Feng long (ST40, 丰隆)

Nei guan, san yin jiao, and zu san li can also help regulate Blood, Qi, Spleen, and stomach Deficiencies.

So why do we yawn? It’s our body’s natural way of taking in more oxygen. If you think you’re overdoing it more than usual, and it’s accompanied by other symptoms, do speak to a medical practitioner.

Consult a licensed TCM physician if you want to try herbal remedies and treatments to ease your excessive yawning. They’ll prescribe what suits you best and you’ll avoid any contraindications. 

Do you know someone who yawns excessively? Share this article with them if you think it’ll help.