Breathing is an essential aspect of our existence, yet it is often taken for granted. However, beyond the basic act of inhaling and exhaling, the human body is capable of performing a range of fascinating and unusual breathing reflexes.
From the protective cough reflex that helps clear our airways to the contagious yawn that increases alertness and cognitive function, each of these reflexes serves a unique purpose in maintaining our respiratory health and well-being.
Unusual Breathing Reflexes
In this article, we will explore the most intriguing breathing reflexes, delving into the science behind these remarkable automatic responses and their impact on our lives. This includes the following:
- Cough reflex
- Sneeze reflex
- Mammalian diving reflex
Keep reading to learn more about these breathing reflexes and how they help keep our respiratory system functioning optimally.
The cough reflex is a protective mechanism that helps clear the airways of foreign substances such as mucus, dust, or irritants. It’s triggered by the stimulation of specialized nerve endings in the airways, which signals the brain to initiate a forceful expulsion of air.
The cough reflex also helps maintain clear airways by increasing the flow of mucus and helping to remove any debris that has accumulated in the airways.
The cough reflex can be voluntary or involuntary and is essential for maintaining healthy lung function and preventing respiratory infections.
The sneeze reflex is an automatic, explosive exhalation of air through the mouth and nose and is triggered by irritation in the nasal passages. It’s a protective mechanism to clear the nasal passages of foreign substances such as dust, pollen, or other irritants.
The sneeze reflex is initiated by the mucous membranes of the nasal passageways, which signal the brain to initiate the explosive exhalation of air.
Sneezing also helps to increase airflow in the nasal passages, which helps remove any accumulated debris and maintain healthy breathing.
Sneezing is also a symptom of respiratory infections or allergies and can spread infectious particles to others if the mouth and nose is left uncovered.
Hiccups are an involuntary contraction of the diaphragm and the epiglottis, followed by a quick closing of the vocal cords, producing the “hic” sound. The exact cause of hiccups is not well understood.
Still, they can be triggered by several factors, such as:
- Eating too quickly
- Drinking carbonated drinks
- Alcohol consumption
- Sudden temperature changes
Hiccups typically last only a few minutes but can persist for hours or even days in rare cases. Several remedies can help alleviate hiccups, including holding your breath, drinking a glass of water quickly, or swallowing sugar.
In most cases, hiccups resolve on their own and do not require medical attention. Sedatives are used to treat hiccups in severe cases.
The yawn reflex is an instinctive, contagious act of opening one’s mouth wide and inhaling deeply, often accompanied by a sigh. Yawning is most commonly associated with feelings of fatigue or boredom.
However, it can also occur due to changes in brain oxygen levels, shifts in the sleep-wake cycle, or as a response to stimuli such as the sight or sound of others yawning.
While the exact purpose of yawning is not well understood, it is believed to increase oxygen and blood flow to the brain and cool the brain temperature, potentially improving alertness and cognitive function.
Yawning is a natural and common behavior seen in many species, including humans, and is not considered a cause for concern unless it is frequent or accompanied by other symptoms.
Hopefully, you’re not yawning while reading this article.
Sighing is a deep and prolonged exhalation that is often accompanied by a feeling of relief or frustration.
Sighing serves a functional purpose in maintaining lung volume and relieving pressure in the chest, as it helps to regulate airflow and oxygen levels in the body. Additionally, sighing can also serve as a physiological response to emotional stimuli, such as stress, boredom, or sadness.
It is believed that sighing may help to regulate emotions and release pent-up tension. Furthermore, it can signify a change in the emotional state of others.
Sighing is a natural and normal behavior that occurs regularly in most individuals and is not typically a cause for concern unless it is frequent or accompanied by other symptoms.
Mammalian Diving Reflex
The mammalian diving reflex is an automatic physiological response that occurs when the body is submerged in cold water.
Cold water stimulates sensory neurons, which increase parasympathetic activity. This results in a cessation of breathing, bradycardia, and a slow metabolism. It also causes peripheral vasoconstriction and the shunting of blood to vital organs, such as the heart, lungs, and brain.
Note: The mammalian diving reflex only occurs in cold water with a temperature less than 20 ºC (68ºF). It does not occur during simulated dives in warm water.
This reflex is thought to have evolved as a survival mechanism in marine mammals, allowing them to dive for extended periods in search of food or to avoid predators.
In humans, the diving reflex can be trained and harnessed for therapeutic purposes, such as slowing the heart rate during medical procedures or reducing anxiety and stress levels.
The diving reflex is a complex and fascinating aspect of human physiology, demonstrating the adaptability and survival mechanisms of the human body.
As you can see, our bodies are capable of performing a wide range of fascinating and unusual breathing reflexes. Each has a unique purpose and impact on our health and well-being.
From the cough reflex that helps clear our airways to the mammalian diving reflex that conserves oxygen, these reflexes demonstrate the incredible adaptability and survival mechanisms of the human body.
Understanding these reflexes gives us a deeper appreciation for the complex and intricate workings of our respiratory system and the remarkable abilities of the human body.
So, the next time you hiccup, sneeze, yawn, or dive into a (very cold) pool, take a moment to appreciate the fascinating breathing reflex that your body is performing.
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
- Sharma, Sandeep, et al. “Cough.” National Library of Medicine, Jan. 2022, www.ncbi.nlm.nih.gov/books/NBK493221.
- Songu, Murat, and Cemal Cingi. “Sneeze Reflex: Facts and Fiction.” Therapeutic Advances in Respiratory Disease, vol. 3, no. 3, SAGE Publications, June 2009, pp. 131–41. https://pubmed.ncbi.nlm.nih.gov/19617285/.
- Vaschillo, Evgeny G., et al. “The Effects of Sighing on the Cardiovascular System.” National Library of Medicine, 1 Mar. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4386588.
- Gupta, Sharat, and Shallu Mittal. “Yawning and Its Physiological Significance.” National Library of Medicine, www.ncbi.nlm.nih.gov/pmc/articles/PMC3678674.
- Cole, Justin A. “Singultus.” StatPearls – NCBI Bookshelf, 7 Aug. 2022, www.ncbi.nlm.nih.gov/books/NBK538225.
- Michael Panneton, W. “The Mammalian Diving Response: An Enigmatic Reflex to Preserve Life?” Physiology, vol. 28, no. 5, American Physiological Society, Sept. 2013, pp. 284–97. https://doi.org/10.1152/physiol.00020.2013.