The question of whether a person exhales before dying is one that has fascinated people for centuries. While we may never know for certain what happens in a person’s final moments, science can provide some clues as to whether exhalation tends to occur at the point of death. In this article, we’ll explore some quick answers to questions around this topic and delve deeper into the evidence around exhaling and dying.
Quick Overview: Do people exhale before death?
In short, the evidence suggests that in most cases, people do exhale shortly before death. This is because breathing is an involuntary process controlled by the brain stem, which continues to function even as other parts of the brain shut down. As the body starts to shut down, however, the breathing patterns become abnormal, often with longer pauses between breaths. This eventually leads to a final exhalation.
What causes the final exhalation?
The final exhalation seems to occur due to the way breathing patterns change as the body declines. Breathing first becomes irregular, then eventually stops altogether as the brain stem ceases functioning. The lungs deflate passively after the last breath, creating an appearance of an active exhalation.
Are there exceptions where no exhalation occurs?
In some cases, no identifiable final exhalation occurs. This may happen with brain injuries where the brain stem is damaged or death is very sudden. But in most scenarios, the involuntary breathing processes create a final exhalation.
Is the long exhalation just a myth?
While the “long last breath” is exaggerated in some myths and films, scientific evidence confirms that a noticeable final exhalation tends to occur in the moments before death.
The Science Behind Exhalations and Death
To better understand why final exhalations tend to occur, let’s look at some of the scientific research around breathing and brain activity during death.
How breathing is controlled
Breathing is regulated involuntarily by a network of neurons in the brain stem known as the respiratory center. Even when we are unconscious, this area continues to signal the diaphragm and intercostal muscles to contract, allowing breathing to continue.[1]
Breathing irregularities as death nears
As a person nears death, changes start occurring in their breathing patterns due to the shutting down of the body:[2]
- Breathing may become more rapid, then start slowing down.
- Irregular pauses develop between breaths.
- Noisy “rattling” breaths may occur as air passes through fluid-filled airways.
- Periods of no breathing (apnea) increase until breathing stops completely.
These irregularities occur because the brain stem, while still functioning, is beginning to lose its ability to correctly regulate the breathing cycle. The abnormalities typically worsen until breathing fully stops.
The final exhalation
As breathing becomes more sporadic near death, the irregular cycles often end with an exhalation. There are a few reasons this likely happens:[3]
- When pausing between breaths, the respiratory center tends to switch off during exhalation rather than inhalation.
- Dying neurons in the brain stem start misfiring, affecting the breathing cycle.
- Lung deflation occurs passively after the last breath due to airway relaxation.
These effects cause the respiratory cycle to often end in an exhalation, creating the appearance of a deliberate final breath being taken. In reality, it reflects the declining state of the brain stem.[4]
Cases where no final exhalation occurs
While exhalation before death is the norm, some exceptions exist:[5]
- Sudden deaths – For example, a fatal gunshot wound to the head may damage the brain stem instantly, preventing a final breath.
- Brain stem damage – Injuries, tumors, or diseases affecting the brain stem can disrupt the respiratory center and prevent a terminal exhalation.
- Respirator use – People on ventilators who are removed from the machine often have no final breath, as the machine had taken over breathing.
So in certain situations, normal breathing mechanisms may be impaired, creating a different pattern around death.
Chemical Changes Associated with Final Exhalations
Research has also analyzed the chemical composition of the last breaths to understand what occurs at the point of death:
Carbon dioxide levels
Studies have confirmed dying breaths contain very high levels of carbon dioxide – as much as 10 times normal levels.[6] This buildup occurs due to the body’s declining ability to exchange gases.
Ketones
Ketones produced through fat metabolism have been found in the breath of dying patients and animals.[7] Their presence may relate to changes in metabolism and organ function.
Odor
In some cases, a distinctive sweet, floral odor has been reported in the last breaths of those dying.[8] The cause remains unclear but could indicate metabolic changes.
So the chemical composition of final exhalations differs significantly from normal breath. However, more research is still needed to fully understand these changes.
Duration of the Final Exhalation
Another question surrounding the last breath is whether it lasts for an abnormal length of time. Are the final moments prolonged, or do they pass quickly?
Perceptions may be misleading
Subjectively, observers often report an exaggerated, lengthy final exhalation from those dying. However, this perception is likely distorted. Studies using respiratory monitors show dying breaths are often no longer than normal ones.[9]
Why the perception is distorted
Several factors may create the illusion of a prolonged exhalation:[10]
- The breath is given added significance as the “last.”
- Longer pauses tend to precede the final breath, magnifying its perception.
- It occurs amidst silence rather than normal breathing sounds.
- The breath may be vocalized, making it more noticeable.
So while the final breath seems long, objective measurements show it lasts a normal length of time in most cases.
Conclusion
In conclusion, scientific evidence indicates that the majority of people do exhale shortly before dying. This reflects the shutting down of the brain stem that regulates breathing. An abnormal but recognizable breath usually precedes the very last exhalation. However, some exceptions exist when brain stem damage occurs. Actual measurements show the final breath is not prolonged, but its significance makes it seem subjectively longer. Understanding the role of breathing at the end of life provides insight into a process that has long fascinated human beings.