Modern medicine does not view 'dyspnea' simply as an issue of lung function alone. It interprets this as a complex bodily signal encompassing the respiratory system, cardiovascular system, nervous system, and even mental health. The lungs in our body play a central role in delivering oxygen from the air into the blood and discharging carbon dioxide. The microscopic structure of the pulmonary alveolus and the efficiency of blood-gas exchange are directly linked to how effectively we absorb oxygen and expel waste products. When there is decreased pulmonary function, oxygen levels in the blood drop and carbon dioxide levels rise, prompting the respiratory center of the brain to stimulate breathing more forcefully, which is when we feel short of breath.
However, many people experience shortness of breath even when there are no specific abnormalities on a pulmonary function test. In this case, we must examine heart function together. The heart plays the crucial role of pumping oxygenated blood received from the lungs throughout the entire body. If the pumping function of the heart weakens, such as in heart failure, it fails to supply as much oxygen as needed to muscles and organs, and this too can lead to dyspnea. In particular, shortness of breath on exertion can be an important sign of decreased cardiac function.
Furthermore, dyspnea can also be explained from a neurological perspective. Hyperactivation of the autonomic nervous system, especially the sympathetic nerve, puts our body into a 'fight-or-flight' state. At this time, breathing becomes rapid and shallow, and as the muscles around the thoracic cage tense up, chest tightness can be felt. This is the exact context in which people experiencing chronic stress, anxiety, or panic disorder complain of dyspnea. Because the respiratory center of the brain regulates breathing patterns by integrating diverse information, including not only oxygen and carbon dioxide concentrations in the blood, but also stress hormones and psychological states, mental health issues often manifest as physical symptoms.
Additionally, mitochondrial dysfunction related to energy production at the cellular level or states of chronic inflammation can also contribute to shortness of breath. When bodily energy is lacking or oxygen utilization drops due to chronic inflammation, the body demands more oxygen, which can appear as increased respiration. Modern lifestyle habits such as smoking, air pollution, obesity, and lack of physical activity act in combination to increase the burden on the lungs and heart, resulting in the symptom of dyspnea. Rather than a problem solely of the lungs or heart, it may be a delicate warning that the balance of our entire body is being disrupted.
