It remains a major respiratory functional complaint in cardiac and neuromuscular diseases.
Dyspnea is a daily clinical problem for the cardiologist, affecting a quarter of the general population and half of patients with chronic cardiac diseases.
Suppose the latest advances allow a better understanding. In that case, we are still far from being able to quickly identify its origin and, therefore, solve to improve the quality of life of many patients.
Dyspnea is possible in healthy subjects, for example, during intense exertions, at high altitudes, or when experiencing strong emotions or panic attacks.
Exertional dyspnea is a source of disability, which varies depending on the patient’s activities.
The same dyspnea on exertion is usually more or less disabling since it refers to a worker who requires physical effort or, on the contrary, is a passive subject.
Dyspnea is usually accompanied by orthopnea: where the patient experiences an invincible need to depend on several pillows to breathe better in a semi-sitting position or a sitting position with the legs hanging over the bed or in a chair.
Causes of dyspnea on exertion
Dyspnea is, along with asthenia, the main symptom of left heart failure.
However, it is not a synonym for heart failure since it may be due to bronchopulmonary disease, anemia, or cardiovascular maladjustment to physical exercise, especially in a passive subject.
Finally, it can be of nervous origin; it is characterized by one or two substantial respiratory movements; this “sighing phenomenon,” although physiological, can make people panic.
Dyspnea during heart disease is usually a polypnea (a fast ventilatory rhythm), a feeling of thirst for air. Considering that the ventilatory frequency of regular rest in adults is less than 15 per minute.
This polypnea can occur simply with exertion before becoming permanent at rest.
According to the subjects who suffer from it, the perception of dyspnea can be more or less painful and difficult to bear, which later leads to a malfunction in the ventilation needs of the organism.
Exertional dyspnea clinical scales
Indices, questionnaires, and scales to quantify dyspnea during activities of daily living and exercise are used to assess the general state of the patient.
However, only functional respiratory examinations objectively quantify lung volumes.
Quantification of exertional dyspnea
It is important to quantify, even subjectively, the importance and evolution of exertional dyspnea, especially under the influence of treatments.
The commonly used classification is as follows:
- Class I: dyspnea on exertion exclusively for extraordinary efforts.
- Class II: dyspnea excluded for significant stresses in daily life, such as brisk walking or climbing more than two floors.
- Class III: dyspnea on exertion exclusively for modest efforts in daily life, such as walking on level ground at average speed or climbing less than two stories.
- Class IV: permanent dyspnea, rest and exertion, confining the patient to the home or the room.
The 6-minute walk test performed under well-defined technical conditions can be used for patients who are functionally very limited.
To measure the distance that a patient can walk, it is estimated that the adult patient must travel approximately 400 meters during this period.
Since exertion is the tell-tale mechanism for dyspnea, the cardiologist involved in exercise is often asked to provide diagnostic guidance.
Dyspnea is an uncomfortable perception of breathing, a subjective fear reported by the patient that only the patient will express and be able to quantify.
Its tolerance and expression depend on subjectivity, previous patient experience, emotions, and individual psychology.
Dyspnea is one of the first reasons for consultation and is very common in patients with chronic cardiac or respiratory disease and obese or simply sedentary subjects.
It responds to an insufficiency between the ventilatory demand and the response generated by effort.
Dyspnea on exertion and breathing
The control of respiration originates in the sensitive cortex due to a corollary discharge that emanates from the voluntary and involuntary centers.
The control of ventilation depends on bulbar respiratory centers, which receive peripheral signals from the central systems, from where the efferent nerve impulses are sent that allow a ventilatory response that is in line with the metabolic demand.
When you re-perform an exercise or effort, it is normal for the ventilatory demands of the body to increase, intensifying dyspnea, as it is disproportionate to the amount of ventilation.
During an increased load test with the measurement of gas exchange, we observe excessive ventilation that arises due to the intensity of effort.
The treatment of exertional dyspnea will depend on the cause and therapy with:
- Oxygen Therapy.
- Physical training.
- Biventricular electrostimulation.
- Respiratory muscle training.
- Non-invasive ventilation.
- Lung volume reducing surgery.