Introduction
Polluted air contains many harmful substances that directly affect human health, plants, and the environment. Through multiple mechanisms, it is discovered that physical activity is directly linked with the environment, such as polluted air. It is the biggest threat when physical activity is exposed to air pollution. It can cause premature morbidity and mortality. Many epidemiologists (a person who studies the area of medicine concerned with the occurrence, distribution, and potential control of diseases) provide evidence regarding the relationship between air pollution and physical exercise for acute health results. Outdoor physical activity may have dual effects on cardiovascular disease risk. Aerobic exercise is good for health. Excessive exercise in polluted air can affect cardiovascular health. Great efforts should be made to educate the patients about the risk of air pollutants. There are no tried-and-true strategies to lower the risk and fatality rate. However, some measures can be taken to reduce air pollutant exposure during exercise. It may help to lessen air pollutants and reduce the risk of cardiovascular risk. This article explains the cardiovascular risk of exercising in polluted air.
What Is Polluted Air?
The air which contains contaminated substances causes harm to human health and other living beings. It also damages the environment. The substances which directly cause air pollution are known as primary pollutants (sulfur dioxide). The mixture of solid and liquid components of different sizes and chemical compositions is called particular matter (PM).
There are two types of air pollutants:
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Primary Pollutants - The pollutants directly released into the atmosphere are called primary pollutants. The primary gaseous pollutant produced by incomplete fossil fuel combustion is carbon monoxide (CO). The carbon monoxide binds with hemoglobin which leads to the formation of carboxyhemoglobin (COhb). It limits the oxygen-carrying capacity of the blood. Therefore, the oxygen delivered to the tissues is affected.
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Secondary Pollutants - The pollutants produced in the atmosphere after the primary pollutant’s chemical reaction with natural compounds are called secondary pollutants. Ozone (o3) in gases is considered a secondary pollutant. Ozone reacts with biological tissue in the upper respiratory system and causes adverse effects.
How Physical Activity Is Affected In Polluted Air?
The habit of exercise is beneficial for overall health. Increased physical activity can also lead to exposure to air pollutants. Air pollutants refer to dust particles which are harmful to health. The most affected is cardiovascular health due to inhaled pollutants. There is a cardiovascular risk from exercising in polluted air. The air pollutants are inhaled by humans and circulated in the blood, which affects health. This process is called diffusion of air pollutants into the blood. The pollutants in the blood cause oxidative stress and inflammation, which can increase blood pressure.
The following are the health risk of polluted air:
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High blood pressure.
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Impaired vascular function (poor circulation of the blood).
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It also affects autonomic balance. The autonomic balance refers to the coordination of the nervous system.
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Impaired exercise.
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Heart stroke.
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Impaired function of the heart.
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The habit of mouth breathing.
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Systemic oxidative stress.
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Systemic inflammation.
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Thrombosis and coagulation.
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Myocardial infarction (heart muscle is damaged in a condition known as myocardial infarction).
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Atherosclerosis (a condition in which the deposition of cholesterol takes place in the artery, which causes obstruction in blood flow).
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Bronchitis (a condition in which the inflammation of the bronchi takes place).
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Asthma (a condition in which patients face difficulty in breathing).
What Are the Cardiovascular Risk Of Exercise In Polluted Air?
The cardiovascular system is directly linked to air pollution. The cardiovascular risk occurs during exercising in polluted air. The biological response to air pollution and exaggerated risk for cardiovascular diseases.
The cardiovascular actions of pollutant air exposure are as follows:-
Physiological Changes In Air Pollution - The physiological changes are affected by air pollutants.
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Cardiovascular actions can be affected during exercise in polluted air.
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Vigorous exercise in polluted air can impair nasal passage.
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The pathway of breathing from nose to mouth during exercise can increase the deposition of particulate matter in the lungs.
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Deep and rapid breathing during exercise causes an increased breathing rate.
These biological changes make the person sensitive even in the ambient outdoor environment.
- Lung Oxidative Stress and Inflammation - Exposure to ozone among healthy individuals causes inflammation in the airways after moderate exercise. The inhalation of air pollutants raises the biological markers of inflammation in the lungs. These markers indicate that air pollutants increase oxidative stress and inflammation which is the result of exaggerated responses. The inhalation of ultrafine particles can also cause damage to genetic materials.
- Blood Pressure - The decrease in blood pressure was observed after inhalation of carbon monoxide (air pollutants) to the patient having cardiovascular risks.
- Impaired Blood Supply - The blood supply is affected in a young person during exercise in air pollution. The blood flow from the artery and supply of blood to the lungs is impaired due to the stiffness of the artery in the pathway. These studies suggest that exposure to particulate matter can trigger the construction and dilatation of the artery in a healthy person. These sequences can cause increased heart rate and heart failure.
- Heart Rate Variability - Studies observed the variability of heart rate and exposure to air pollutants during exercise. The adverse changes in heart rate variability have been reported by these studies during an exercise in polluted air. The acute balance of the body during exercise in air pollution has been noticed in healthy people and cardiac patients.
- Arrhythmias - The condition in which the person suffers from an irregular rhythm of the heartbeat. Exposure to carbon monoxide does not produce an arrhythmic effect during exercise in healthy volunteers and patients with cardiovascular risk. The higher dose of carbon monoxide before exercise has been associated with an increase in arrhythmias in cardiovascular patients.
- Angina and Myocardial Ischemia- The condition in which a person suffers from shortness of breath and chest discomfort is called angina. Myocardial ischemia refers to the condition when cardiac disease has weakened the heart muscles. Exposure to carbon monoxide before an exercise did not alter the heartbeat, but during an exercise in polluted air, it affects the heartbeat. The inhalation of carbon monoxide affects the rhythm of heart beat in patients with cardiovascular risk. Some studies observed that the inhalation of carbon monoxide fastens angina onset and time to the development of ischemic heart changes in the patient with cardiovascular risk. Particulate matter can also trigger changes in the heart rhythm or heartbeat in the patient with severe cardiovascular risk. However, there is inadequate evidence to draw a conclusion that the healthy individual is also affected by inhalation of carbon monoxide.
Conclusion
In summary, inhalation of carbon monoxide and particulate matter affects the heart’s functions. The long-term benefit of cardiovascular health is questionable. The triggering factor and risks outweigh the benefit of regular exercise. The European studies concluded that the mortality outweighs the benefit of aerobic exercise due to an increase in air pollution inhalation. Some measures, like wearing a mask, should be followed by patients with cardiovascular risks. The patient should be informed about the feasible strategies to lessen the cardiovascular risk due to the degree of air pollution exposure. However, regular aerobic exercise improves overall health and reduces cardiovascular risk in the long term.
