Nicotine and Coronary Heart Disease: How are They Related?
Cigarette smoking has been controversial for years. People have been made aware of the harmful effects smoking has on their body through various campaigns. It has been a widely known fact that smoking is a significant risk factor for many lifestyle diseases including chronic obstructive pulmonary disease (COPD), cancer, and heart disease.
According to the World Health Organization (WHO), ischemic heart disease was the number one cause of mortality (death) around the world in 2015. Together with stroke, they caused approximately 15 million deaths in 2015 alone. For 15 years, they remain as the leading causes of death worldwide.
What’s in a Cigarette?
A tiny cigarette stick is composed of a paper wrapping, a filter, tobacco, and more than 7000 harmful chemicals, 70 of which are identified as carcinogenic (cancer-causing). One of the most harmful chemical in cigarettes and most prominent, causing addiction and many other physiologic effects, is nicotine.
Immediately after consuming a cigarette, nicotine induces an increase in your heart rate and blood pressure. This happens because nicotine activates your body’s sympathetic response.
Nicotine stimulates the adrenal medulla of your adrenal glands (located at the top of your kidneys) to release epinephrine and norepinephrine (the fight-or-flight hormone). The release of these two hormones results in an increased blood pressure, a faster heart rate, and stronger heart contractions.
Your blood vessels also constrict, or decrease in diameter, increasing the resistance and contributing to a further increase in your blood pressure. For these reasons, it is essential to monitor your health by taking your blood pressure manually, especially if you smoke and have an existing condition like heart disease or diabetes.
Coronary heart disease (CHD), also known as coronary artery disease (CAD) and ischemic heart disease, is characterized by narrowing of the coronary arteries due to piling up of fatty plaque deposits that harden the walls of your arteries.
Your heart pumps out blood to supply all the organs in your body. Likewise, your heart itself also needs oxygenated blood to function just like any other body part. The coronary arteries are small blood vessels branching out from the base of your aorta that supply oxygen-rich blood to your heart muscles (myocardium).
Some non-modifiable factors can predispose you to have CHD such as your family history, sex (more common in men), and age (older people are more likely to have CHD). Having underlying health conditions such as a high level of cholesterol and blood sugar as well as being hypertensive and overweight can also increase your likelihood of having the disease.
Lifestyle factors such as physical inactivity and cigarette smoking also increase your risk of developing coronary heart disease. In fact, cigarette smoking cessation has been established as the most important way to prevent coronary heart disease.
Nicotine and Coronary Heart Disease
Nicotine is a robust sympathomimetic substance, which means that it acts as a stimulant that targets your heart and blood vessels. Among the effects of nicotine secondary to the stimulation of the sympathetic nervous system are vasoconstriction (smaller diameter of the blood vessels), rapid heart rate, stronger heart contractions, and an increase in blood pressure.
The increase in blood pressure and faster heart rate will result in an increase in your heart’s demand for oxygen and nutrients. Since nicotine increases the workload of your heart, it will require more energy (generated with the aid of oxygen through aerobic metabolism) and nutrients to sustain the demand.
The vasoconstriction effect of nicotine also affects your coronary arteries. When your coronary arteries constrict, the supply of oxygenated blood and nutrients to the heart muscles are reduced. Your arteries can also become damaged and occluded.
Damage to blood vessels initiates inflammation. Plaques build up in the linings of the damaged arteries, causing further narrowing of the blood vessels. This condition is known as atherosclerosis.
Chronic exposure to nicotine means that these physiologic processes repeatedly happen inside your body. In the long-term, these might progress to myocardial ischemia and myocardial infarction.
The term “myocardial” refers to the heart muscles (myocardium) while “ischemia” means that there is an inadequate blood supply to the tissue. On the other hand, “infarction” is a grave condition which means that there is already tissue death secondary to a blocked artery or blood supply.
When these happen, your heart will be ineffective in its function of pumping blood. Diminished blood supply to the heart can also result in heart failure and abnormal electrical heart conduction (arrhythmia). If the infarct is severe, you could suffer from angina (chest pain) and even heart attack.
Campaigns are being done to educate and encourage people to quit smoking. Since cigarette smoking is addictive, a lot of people struggle to cope. If you are among them, talk to your healthcare provider regarding the ways on how to stop this unhealthy habit.
by Joe Fleming