Damages Heart
Cigarettes are often blamed for causing lung cancer or other breathing disorders, but about 20 percent of all deaths from heart disease in the United States are also the result of smoking. This major cause of heart disease is triggered by the nicotine present in cigarettes. Nicotine causes heart disease by decreasing oxygen to the heart, increasing blood pressure and heart rate, increasing blood clotting and damaging cells that line coronary arteries and other blood vessels. Nicotine narrows the blood vessels, increasing the heart rate and putting more strain on the heart. It narrows the arteries to make them vulnerable to atherosclerosis, or hardening of the arteries, which can led to heart attack or stroke.
Insulin
In landmark research funded by the National Institutes of Health, it was learned that nicotine promotes insulin resistance that leads to prediabetes, a major risk factor for cardiovascular disease. Even though smoking can cause weight loss, which can protect against heart disease, the nicotine in cigarettes offsets that. The insulin resistance in smokers causes their hormone insulin to work improperly. Their blood glucose levels become higher than normal.
Blood Flow
Earlier studies have shown that nicotine reduces the blood flow in the arterial lining. This damage causes the build-up of plaque inside the arteries that can lead to atherosclerosis. It is believed that the body's exposure to nicotine causes oxidative stress from free radicals. The nicotine in cigarettes also results in high levels of a stress hormone, called cortisol, according to other studies. Excess cortisol is known to induce insulin resistance. Researchers have been able to reverse the harmful effects of nicotine in mice by treating them with mecamylamine, a drug that blocks the action of nicotine. It led to the reduction of cortisol levels, and in the future anti-nicotine drugs may be developed to improve the condition of people with insulin resistance.
Therapies
It is clear from many studies that nicotine directly increases the risk of heart disease. There may also be dangers in nicotine replacement therapies, but those threats would subside if the therapy helps smokers quit. In the meantime, it is far more important for smokers to quit smoking. They won't just reduce their risk of lung cancer and other cancers, but they will also reduce the risk of heat disease, heart attack and high blood pressure by taking nicotine out of their system.
