Your heart is one of the most important parts of the body to be affected by the stimulant nicotine. Your heart rate can increase as part of a craving or during use, often while you are smoking. Your body reacts to the drug being introduced into your system by pumping up your heart rate. As you may know, your heart needs to keep a certain rhythm to be healthy. Speeding it up during exercise is a good workout for your heart, but it is unhealthy for your heart rate to increase very much when you are inactive. And that is exactly the state of most people while they are smoking. They are simply relaxing, but their heart rate is faster than it should be.
This can cause long-term heart problems, which include cardiac infarction, heart disease and more. The longer you smoke, the more stress you are putting on your heart and the greater your risk of a heart problem.
Nicotine also stimulates your respiratory and vascular system. People who are craving nicotine may have a faster breathing rate. Their anxiousness and nervousness caused by the craving will make them breath irregularly. This limits their physical abilities and in some ways cripples them, making them helpless against the physical effects of their addiction.
An increase of blood pressure, which is standard for nicotine users, is also dangerous. This puts your heart at risk and creates an unhealthy environment for many of your bodily systems.
It is important to understand that nicotine is both a stimulant and a sedative. While it creates stimulating effects, it also relaxes the body and creates a state of gentle euphoria. This is part of what makes it so addictive. That buzz that many smokers feel makes the other effects feel not as strong. The higher the concentrations of nicotine are, the greater the sense of euphoria will be.
Nicotine also activates the portion of the bran that rewards the body. This reward center is responsible for a lot of the motivation people feel. Regular nicotine users feel like they need that cigarette as a reward for getting through the day, surviving a few hours of work or for passing a test. They will say that the nicotine relaxes them, though in many ways it does the exact opposite. What it actually does it make them feel like they are being treated or rewarded by having that cigarette.
This causes severe addiction, and any of the people who try to quit do not succeed because of it.