Addiction

• The primary culprit in the negative reactions to quitting smoking is the addicting substance nicotine found in cigarettes. It is responsible for the withdrawal symptoms that occur directly after quitting, as the body tries to compensate for its sudden removal from the system. In addition, coupled with the body's physical reaction is the emotional toll taken by quitting a long-term habit, which may require a serious reorganizing of day to day activity.
  
  

Short-Term Reactions

• Nicotine generally stays in the system three or four days after the last cigarette, so the highest intensity of withdrawal symptoms will occur when the last of the nicotine has departed. Among these symptoms are headaches, anger, depression, nervousness, or dizziness. However, in this same time frame the body's heart rate will lower, its carbon monoxide levels will drop, and energy will increase.
  
  

Long-Term Reactions

• As time goes on, the benefits of quitting smoking begin to far outweigh the negatives. Lungs will strengthen, leading to less coughing and chance of infection. The body will be less prone to a heart attack, as well as less likely to develop any of the plethora of cancers smoking can help cause. Finally, quitting can add time to one's lifespan, no matter when the decision was made to quit.