When a person quits smoking, his body begins to heal itself and his heart rate settles within the first 20 minutes after the last cigarette is finished, according to Healthline. The benefits continue as the person's blood pressure, circulation and lung functioning improve during the first month.
Many of the disadvantages and health risks associated with smoking diminish rapidly after a person chooses to quit smoking, explains Healthline. For example, the body is able to begin repairing its nerve endings within the first 48 hours, which helps to restore the senses of smell and taste to normal levels. The risk of heart attack is also reduced soon after cigarettes are removed as a habit. There is a period of time during the first week when people are likely to experience unpleasant side effects related to nicotine withdrawal, such as irritability, nausea and headaches, but these clear up once the nicotine has completely left the body.
Towards the end of the first month after quitting smoking, patients are likely to feel an increase in their energy levels and physical stamina. This is also the point when the lung tissue begins to repair itself, remedying much of the coughing and breathing complications that are associated with long-term smoking. The larger milestones occur at one and five years, when a person is 50 percent less likely to experience a heart attack and the risk of stroke is significantly diminished, notes Healthline. After 10 years, a person's risk of contracting several forms of cancer related to smoking, such as lung and throat cancer, is greatly reduced.