What are the immediate effects of smoking cessation?

Immediate Effects of Smoking Cessation

Smoking cessation produces almost immediate health benefits, with some advantages occurring within hours to days of quitting, including reduced blood carbon monoxide levels, decreased respiratory symptoms such as cough and shortness of breath, and improved lung function. 1

Cardiovascular Benefits

The cardiovascular system responds rapidly to smoking cessation:

• Blood carbon monoxide levels normalize within hours of the last cigarette 1
• Cardiovascular risk begins declining immediately, with stroke risk decreasing by 50% within the first year of cessation 2
• After a myocardial infarction, smoking cessation is the single most effective preventive measure, with significant morbidity reductions reported within the first 6 months 1
• The mortality benefit for post-MI patients who quit is substantial (OR 0.64,95% CI 0.58-0.71) compared to continued smokers 1

Respiratory Improvements

Pulmonary function shows early positive changes:

• Decreased irritative respiratory symptoms including cough and shortness of breath occur within days to weeks 1
• Improved lung function is measurable in the immediate period following cessation 1
• These improvements are particularly relevant for patients with COPD, where cessation is the only evidence-based intervention that improves prognosis by mitigating lung function decline 1

Nicotine Withdrawal Syndrome

Withdrawal symptoms typically begin within 24 hours of the last cigarette, peak acutely for 3-4 days, and usually extend to 3-4 weeks 1:

• Cigarette craving peaks in the first week and then diminishes, though it may persist for months or years in some individuals 1
• Common withdrawal symptoms include anxiety, depression, irritability, and difficulty concentrating 1
• Weight gain occurs in >75% of quitters, with mean gains of 2.8 kg in males and 3.8 kg in females, though this does not diminish the substantial cardiovascular benefit of cessation 1

Mental Health Effects

Contrary to common perception that smoking helps manage stress:

• Smoking cessation is associated with improvements rather than worsening of mental health symptoms 3
• Anxiety symptoms improve (SMD -0.28,95% CI -0.43 to -0.13) 3
• Depression symptoms improve (SMD -0.30,95% CI -0.39 to -0.21) 3
• Stress levels decrease in successful quitters, who become indistinguishable from stable nonsmokers in stress levels 4
• These improvements occur even in populations with pre-existing mental health conditions 3

Metabolic Changes

For patients with diabetes:

• Smoking cessation is associated with amelioration of metabolic parameters within 1 year 1
• Blood pressure and albuminuria are reduced at 1 year post-cessation 1

Cancer Treatment Considerations

For patients with cancer:

• Recent quitters (those who quit near diagnosis) have survival outcomes intermediate between never-smokers and current-smokers, suggesting measurable benefit even with recent cessation 1
• Symptom burden during chemotherapy and/or radiation therapy is reduced in those who quit 1
• Drug metabolism may be affected, particularly for erlotinib and irinotecan, potentially requiring dose adjustments 1

Important Caveats

• The health benefits of quitting undoubtedly outweigh any potential side-effects associated with nicotine withdrawal 5
• Pharmacological treatment of withdrawal symptoms during the immediate cessation period may improve patient comfort and promote long-term abstinence 1
• Physician's firm and explicit advice to stop smoking completely is the most important factor in getting the cessation process started, with momentum particularly strong at the time of diagnosing cardiovascular disease 1