How does smoking cause hypertension?

From the Guidelines

Smoking causes hypertension through several mechanisms that affect the cardiovascular system, and quitting smoking is one of the most effective lifestyle modifications for blood pressure control, often resulting in greater improvements than some blood pressure medications alone. When a person smokes, nicotine immediately triggers the release of catecholamines like adrenaline, causing a rapid increase in blood pressure and heart rate, as noted in the 2007 guidelines for the management of arterial hypertension 1. Additionally, smoking damages the inner lining of blood vessels (endothelium), reducing their ability to dilate properly. Carbon monoxide from cigarette smoke reduces oxygen in the blood, forcing the heart to work harder. Over time, smoking leads to arterial stiffness and chronic inflammation, both of which contribute to sustained high blood pressure. Cigarette smoke also contains thousands of chemicals that increase oxidative stress, further damaging blood vessels. The combination of these effects results in both immediate blood pressure spikes after smoking and long-term hypertension with continued use.

Key Mechanisms

• Stimulation of the sympathetic nervous system at central level and at nerve endings, leading to an increase in plasma catecholamines parallel to the blood pressure increase, as described in the 2007 guidelines for the management of arterial hypertension 1
• Damage to the inner lining of blood vessels (endothelium), reducing their ability to dilate properly
• Reduction of oxygen in the blood due to carbon monoxide from cigarette smoke, forcing the heart to work harder
• Arterial stiffness and chronic inflammation contributing to sustained high blood pressure
• Increase in oxidative stress due to thousands of chemicals in cigarette smoke, further damaging blood vessels

Benefits of Quitting

• Significant improvement in blood pressure levels, with benefits beginning within hours of cessation and substantial improvements seen within weeks to months
• Reduction in cardiovascular risk, including stroke, myocardial infarction, and peripheral vascular disease, as noted in the 2013 ESH/ESC guidelines for the management of arterial hypertension 1
• Improvement in overall health and quality of life, with those who quit smoking before middle age typically having a life expectancy that is not different from that of lifelong non-smokers, as mentioned in the 2007 guidelines for the management of arterial hypertension 1

Recommendations

• Smoking cessation should be strongly advised for all smokers, particularly those with hypertension, as it is one of the most effective lifestyle modifications for blood pressure control, often resulting in greater improvements than some blood pressure medications alone
• Lifestyle modifications, including weight reduction, moderation of alcohol consumption, physical activity, reduction of salt intake, and increase in fruit and vegetable intake, should be instituted in all patients with hypertension, as recommended in the 2007 guidelines for the management of arterial hypertension 1
• Nicotine replacement therapy, bupropion, or varenicline should be considered for smoking cessation, as noted in the 2013 ESH/ESC guidelines for the management of arterial hypertension 1

From the Research

Mechanisms of Smoking-Induced Hypertension

• Smoking increases the risk of hypertension by 2 to 3 times, as stated in the study 2.
• The increased risk from smoking declines rapidly on quitting, within 2-3 years, as noted in the study 2.
• Smoking increases the risks of vascular damage by:
  • Increasing sympathetic tone
  • Increasing platelet stickiness and reactivity
  • Increasing free radical production
  • Damaging the endothelium
  • Causing surges in arterial pressure, as mentioned in the study 2.
• Nicotine and carbon monoxide in cigarette smoke play major roles in the cardiovascular effects of smoking, as discussed in the study 3.
• These substances adversely alter the myocardial oxygen supply/demand ratio and produce endothelial injury, leading to the development of atherosclerotic plaque, as explained in the study 3.

Effects of Smoking on Cardiovascular Health

• Smoking is the main risk factor for atherosclerotic cardiovascular disease, as stated in the study 4.
• Smoking causes oxidative stress, endangers the lining of the arteries, and accelerates the accumulation of fatty plaque in the blood vessels, as mentioned in the study 4.
• Smoking increases the risk of sudden thrombotic events, inflammatory alterations, and low-density lipoprotein oxidation, as noted in the study 4.
• The risks associated with smoking increase when combined with diabetes, hypertension, high cholesterol, and glucose intolerance, as discussed in the study 4.

Synergistic Effect of Smoking and Hypertension

• Smoking exacerbates the effect of blood pressure on the risk of cardiovascular and all-cause mortality among hypertensive patients, as found in the study 5.
• A dose-response association between pack-years smoked and risk of cardiovascular disease and all-cause mortality was observed among different blood pressure groups, as mentioned in the study 5.
• Smoking cessation is an essential component for preventing deaths related to smoking, in addition to hypertension management, as recommended in the study 5.

Molecular Mechanisms of Smoking-Induced Vascular Alterations

• Cigarette smoking causes injury to the vascular endothelium, produces superoxide anions, reduces production and bioavailability of nitric oxide, and increases production and release of endothelin, as explained in the study 6.
• Smoking causes endothelial dysfunction, thrombosis, atherosclerosis, infarction, coronary artery disease, stroke, and death, as discussed in the study 6.