Nicotine and other substances in tobacco smoke immediately affect the cardiovascular systems of smokers and those who inhale the secondhand smoke. Active cigarette smoking elevates the heart rate and blood pressure for up to 20 minutes after tobacco use, says the American Lung Association.

Similar effects occur when smoke is inhaled passively. According to the U.S.Centers for Disease Control and Prevention, or CDC, the widespread heart health problems created by long-term damage contribute to the deaths of 126,000 people annually, as of 2008.

Atherosclerosis

Cigarette smoking increases blood cholesterol levels, causing a buildup of arterial plaque that narrows the blood vessels over time. The U.S. Surgeon General’s 2010 report on tobacco smoke and disease notes that this reduces circulation to bring about health problems in many areas of the body.

One such health problem is peripheral venous disease, in which reduced blood flow does not support cell growth in the legs and skin. Tissue death may require amputation. Vascular damage from tobacco use can also give rise to abdominal aortic aneurysm, an arterial bulge that may rupture and cause death.

Blood Clots

Less room for blood to flow within the blood vessels that lead to the heart and brain leaves tobacco users more vulnerable to heart attack and stroke. Cigarette smoking and secondhand smoke contact make blood platelets sticky and prone to clotting.

As the American Heart Association, or AHA, explains, blood clots in the narrowed vascular space can easily cause partial or total obstructions. Interrupted blood flow to the heart or brain may result in serious health problems including arrhythmias, paralysis or memory loss. Completely blocked blood flow can cause death in a matter of seconds

Low Blood Oxygen

Another possible contingency of tobacco use is pulmonary hypertension, or high blood pressure between the lungs and heart. The AHA describes this health problem as the reduced capacity of cardiopulmonary blood vessels to exchange oxygen and carbon dioxide, a vital metabolic function.

The CDC reports that oxygen levels are already compromised in smokers, who ingest carbon monoxide and other gases in cigarette smoke. These toxins displace part of the normal load of oxygen that the lungs transfer to the bloodstream. The heart then circulates them to the rest of the body. Pulmonary hypertension further reduces oxygen levels.

MayoClinic.com reports that a heart damaged by cigarette smoking may not be able to pump more blood to get a greater volume of oxygen to the cells. A resulting condition called congestive heart failure can severely restrict tobacco users’ tolerance for exercise, making physical activity difficult or raising the risk for heart attack and stroke due to exertion.