SUNDAY, Feb. 27, 2005 (HealthDay News) -- Eating with friends in a smoke-filled restaurant or partying at a smoky bar, nonsmokers can look pretty happy on the outside.
But on the inside, experts say, potentially lethal damage to hearts, lungs and arteries is already under way.
"In terms of lung cancer, secondhand smoke is thought to cause the deaths of 3,000 Americans every year, and the number for cardiovascular deaths is even higher, between 37,000 to 50,000 deaths per year," said Dr. Norman Edelman, consultant for scientific affairs at the American Lung Association.
The tars, nicotine and carbon monoxide in cigarette smoke pose a triple threat to lung tissue and blood vessels, upping cancer risk, constricting airways and arteries and robbing blood of precious oxygen.
"By speeding up the heart and squeezing down the vessels, it just puts a big burden on your heart," Edelman said. In fact, a British study published in June 2004 in the journal Thorax found that men exposed to secondhand smoke over long periods of time faced a 50 percent higher risk of coronary heart disease than men without such exposures.
Thomas Glynn, director of cancer science and trends at the American Cancer Society, told HealthDay the findings "should reinforce your determination not to be exposed to secondhand smoke. It can't be dismissed as something that is not harmful."
Unfortunately, far too many Americans continue to disregard the threat of passive smoking, said Dr. Richard Stein, a spokesman for the American Heart Association and a cardiologist at Beth Israel Hospital in New York City.
"This isn't just some feel-good environmentalist issue," he said. "This is everybody's issue."
He pointed to one recent study that tracked risk for heart attacks in both smokers and nonsmokers. The study found that heart attack risks for individuals at the highest level of secondhand smoke exposure were "two and a half times higher than [those] in the low range."
"That's a major change in risk -- as much as having a risk factor like high blood pressure," Stein said.
Some experts even wonder if passive smoking might be worse than dragging directly off a cigarette. "There's always an ongoing discussion as to the difference between the two because some of the secondhand smoke comes directly from the burning tip of the cigarette," Edelman said.
Whatever its potency, tobacco smoke remains extremely harmful even when sourced secondhand. "It has three major toxic effects," Edelman said. "One are the tars -- they coat your airways and if they do it long enough they are going to cause cancer. The second is nicotine, it's a vasoconstrictor -- it squeezes your blood vessels down."
Vasoconstriction can go unnoticed in healthy people, but for others it brings immediate symptoms. People with peripheral vascular disease, who suffer from poor blood flow in the extremities, are especially at risk. "If they inhale smoke, their legs will pain immediately because they've already got compromised vessels," Edelman said.
Then there's carbon monoxide. "It essentially robs your blood of oxygen by as much as 10 to 12 percent," Edelman said.
Again, that's not enough to bother most healthy adults, but for people with cardiovascular disease it can be a real threat. "Also, if you're a pregnant woman, and your baby needs the maximum delivery of oxygen to develop normally in the uterus, it can be detrimental, too," Edelman said.
Based on the accumulated evidence, three major health groups -- the American Cancer Society, the American Heart Association and the American Lung Association -- have long called for bans on smoking in workplaces, including bars and restaurants.
"Understand, too, that when people argue legislatively against passive smoking, it's not about simply trying to make it tougher for smokers so that they have to give up smoking," Stein said. "This is a legitimate health issue, in terms of protecting the air quality for everybody."
Although some 1,700 U.S. cities already have put some sort of comprehensive smoking ban in place, initiatives to curb public puffing still meet strong resistance, especially from restaurant and bar owners worried about their bottom lines.
"Yes, that argument was put forth here in New York City, where we now have a law banning smoking in bars and restaurants," Stein said. "Basically though, the major of industry people here have stopped carping because they've found that business isn't down at all."
Public smoking bans may even be saving lives, one study suggests.
Reporting last year in the British Medical Journal, researchers reviewed hospital records from the city of Helena, Mont., where a public smoking ban enacted in April 2002 was overturned by the following December. However, in those six smoke-free months, the researchers found that the number of patients admitted to Helena hospitals with heart attacks fell by 40 percent.
More information
To learn more about the dangers of secondhand smoke, visit the American Lung Association.