Can On-the-Job Air Pollution Hurt the Heart?
Aug. 27, 2001 -- Pollution is bad for the lungs. It also can harm the hearts of sick, elderly people. Now, Harvard researchers say their new study is the first to show that high levels of air pollutants can affect the hearts of young, healthy people as well.
Researchers at the Harvard School of Public Health studied 40 men between the ages of 19 and 59 who worked as boilermakers in Boston. On the job, these men were exposed to many air particles and metal fumes that are similar to those in the general environment, but at much higher concentrations. Among the most toxic pollutants are particles called PM2.5 that, due to their tiny size, penetrate deep into the lungs and tend to stay there.
The researchers measured the workers' exposure to PM 2.5 throughout the day, as well as how much their heart rates varied.
Generally, a healthy person has a heart that will beat at all sorts of different rates during a typical day, lead author Shannon Magari, ScD, MPH, tells WebMD. The body has different needs for blood circulation all day long, and the healthy heart is able to adjust to the demand quickly. However, hearts that seem to have trouble adjusting to daily demands have been linked to higher risk of heart attacks as well as death.
Magari, a postdoctoral research fellow at the Harvard School of Public Health, and colleagues found that the workers' hearts were not as adaptable while they were at work. And it seemed that the greater the exposure to PM 2.5, the less their hearts were able to keep up.
"This is important because it's the first study that we are aware of that looked at heart rhythm changes in young, healthy workers," says Magari. "Most of the work to date has been with elderly, [and sick] populations." She says that the changes seen in her study were not as dramatic as those recorded in earlier studies on elderly people, but they were similar and hinted at the risk of the same sorts of health problems.
Despite the findings, Magari says people shouldn't panic. "It is very important to stress that these are small, subtle changes that have no symptoms associated with them," she says, noting that the workers didn't feel anything. "But again, it's the first time this change has been demonstrated in a young, healthy population."
Others are not that impressed. "I think it is a very small study from which we can conclude very little for the general population," says Laurence Sperling, MD. He is the medical director of preventive cardiology at the Emory Clinic in Atlanta, who reviewed the study for WebMD.
Additionally, Sperling says that other factors that the researchers didn't or couldn't measure could have accounted for the drop in heart rate variability. "I'd summarize by saying it's an interesting little study [but] I think we'd have to see a lot more information before we can really conclude anything on a larger scale."
Magari agrees more studies are needed, especially to see what these changes mean for these particular workers in the long run. Future research also needs to assess the risk to the general public, where most people have a much lower exposure to air pollution.