This study briefly exposed people to low levels of common pollutants and measured their cardiovascular and cardiorespiratory responses. Forty healthy non-smokers (21 women, 19 men) whose average age was 35 participated in the experiment. The researchers exposed the participants to secondhand cigarette smoke, wood smoke or cooking oil smoke in separate trials as they sat in a 10-by-10-foot environmental chamber. The researchers cleared the air in the chamber after each trial.
They measured respiratory and cardiovascular function, including heart rate variability, breathing and blood pressure. These measures, in turn, gave researchers a picture of how the heart, circulatory and respiratory systems were reacting to the pollutants.
The study found that, particularly among men, exposure to smoke changed breathing patterns, raised blood pressure oscillations in peripheral arteries and shifted control of heart rate toward sympathetic domination. The sympathetic nervous system becomes active during times of stress, but can cause harm to the heart and blood vessels if activated too often or too long.
Women did not have a strong sympathetic response to the pollutants, a healthier response in the face of frequent exposure. That men would respond differently is not a surprise: women tend to have stronger parasympathetic responses, which are more protective of the cardiovascular system, Ms. Evans said.
These results confirm results from earlier studies, but with exposures that were at lower levels and for shorter lengths of time. The study also extended the findings in several ways, including finding that men and women respond differently.
"I was surprised we got statistically significant results with this low level of exposure," Ms Evans said. "If we can detect these effects with smaller exposures, then the public health hazard from cigarettes and other parti
|Contact: Donna Krupa|
American Physiological Society