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HEART
May 12, 2009
Brief Exposure, Big Response
Just 10 minutes is all it takes for air pollution or secondhand smoke to begin to affect your heart and cardiovascular system.
Inhaling secondhand smoke from cigarettes, cooking oil, and burning wood may have a significant effect on cardiovascular function in as little as 10 minutes, according to researchers at the University of Kentucky, Lexington. The study expands on previous research indicating that increased risk of heart attacks and death has accompanied an increase in air pollution in recent years.
Interestingly, men and women showed different cardiovascular responses to the smoke. Men showed a more marked increase in sympathetic response in heart rate — the sympathetic nervous system controls the "fight or flight" response, readying the body for energy expense. Evans says that if this system is activated too frequently or for an extended period of time, it can actually cause damage to the heart and blood vessels. Men's blood pressure was also raised in peripheral arteries and their breathing changed.
Women, in contrast, did now show the robust sympathetic response that men did. This makes sense, Evans says, since women typically have stronger responses from the parasympathetic nervous system, which ultimately acts to protect the cardiovascular system.
The study's findings are particularly striking since they support the results of earlier studies while using an even shorter period of smoke exposure than previous research.
"I was surprised we got statistically significant results with this low level of exposure," Evans said of her team's results. "If we can detect these effects with smaller exposures, then the public health hazard from cigarettes and other particulate exposures may have been underestimated."
The study was presented at the 122nd annual conference of The American Physiological Society.
The research team, led by Joyce McClendon Evans, determined the effect of very short exposure to tobacco, cooking oil, or wood smoke in 21 women and 19 men. Participants' mean age was 35 and all were non-smokers. Each person sat in a 10'x10' room during the 10 minute exposure to one of the three types of smoke.Interestingly, men and women showed different cardiovascular responses to the smoke.
Interestingly, men and women showed different cardiovascular responses to the smoke. Men showed a more marked increase in sympathetic response in heart rate — the sympathetic nervous system controls the "fight or flight" response, readying the body for energy expense. Evans says that if this system is activated too frequently or for an extended period of time, it can actually cause damage to the heart and blood vessels. Men's blood pressure was also raised in peripheral arteries and their breathing changed.
Women, in contrast, did now show the robust sympathetic response that men did. This makes sense, Evans says, since women typically have stronger responses from the parasympathetic nervous system, which ultimately acts to protect the cardiovascular system.
The study's findings are particularly striking since they support the results of earlier studies while using an even shorter period of smoke exposure than previous research.
"I was surprised we got statistically significant results with this low level of exposure," Evans said of her team's results. "If we can detect these effects with smaller exposures, then the public health hazard from cigarettes and other particulate exposures may have been underestimated."
The study was presented at the 122nd annual conference of The American Physiological Society.
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