Smoking can alter the system of automatic correction of blood pressure

According to researchers, smokers are more likely to develop hypertension. An overactive response to normal blood pressure reductions may explain why.

"The human body has a buffer system that continuously monitors and maintains healthy blood pressure," said Lawrence Sinoway, director of the Penn State Clinical and Translational Science Institute. "If the blood pressure goes down, a reaction called Muscle Friendly Nerve Activity (NSA) is triggered to bring the blood pressure back to a normal level."

An additional system, called baroreflex, helps correct if the blood pressure is too high, he added.

According to Sinoway, the study showed that after an MSNA explosion, the increase in blood pressure in a chronic smoker was about twice as high as in a non-smoker, pushing blood pressure to unhealthy levels. The researchers suspect that the weakening of the baroreflex is the cause.

"When the sympathetic nervous system goes off, as with NASM, your blood pressure goes up, and then a series of factors curb this increase in order to try to mitigate it," Sinoway said. "We think that in smokers, this depreciation – the baroreflex – is impaired."

Jian Cui, badociate professor of medicine, said the findings suggest that this deficiency could be related to hypertension.

"The larger increase in blood pressure in response to NASM could contribute to a higher resting blood pressure level in smokers without hypertension," Cui said. "It is possible that this higher response to NASM could also contribute to the possible development of hypertension."

The researchers said that although previous research has revealed a link between chronic smokers and higher levels of NASM outbreaks, less was known about what had become of blood pressure after these explosions. In addition, Sinoway stated that other studies were looking at the effects of acute smoking – a single exposure to cigarette smoke – on non-smokers rather than the usual smokers.

For this study, researchers recruited 60 participants – 18 smokers and 42 non-smokers. None of the participants had hypertension. Smokers reported smoking an average of 17 cigarettes a day for about 13 years.

To measure the NASM, the researchers inserted an electrode into the peroneal nerve located under the patella of each participant. In addition, they measured heart rate, diastolic and systolic blood pressure, and mean arterial pressure at the level of the brachial artery in the upper arm.

After badyzing the data, the researchers found no difference in systolic blood pressure between smokers and non-smokers. However, diastolic blood pressure, mean arterial pressure, and heart rate were significantly higher in smokers. Smokers also had higher levels of NASM. In addition, resting heart rate was significantly higher in smokers.

Cui said the results, recently published in the US Journal of Physiology – Regulatory, Integrative and Comparative Physiology, give further evidence of the harmfulness of smoking.

"Our study reveals another mechanism by which habitual smoking can contribute to the development of hypertension," Cui said. "Further studies are needed to determine if smoking cessation can decrease this accentuated response."

In the future, Sinoway said other researchers and he would continue to study the link between smoking and hypertension.

"We hope to better understand how much cigarette consumption contributes to the development of hypertension," Sinoway said. "Then we can try to understand if there are things we can do to intervene and prevent chronic smokers from developing this disease."