A recent study found that brief exposure to marijuana smoke raises the risk of cardiovascular as much as second-hand exposure to smoking does, but the detrimental effects last three times longer.
And it doesn’t take much for the negative health impacts to occur. A minute of second hand smoke from pot is enough to boost heart disease risk, UC San Francisco researchers found.
Study authors based their conclusion on data gathered from laboratory animals. The team found that marijuana smoke impedes blood flow and prevents blood vessels from widening thus boosting the risk of a heart attack, stroke, and other cardiovascular conditions.
Senior author of the analysis Matthew Springer explained that arteries can naturally sense when blood flow increases, so they dilate to allow blood to pass. But in the presence of pot smoke, they can no longer do that.
Past experiments conducted by Prof. Springer’s team found that just one minute of exposure to marijuana smoke lowered blood vessels’ ability to dilate. The latest study assessed the level of vasodilation also known as flow-mediated dilation (FMD) in rats in the presence of pot and tobacco smoke.
Experiments showed that lab animals exposed to marijuana smoke saw their FMD sink by more than half, an effect similar to that triggered by tobacco smoke. But unlike in tobacco smoke, the effect persisted three times longer in marijuana smoke.
For instance, rats exposed to tobacco smoke regained their natural FMD levels after half an hour, while rats exposed to pot smoke for just 1 minute needed more than 90 minutes to recover.
The research team explained that they used a device that produced pot and tobacco smoke and pumped it into a sealed chamber. When the level of smoke was comparable to the ones found in pubs and restaurants, lab animals were placed in the chamber for one minute.
To learn whether second hand smoke affected FMD in any way, researchers temporarily blocked blood flow within the animals’ legs after exposure to smoke. Minutes after, they allowed blood to rush back into blood vessels and measured the FMD levels.
Springer and his team explained that studies on marijuana are extremely hard to conduct because the drug is illegal so research groups need a series of approvals from the FDA, DEA and other agencies before starting an experiment.
People falsely believe that second hand smoke from pot is harmless because there aren’t as many studies on its harmful effects as those on tobacco, researchers concluded.
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