Just one minute of inhaling second-hand cannabis smoke can affect arteries for up to 90 minutes, warns new research.
The study shows cannabis smoke reduces the amount of blood carried by arteries for three times as long as normal cigarette smoke – the effect of which lasts just 30 minutes.
Blood vessel function was examined in rats before and after exposure to second-hand marijuana smoke at levels similar to real-world second-hand tobacco smoke.
Senior study author Professor Matthew Springer, of University of California, San Francisco, said: “While the effect is temporary for both cigarette and marijuana smoke, these temporary problems can turn into long-term problems if exposures occur often enough and may increase the chances of developing hardened and clogged arteries.
“Arteries of rats and humans are similar in how they respond to secondhand tobacco smoke, so the response of rat arteries to secondhand marijuana smoke is likely to reflect how human arteries might respond.”
Researchers also found it was the burning of cannabis itself that was responsible for the impaired blood vessels, not chemicals like nicotine and tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana.
Prof Springer added: “There is widespread belief that, unlike tobacco smoke, marijuana smoke is benign.
“We in public health have been telling the public to avoid secondhand tobacco smoke for years, but we don’t tell them to avoid secondhand marijuana smoke, because until now we haven’t had evidence that it can be harmful.”
Essentially, scientists believe inhalation of smoke should be avoided – regardless of whether it comes from tobacco, cannabis, or other sources.
The research was published by the journal of the American Heart Association