Thankfully, marijuana smoke doesn’t appear to significantly increase your risk of lung cancer. But a vaporiser is a smart move. In one study, habitual marijuana smokers who were prone to coughing saw their respiratory symptoms improve 73 percent after they switched to a vaporiser.

They could also puff more air out of their lungs than they’d been able to back when they were still lighting up. Now here’s some bad news: The real marijuana risk has less to do with your lungs than your brain. Of 5,115 adults in a 25-year JAMA Internal Medicine study, those who smoked regularly into middle age had worse verbal fluency than those who cut the habit while they were younger.

Also, the more years people smoked marijuana, the less adept they were at recalling words from a list of 15.

Weed isn’t just slowing down your brain – it’s stalling your sperm too. Find out why