The heart-rate monitor on the Apple Watch is useful for everything from tracking workouts to detecting a wide range of medical conditions, but one group of people have seemingly found another use for it: attempting to make recreational drug usage safer …

CNBC reports that users of cocaine, ecstasy, ketamine, speed and other drugs are using smartwatches to monitor their heart-rate.

By ceasing use of the drug when their heart-rate is too elevated, they believe they can reduce the risk of a heart-attack.

“If someone says, ‘Let’s do a line,’ I’ll look at my watch,” Owen said. “If I see I’m at 150 or 160, I’ll say, ‘I’m good.’ That’s totally fine. Nobody gives you a hard time.”

Doctors and medical academics, unsurprisingly, say that this provides a false sense of security.

Indeed, says Weiss, it could even be counter-productive.