The ‘12-3-30’ Treadmill Routine Is Crazy-Popular on TikTok—But Is It Actually a Good Workout? Health.com 1/28/2021 Replay Video UP NEXT The treadmill—or as many people call it, the dreadmill—doesn't typically get a lot of love. But thanks to a recent viral TikTok trend, this fitness tool is receiving tons of hype. The trend, known as the "12-3-30" workout, is soothingly straightforward: You set your treadmill to an incline of 12 and a speed of 3 miles per hour and then walk for 30 minutes. The concept originated from social media influencer Lauren Giraldo, who shared it on YouTube in 2019 and again on TikTok in November 2020, where a video explaining the workout racked up nearly 12 million views and more than 2.7 million likes (and counting).