"When I got out of rehab, I needed to lose weight, but I also needed to figure out a way to function sober," the rapper tells Men's Journal in its September issue. "Unless I was blitzed out of my mind, I had trouble sleeping. So I started running. It gave me a natural endorphin high, but it also helped me sleep, so it was perfect."
Continues Eminem: "It's easy to understand how people replace addiction with exercise. One addiction for another but one that's good for them."
However, the musician – who says the coating on the Vicodin and the Valium he'd been taking for years left a hole in his stomach, causing him to eating constantly and badly in order to avoid a stomachache – took his running to the extreme.
"I became a f---ing hamster. Seventeen miles a day on a treadmill," admits the rapper, who says he ran to the point of injury. "I would get up in the morning, and before I went to the studio, I would run eight and a half miles in about an hour. Then I'd come home and run another eight and a half. I started getting OCD about the calories, making sure I burned 2,000 every day. In the end I got down to about 149 lbs."
He continues: "I ran to the point where I started to get injured. All the constant pounding from the running began to tear up my hip flexors."
So the rapper turned to TV – Shaun T, to be exact.
"I know a lot of these DVD guys are wacky, but I'm alone in my gym; I need someone on the TV yelling to motivate me," says Eminem. "Besides, some of this s--- is entertaining."
"When I first started the Insanity workout, I alternated my routine, running one day and doing the Insanity the other. Then I stopped running altogether because it was too much to do them both. The Insanity won. After a while … I mixed it up. I did the P90X for a little while (and I still do that ab workout because it's the most challenging) … Now every morning before I go to the studio, I do the Body Beast workout with free weights, bench, and pullup bar at home. It's just me, so it helps that the Body Beast dude is over-the-top."
The rapper says that the first time he did the leg routine, "I couldn't walk for two days."
He admits it's a far cry from the old days when he'd hit the gym with Dr. Dre and had to "lift the kiddie weights."
"Once you're at a place where you've made progress and you've got some time invested in it," the rapper says, "you don't wanna quit and give up what you started."