Beneath the "it girl" persona she has embodied for decades, says a previously "burnt out" body lays. 

Aniston, 54, says the way she previously attacked her workouts was not only "daunting," but also debilitating.

"When you're in a mindset of, 'I need to do 45 minutes of cardio or I won't get a good workout,' it's daunting," she told InStyle. 

"I believed it for so long. I just burnt out and broke my body." 

"You're not thinking, or really getting a good workout, when you're doing something over and over again," she explains of her previous regimen, which included "the monotony of banging yourself out on a treadmill for 45 minutes.

" 

The activities took such a toll on Aniston that she says, "My physical therapist gave me a Barbie doll that's covered in Kinesio tape" to illustrate "every injury I've had in the last 15 years."

Aniston said she has since pivoted to .

The actress said the best part of her new routine is that "After a workout, I don't feel insane fatigue or broken or in pain."

She also noted that she likes to work out with friends, rather than alone.

"Doing your own workout by yourself, meh. If you get some good music going you can have fun, but I like to be guided.

It's too easy for me to do things less correctly than I should."

Aniston recently told People about her old mindset when it came to working out. 

"Our minds used to think, we have to hurt; no pain, no gain. It has to be an hour of a workout. You have to work out three times a day." 

"Especially as we get into our lovely older periods, we have to keep it exciting. And we have to be kinder to our bodies," she explained. 

Even with exercise, the former clarified that she does not restrict herself.

"It's just calories in, calories out, nutrition, what are you feeding your body? Don't

. You've got to get the right amount of sleep. You've got to drink tons and tons and tons of water. You also have to give yourself the 20% of fun and gluttony and have a good time and indulge," she told People. 

"For me, I couldn't do that saintly, never go off the rails or deviate from the plan of perfect wellness because I like to enjoy myself."

Caroline Thayer is an entertainment writer for Fox News Digital. Follow Caroline Thayer on Twitter at @carolinejthayer. Story tips can be sent to [email protected].