For example, Rimes claims to take over 40 pills a day as part of staying fit.
"I take like 20 pills in the morning and 20 at night. Fish oil, prenatal vitamins, probiotics, biotin," Rimes explained. "I have an herbalist I work with who has put me on a bunch of different things. I’m very strict about making sure I take them."
The singer also admitted that she's struggled with psoriasis since she was a little girl.
"I had to wear a lot of long pants or jeans and two or three pairs of pantyhose in the summertime," Rimes recounted. "It was a nightmare."
To treat the condition, Rimes revealed that she takes additional medicine.
"I take a shot every two weeks, and I hate needles, but that’s what I had to do to get my skin clear," she said. "I went through every type of treatment known to man. Now, I'm on Humira -- it was a shot in the dark, and thank god it worked. I do break out every so often, but I have topical stuff that I put on for that."
"It’s been this liberating thing for me to be able to wear shorts and a bikini," Rimes explained. "People make so much fun of me and my bikinis, but I would walk around naked if I could because I was one big scab at one point!"
She also revealed how she keeps her bikini bod so evenly tan -- she owns her own tanning machine!
"My assistant, Kiki, and I love to spray tan so much, so we finally bought a machine and started to spray each other," she shared. "The machine is like $500, so we save so much money. We do it once or twice a week. It’s like a car wash."
But tanning and clear skin aren't the only things that make her feel comfortable about walking around in a two-piece. She also works hard to stay fit and tone.
"I switch it up between circuit training, Pilates, boxing, and yoga every once in a while," Rimes said of her varied workout routine. "I also jump rope a lot when I'm on the road. That's one thing that I carry with me because you can do it wherever."