Carrie Underwood secretly "competes" against other gym goers

She said: "I love just putting headphones in and going for a run. I feel so good when I get home, especially when it's hot. I'm one of those weirdos that likes to run when it's super hot outside! Or classes. I find myself competing with other people in the room. I'm like, 'Oh she's good, I want to be like her!' I try to 'beat' someone in the class. They have no idea we're competing!"

Carrie has just launched her own fashion line and admitted using her own workout gear is extra motivation to hit the gym.

She explained: "I used to go to the gym in ratty old sweats, but if you already feel good going into your workout, it just kind of gives you that little extra lift."

And being a mother to Isaiah means Carrie doesn't always have time to fit in a proper work out and instead uses activities she does with her family to exercise.

She told People magazine: "It just happens if and when it happens.

I’ve gotten a lot better at doing what I can when I can, but also cutting myself a little slack. You have to!

"Now it’s like, ‘Okay, I have 20 minutes. What can I do in 20 minutes?' I can go run for a little while, I can go do some tabata rounds, I can do something. Sometimes I’m like, my workout today is going be running around after my kid. If we’re going to go to the park, why not run there and push him in the stroller? Then I get a good cardio session to and from, and then he gets to play, so everybody wins."