Naomi Campbell thinks she should do more exercise.

The 40-year-old supermodel admits she doesn't work out as much as she would like to but believes having a healthy mind keeps her fit.

She said: "Actually, I don't work out as much as I should, but I do believe that it's a healthy mind as well as a healthy body that keeps me fit, sound and calm."

However, one exercise Naomi is fan of is swimming and has been doing a lot of it since moving to Russia to be with her Russian real estate entrepreneur boyfriend Vladislav Doronin.

She told Britain's GQ magazine: "Since I've been living in Russia, I noticed most people here swim the butterfly. I can't swim the butterfly, but I was just in the Dead Sea in Jordan and it was the first time I floated in my whole life."

While she doesn't exercise as much as she would like, Naomi recently revealed she undergoes an extreme detox three times a year in a bid to maintain her stunning figure.

The supermodel admitted she has just Maple syrup, cayenne pepper and lemon juice in a cocktail form for days on end and credited it with her being able to stay in shape.

She said: "I try to do this three times a year. The most I've ever done it for is 18 days. So I started on Sunday. This is the sixth day.

"It's good just to clean out your body once in a while."