The socialite, who is engaged to basketball star Kris Humphries, explained that she always feels "good" after exercise.
"I'm at my sexiest right after I leave the gym. I always feel so good, I also like being glammed up though," she told More.
"Every girl has their insecurities but I've become more comfortable with my body as I've grown older.
"Although I do work out hard - there's always room for improvement. If I'm at home I work out every day, but with travelling so much it's hard."
The Keeping Up with the Kardashians star also insisted that confidence is the sexiest quality about a person.
Kardashian added: "Confidence is sexy. If someone is really insecure, they can come across as really unsure of themselves.
"And if you have body issues, it can roll over into your work and the rest of your life. I think confidence is just the sexiest thing."
Kardashian recently revealed that she intended to marry Humphries after dating him for just two months.
