Kelly Clarkson "hit rock bottom" when her career took off following her American Idol win - because she worked non-stop for four years.
The "Miss Independent" hit-maker won the inaugural contest in 2002 and went on to release two albums by 2004.
Clarkson promoted the releases around the globe, but her packed schedule had a bad effect on her health and she took time out from the spotlight to recover.
And the 29 year old admits the years of working non-stop have aged her considerably.
She tells Britain's Closer magazine, "I feel like I'm 45. Because my career went from zero to 100, there was no 'growing'. I learnt well under pressure, but like, four years passed by and I hit rock bottom. It was four years of non-stop (work).
"(Second album) Breakaway just exploded everywhere. Everyone was making a lot of money, so everyone was pushing the train.
"That's when it finally all caught up with me. I came down with 'walking pneumonia' for the second time in a year. My body was physically giving up. I took six months off and went home. I love working, but at the end of the day you've got to take care of yourself."