Published Wednesday, 23 October 2013
The Price Tag hitmaker suffers from a congenital heart problem which brought on a stroke in her teens.
Her hectic touring schedule can often leave her run down, and over the summer she cancelled shows in Ireland and France as she fought off illness.
However, the singer reveals that rather than offering her support, some fans take to social networking sites to threaten her with vile abuse.
She tells Time Out magazine: "I still have a heart deficiency and have days when I struggle. The fans don't get that sometimes. The abuse that you get if you cancel a show... it's scary.
"I've had death threats for cancelling shows! With social media young people use words of hatred so flippantly now. It's either, 'I love you!' or, 'I hate you and I want you to die!' There's no middle ground. Everything's an extreme because people want to be noticed.
"I used to comment back but I've learned not to do that. I've had fans go, 'I didn't mean it. I just wanted to get your attention.'"
The star has previously warned youngsters of the dangers of using social media, insisting it is a breeding ground for bullying.
She said: "Children used to get bullied at school. Now they go home and that's where the problem starts, because they sit on their phones all night, thinking about who's 'liked' a photo of them, who hates them, who loves them.
"They don't know what's real and what's not, editing their lives constantly to fit other people's views."