Madonna's friends are thought to be worried she "burnt herself out" with an "extremely risky" workout schedule while trying to compete with younger stars like Taylor Swift.
A source has said the singer's friends feared there would be "another Michael Jackson situation" after he died in the run-up to his This Is It tour in 2009.
Madonna, is thought to have been constantly pushing herself in the run up to her Celebration Tour, which her pals think contributed to her hospitalisation.
The 64-year-old was intubated while in an intensive care unit after suffering a serious bacterial infection. She is now at home recovering, but has been forced to postpone her world tour.
A source has said Madonna was "working overtime" while focusing on her upcoming shows, with people having to remind her that she is "not 45 any more, let alone 25".
They added that she was struggling to "pace herself".
Speaking to The Sun, the source said Madonna's friends had "encouraged her to take it easy" and take a break from her "gruelling schedule".
"Many of us feel the constant remarks about her age have put pressure on her to compete, so we are relieved that she has been forced to take time out and put her health first," they said.
"People were really worried about her.
"Nobody would say it out loud but there were concerns about another Michael Jackson situation if she doesn't slow down a bit."
The source said the Queen of Pop is now happy and at home and is hoping to perform as many tour dates as possible once she has regained her strength.
She is said to be working with a group of doctors to try and boost her immune system so she can get back to work.
Madonna's tour was due to start on July 15, but it has now been postponed. A new start date will be announced soon.
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