Venus Williams has revealed that she is suffering from an incurable immune system disease that had even threatened to end her career.
The tennis star said she was diagnosed with incurable Sjogren's syndrome a month before she withdrew from U.S. Open in August.
But she did not tell anyone about it even though she could feel the effects in her first match, which she won.
"I couldn't raise my arm over my head, the racket felt like concrete. I had no feelings in my hands. They were swollen and itchy. I realised it would be a miserable show," the Daily Mail quoted her as telling People magazine about her illness.
Sjogren's syndrome was first described in 1933 by Swedish eye specialist Henrik Sjogren. The condition causes antibodies to attack the body's moisture-producing glands, leading to dryness on the body due to lack of secretion.
The illness most commonly affects the eyes, mouth, salivary glands, lungs, kidneys, skin and nervous system but all organs of the body can be affected.
In rare cases, complications from Sjogren's syndrome can cause salivary gland infections, kidney problems, ulcers or pancreatitis.
The tennis ace said she worried the illness might mean the end of her career so decided to take a break.
She returned to her Palm Beach mansion where she lives with her sister to rest and try to get to grips with the syndrome.
At her Serena's recommendation she is seeking holistic alternatives like yoga and massage.
The former steak lover has also changed her diet to raw vegan dishes, which should help ease the inflammation on her joints.
"I've been going hard the past few weeks and it scares me, I need to avoid stress or I'll get sicker and go backwards," the two times U.S. Open winner said.