Michael Schumacher has reportedly lost so much weight he is now only 8 and a half stone.
The former F1 racing driver has lost 25% of his body weight while remaining in an artificially induced coma for 83 days.
He was placed in a coma on December 29, 2103 after suffering serious brain injuries following an accident on the slopes of the French resort of Meribel, where he was on holiday with his family.
He was transferred by helicopter to the University Hospital of Grenoble. He has undergone two major operations since the accident.
Prof Dr Curt Diehm, of the Karlsbad teaching hospital in Germany explained that while the racing champion's muscles and joints are massaged daily, it was not enough to prevent muscle shrinkage.
"While a weight loss in coma patients is normal, 20 kilos is a lot for people with normal body weights. One must assume that his muscles have degraded greatly due to the immobility," he added.
Schumacher family and manager Sabine Kehm have said they remain optimistic that the seven times world champion will make a full recovery, however the medical team have seen few signs that he recognises his external environment, stating that only a miracle can help him.
If he does emerge from the coma, it has been suggested he will need many years of intensive therapy to regain full limb movement and speech.
In a worst-case scenario the Formula One champion will be left in a 'waking coma,' a permanent vegative state where he is conscious but unable to move or speak.
Schumacher's wife Corinna, his daughter Gina-Marie, 17, and son Mick, 14, have maintained a constant vigil by his bedside for eight hours of the day, talking with him in the hope of some sign of recovery.
Some of sports greatest stars have been sending messages of support to the family.
With the start of the 2014 racing season, Bahrain renamed the first corner after the F1 legend, while winner of the Melbourne Grand Prix Nico Rosberg dedicated his victory to him.
Mercedes' executive director Toto Wolff said: "This victory has a very special meaning for us. I would like to dedicate it to Michael, who has been in all our thoughts this weekend. He will keep fighting, as only he knows how, and we are sending all our strength to him."