[82lsju]

P.S.  Wonder if a race car driver ever sat one out because the head wasn't right?  Wouldn't blame him/her - and neither would their competitors I suspect.  Talk about life-threatening.

Stirling Moss retired when he was 32, while regarded as one of the best Formula One drivers in the world. He was involved in a horrific accident and after he returned he tested a few times and stated that he didn't feel that he was at his previous level and wasn't comfortable resuming his career. Not exactly what you asked, but it was clear that even though he had recovered he felt that even a slight drop-off in performance was too dangerous.

Niki Lauda pulled out after two laps in the 1976 Japanese Grand Prix because he thought it unsafe to continue in the rain, he was three points ahead in the Championship entering the race and ended up losing the championship by one point to James Hunt (the Japanese Grand Prix was the last race of the season).  Lauda had been severely burned earlier in the season in a crash at the German Grand Prix, he was so badly injured in that race that he was given last rites while in the hospital.  He had tried to organize the drivers to boycott the German Grand Prix due to safety concerns at the track but failed to get much support.

[82lsju]

P.S.  Wonder if a race car driver ever sat one out because the head wasn't right?  Wouldn't blame him/her - and neither would their competitors I suspect.  Talk about life-threatening.

Stirling Moss retired when he was 32, while regarded as one of the best Formula One drivers in the world. He was involved in a horrific accident and after he returned he tested a few times and stated that he didn't feel that he was at his previous level and wasn't comfortable resuming his career. Not exactly what you asked, but it was clear that even though he had recovered he felt that even a slight drop-off in performance was too dangerous.

Niki Lauda pulled out after two laps in the 1976 Japanese Grand Prix because he thought it unsafe to continue in the rain, he was three points ahead in the Championship entering the race and ended up losing the championship by one point to James Hunt (the Japanese Grand Prix was the last race of the season).  Lauda had been severely burned earlier in the season in a crash at the German Grand Prix, he was so badly injured in that race that he was given last rites while in the hospital.  He had tried to organize the drivers to boycott the German Grand Prix due to safety concerns at the track but failed to get much support.