Doctors have ended their strike and returned to work amid new hope that a deal over changes to their contracts can be reached before the next planned 48-hour walkout.
Thousands of junior doctors walked out for 24 hours, while around 4,000 operations had to be cancelled.
Two further strikes are planned but talks are expected to resume in an effort to break the stalemate.
Talks to prevent further strikes by junior doctors will resume on Thursday, Acas said.
In a statement, Acas, which aims to resolve employment disputes, said:
Retired Dr Henry Goodall, who was a junior doctor in 1970, says the current generation are "used to working less hard with fewer hours".
As junior doctors in hospitals across England go on strike for 24 hours today, a junior doctor writes for ITV News on why she is striking.
A government aide was filmed trying to prevent a reporter asking why Jeremy Hunt was not speaking ahead of today's national doctors' strike