But Oliveira insists his the problem has nothing to do with his on-field performances.
Beckham was pictured using an inhaler during the MLS Cup final against Real Salt Lake on Sunday.
“David has suffered with this since he was a young boy but it has obviously had no effect on his performance,” Oliveira stressed to The Daily Mail.
“He has never sought to make it public but if it does inspire any sufferer to think they can achieve great things like many other sportsmen have done then so much the better.”
