"It's not the end," said the time-trial gold-medallist at Atlanta, "it's just a step along the way."
"I have to think about what I am going to do now. It's likely that I'll have to undergo medical tests for a few days at Pamplona," added the Spaniard.
"I want to recharge the batteries and nurse my cold as best as possible so that it doesn't get worse.
"The season has been a long one, and I need some rest."
Indurain pulled out of the Tour of Spain on Friday complaining of possible bronchitis.
He is yet to announce if he will participate in the October world championships and whether he will ride for the Banesto team next year or retire from the sport.
The Olympic road champion, who won the women's Grand Prix des Nations on Saturday, said she would arrive in Germany on Tuesday and would probably stage a first attempt at the record of 47.411 kms on Sunday.
McGregor set her mark in Manchester on June 17 last year.
Longo, who failed to beat McGregor's record last November, said she had hoped to go to Mexico or Colombia but found it too costly.