Formula One team bosses have asked organisers to limit the number of back-to-back races during the season.
McLaren boss Ron Dennis is among those calling for change
This season is the busiest in the history of the sport, with 19 races from March to October and more races are planned for future years.
"Last weekend in Montreal I walked up and down and you could see everybody was extremely tired," admitted McLaren boss Ron Dennis.
"So it's just too intense at the moment, it really is."
Formula One is in the middle of a run of four back-to-back race weekends.
And some teams have hired extra staff to cope, allowing team members to miss occasional races in order to catch up with life at home.
Dennis saw his team work into the night in Canada on Sunday before the trip south to Indianapolis.
"You've got the psychology of not getting the result that you wanted blended with three hot days and they're all back at work effectively Tuesday lunchtime.
"The impact also is dramatic on the families because you would think, of course, that they go back and have a rest, but there is no rest.
"They get back, and within two or three days they're working preparing the cars for the French Grand Prix. So it's just too intense at the moment, it really is."
But BAR chief Nick Fry wonders whether the current schedule is too much for Formula One fans.
"I think when races are that close, just how willing people are to give up their Sunday afternoons or will they be allowed to give up their Sunday afternoons to watch motorsports four out of five times?
"I think we should be the entertainers but I think the public needs to tell us whether they want that many races.
"For me, I don't know the answer but I think spreading them out a little bit is probably a better move. If that means reducing it a little bit, then so be it."