Mercedes boss Toto Wolff says that he is concerned about the human cost of running more triple-header events in 2021.
The sport has traditionally avoided running three Grand Prix races on consecutive weekends, but was forced into an unprecedented four such runs when the start of the season was delayed to July by the onset of coronavirus.
Recognising the extraordinary circumstances, teams went along with it this season. But many have been dismayed to see two more triple-headers appear on the provisional 23-race schedule for next year.
Spa, Zandvoort and Monza will run back-to-back immediately after Formula 1's traditional summer break in August. And after just one week off, F1 will then be racing in Sochi, Singapore and Suzuka in consecutive weeks.
McLaren boss Andreas Seidl insisted in July that triple headers "cannot be the new standard going forward in future seasons". And Red Bull principal Christian Horner recently said that the provisional 2021 schedule "is on the limit of human tolerance."
Wolff said he understood the need to add more races to the schedule from a business point of view, but worried about the toll it would take on the team personnel and engineers involved in race operations.
"The teams are the beneficiaries of growing revenue and income,"Wolff acknowledged. "In that respect we all need to support for the business to grow.
"On the other side a couple of triple-headers will take a toll on the people," he told the media last week.
"I think there is an Asian triple-header that will mean we are more than three weeks away from home and that is certainly not something that is great.
"You mustn't forget that the hardest working people are the ones that set up the garages and take them down, and the mechanics that will have overnighters if something goes wrong.
"You need to question how long that is sustainable, and whether you implement a different system by having a second crew that can take over these toughest roles.
"This is something we are looking at at the moment," he added.
Haas F1 Team principal Gunther Steiner had similar concerns about the triple-headers and about the expansion of the calendar as a whole, with F1 CEO Chase Carey recently talking of aiming for a 24-race season in future.
"It will take a toll on the people," said Steiner. "On the people side we need to come up with plans that we don’t overwork them.
"We overwork them anyway, but we need to be clear that we cannot demand that all the time," he added. "We need to try it and try to find some solution where our people do not get worn out."
However like Wolff, Steiner admitted that the calendar expansion and resulting need for triple-headers was probably necessary from the business side.
"I think especially in the times we are in now we need to do it," he acknowledged. "It’s part of where Formula 1 is going.
"But then [commercial rights holders] FOM needs to look into it - if it's something we want to do for the long term, if this many races are sustainable, and if there is no saturation coming in.
"We will just find out in a few years if more races is the right way," he pointed out. "If it gives us more revenue we need to come up with ideas where we make it sustainable for ourselves, where we don’t need to wait until we are told to do that.