Lewis Hamilton believes a Formula One race should be as exhausting as running a marathon, with the Mercedes man claiming he could drive three in succession before feeling fatigued.
The defending champion has made a stellar start to 2019, winning four of the opening six races of the season to claim a 17-point lead atop the standings ahead of team-mate Valtteri Bottas, who has prevailed in the other two meetings.
Ahead of this weekend's Canadian Grand Prix, where he has triumphed six-times previously, Hamilton expressed his belief that modern-era racing was too easy on the body.
"You should be just so physically exhausted after the race, it should be exhausting like a marathon," he told a news conference.
"I could probably do two or three races in a row and Formula One should not be like that.
"It's a man's sport and a lot of youngsters come in and it's quite easy for them to get straight into it.
"But I do think it should be the most physically challenging and probably why a lot of us drivers are able to go for a long period of time is because we can handle it."
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And Hamilton believes rule alterations in recent seasons have been to the detriment of the sport.
"If you look over the last 12 years and beyond that, they always shift and change the regulations for the car, try to improve costs, try to improve overtaking and I think in general the decisions have not been great in all of those years," he added.
"Liberty [Media] has taken over now and you still have the same issue: people are not so excited, we still have that separation between all the top wealthier teams and the lower teams."