Aston Martin driver Lance Stroll said he was "passing out" and dizzy behind the wheel.
Esteban Ocon, racing for Alpine, vomited in his helmet during the race, he told reporters.
Medical officials evaluated Williams driver Alexander Albon for acute heat exposure, while his teammate Logan Sargeant retired from the competition after feeling sick and suffering from "intense dehydration."
Scorching temperatures at the Formula 1 Qatar Grand Prix on Sunday turned up the heat on elite drivers who already face physically demanding conditions on the track, from racing at extreme speeds to regularly experiencing elevated G-forces.
But it was so hot in Qatar that the Fédération Internationale de l'Automobile (FIA), the governing body of Formula 1, said it's considering taking steps to better prepare drivers for rising temperatures.
"While being elite athletes, they should not be expected to compete under conditions that could jeopardise their health or safety," the FIA said in a statement.
Qatar is already among the world's hottest countries, and with climate change, high temperatures will get even more extreme.
Mercedes driver George Russell said the temperature in the cockpit of his car exceeded 50 degrees Celsius — or 122 degrees Fahrenheit — ESPN reported.
The FIA is now conducting an analysis into the race and considering a raft of potential measures to deal with extreme heat in the future, such as providing additional guidance to competitors, researching how to improve cockpit airflow and changing the race calendar "to align with acceptable climatic conditions."
Temperatures are expected to be lower during next year's Formula 1 Qatar Grand Prix scheduled for Nov. 29 through Dec. 1., but the organization also said it "prefers to take material action now to avoid a repeat of this scenario."
The FIA plans to discuss the potential recommendations at its upcoming medical commission meeting in Paris.
Three-time world champion Max Verstappen, racing with team Red Bull, won the Qatar Grand Prix on Sunday, followed by McLaren's Oscar Piastri and Lando Norris.
