"Do you want a player to die on court?"
That was the question Holger Rune asked an official as he was treated by a doctor and physio in gruelling conditions at the Shanghai Masters.
With temperatures reaching as high as 34C and humidity at 80% in the daytime at the end of a long season, players are feeling the impact physically.
Conditions are similar 500 miles west at the Wuhan Open, where Emma Raducanu retired from her first-round match on Tuesday with dizziness. On Monday, matches on the outside courts were halted and the roof on the main court closed.