As competitors battled for the podium on the third day of Olympic athletics on Sunday, it was Tokyo’s stunning heat that perhaps dished out the most pain.

Punishing conditions greeted athletes and officials as a trackside thermometer touched 40 degrees Celsius (104 Fahrenheit) and the humidity hovered around 60%, with sun beating down on the fan-free National Stadium.

Sweat-soaked reporters donned wet towels as the women’s 3,000-meter steeplechase qualifiers played out, the event’s trademark water hazard appearing more enticing than ever.

The risks of heatstroke at one of the hottest Games on record are borne by the athletes, but also by the thousands of staff, especially at outdoor venues.

Some 30 people involved in the organization of the Olympics have suffered heat-related illness so far but all had mild symptoms, Games director general Toshiro Muto said.