Olympic test events are supposed to be just that — a litmus test for Olympic hopefuls, the host city, and the international sports federations responsible for the competitions.

This summer’s events in Tokyo have mostly been a test of how to manage the heat. On Thursday, the women’s triathlon was shortened because of dangerous temperatures.

Tokyo officials had already added extra water stations and positioned medical personnel every 500 meters on the run course, added more air-conditioned areas for athletes before and after the race, and set up massive ice baths for competitors past the finish line.

But the heat forecast was extreme — too extreme for a full-length competition.

At 3:30 in the morning, representatives and delegates met to measure the water quality, water temperature and weather forecast for the day ahead. The meeting was not out of the ordinary. Water temperatures and quality must be tested to ensure the safety of the athletes, according to the rules of the International Triathlon Union, the sport’s world governing body.