The economics of the endurance-event business make a pandemic particularly problematic. Registration fees produce as much as 80 percent of revenues, and 80 to 90 percent of that money is spent on expenses weeks and months in advance of race day, including purchases of medals, T-shirts and permits. A canceled race owned by a mom-and-pop business that has to issue refunds or deferrals can sink the event or the business, said Rich Harshbarger, the chief executive at Running U.S.A., an industry trade group.

Ironman, the world’s best-known triathlon series, is transferring competitors from canceled or postponed events to races later in the year or in 2021, rather than giving refunds. Not everyone is happy about that.

Barbara Marinoni, who lives in suburban Toronto, spent more than $1,000 to register for a half-Ironman in Muskoka, Ontario, in July, which may be canceled, given Canada’s approach to dealing with Covid-19 so far, and for a full Ironman in August in Mont-Tremblant in Quebec, which probably will be, since Quebec’s provincial government has canceled all sports and cultural events until Aug. 31.

“I would rather have the money refunded, or I think at least there should be some portion refunded,” said Marinoni, a supply chain executive who isn’t ready to commit to races that won’t happen for another 16 months.

Andrew Messick, chief executive of Ironman, said the company chose a policy of race substitutions instead of refunds because most athletes he heard from were not interested in getting money back. They just want to race and to know when they can. “The training and the races provide a structure to their lives that they find really valuable,” Messick said.

Most race operators are far smaller than Ironman and may have less flexibility.

“If the summer gets wiped out, we will have to get very creative,” said Stephen Del Monte, owner of DelMoSports, which owns and operates a half-dozen races in Philadelphia and South Jersey.