BEIJING — Intense attention to Beijing’s air pollution has obscured the more basic challenge athletes could face from heat and stifling humidity as the Olympic Games get under way here Saturday.

The official temperature in the Chinese capital soared to 96 degrees last weekend and the relative humidity reached 88% at one point. In certain outdoor venues, such the beach volleyball stadium in a park close to the city center, temperatures could surge well past 100 degrees.

“That’s a huge question for us in our sport,” one of the American women’s beach volleyball stars, Kerri Walsh, told The New York Sun. “You’ve got to just take care of yourself and have some foresight. Just understand that it’s 88% humidity and it’s 96 degrees and that’s certainly going to take effect on you even if you feel like you’re okay. So, we’re very aware of that.”

Ms. Walsh said that in recent months she and her teammate, Misty May-Treanor, tried to arrange practice that would simulate the likely conditions in Beijing, but the weather did not cooperate. “We had two tournaments on the East Coast and they were like the driest weekends, the least amount of humidity, they’d had in 10 years. We were like, ‘What’s going on? We wanted to prepare for Beijing,’ so, no, we haven’t got a lot of training in” the humidity, she said.

Ms. Walsh, a Saratoga, Calif., native, said the heat alone should not be a problem for her and that it’s possible the humidity might even have some benefits. “It makes my joints feel better. I’m 30, almost, now. Every little edge helps,” she said.

American Olympic officials said that even as the press seized on the pollution issue, coaches for outdoor sports have stayed focused on the weather. “In regards to the heat and humidity … we knew that was going to be elements that our athletes needed to be prepared for in Beijing,” the chief of sport performance for the U.S. Olympic Committee, Steven Roush, said in response to a question from the Sun. “There are other remedies that we’re using such as cooling vests that will allow them not to overheat on the day of their competition.”

Mr. Roush said he’s confident International Olympic Committee officials will postpone outdoor competitions if the weather is too oppressive. “I know that the IOC medical commission is monitoring that as well and will not put athletes in harm’s way in these Games. So, we will take their lead but do everything we can within our control to assist our athletes in not having that hamper their ability,” he said at a news briefing Wednesday.

A meteorologist with the Canadian Olympic Committee, Doug Charko, said the conditions in Beijing are likely to be more extreme than in Greece in 2004.

“Athens was hot, on par with the air temperatures in Beijing and sometimes greater. But Beijing is much more humid and the humidity is what makes it feel much hotter,” Mr. Charko said in an e-mail message to the Sun. “Atlanta, on the other hand, had conditions in 1996 more similar to Beijing.”

The basic problem caused by high humidity is that sweat does not do much to dissipate heat generated by athletic exertion. “The cooling effect of evaporation of sweat from the skin is not as efficient when the weather is humid, so you feel it a lot more,” Mr. Charko said.

The most elaborate preparations for extreme heat and humidity have been made for equestrian events in Hong Kong, where relative humidity is usually even higher than in Beijing. Horses are being moved in air-conditioned trailers and 30 tons of ice have been shipped in to fill ice jackets that will cool the horses after they compete.

Athletes aren’t the only ones who could be felled by the heat and humidity. Spectators, who are usually less fit, could fall out as well. Although a musical performance in Beijing’s Tiananmen Square was staged at 7 a.m. this week in order to dodge the midday heat, several participants were seen being led away by a medical team before the show ended at 9 a.m.

“I’m a little more concerned about my family walking around, you know?” Ms. Walsh said in the interview Wednesday, during the opening of an Olympic team training center sponsored by the 24-Hour Fitness chain. “I think they feel, ‘We’re not working out,’ but the sun sucks your energy and your sweat and everything. People just need to be smart.”