Tokyo held a marathon on Sunday as a test case for whether organizers, athletes and spectators can cope with sweltering temperatures expected during next year's Summer Olympics and Paralympic Games.

Sunday's race featured tents equipped with mist machines for spectators. Officials handed out ice cubes and ice scarves to families waiting in the sun. At some of the rest stops officials said they also planned to give out plastic hand-held fans.

Runners were optimistic that the athletes would be able to deal with the heat during next year's Olympics, but some spectators expressed concerns about cheering runners in sweltering conditions.

"Yesterday it was cool, but near the end [of the race] the sun came out," said Rei Ohara, who collapsed after finishing third in the women's race.

"Then I felt the heat but the organizers gave us ice and water so I think it was a race that was easy to run for everyone."

Organizers have been sweating over how to protect athletes from heat stroke and keep spectators cool during Tokyo's notoriously hot and muggy summers.

Temperatures in Tokyo during July and August, when the city will host the Olympic and Paralympic Games, commonly exceed 30 C, with high humidity adding to people's discomfort.

On Sunday, temperatures were as high as 30 C, but hovered around 22 C in shaded tents next to the road.

"We will analyze all of the know-how and measurements we were able to gain today to improve our measures to combat heat," Tokyo Governor Yuriko Koike told reporters.

Organizers plan to start the marathons at 6 am next year to avoid midday heat, with major roads on much of the 26-mile course painted with a resin that the organizer say will reflect infrared rays to cut temperatures as much as 8 C.

Sunday's test race began at around 8:50 a.m. for men and 9:10 a.m. for women.

Last month, heat concerns prompted the International Triathlon Union to shorten the distance of the run segment in a qualifying event in Tokyo for the July 24-August 9 Olympics.

Hideo Nakatani and his wife Kuniko had traveled from their neighborhood in Machida in Tokyo to cheer on the ­runners in the marathon Sunday morning.

Both are avid runners and worried that Tokyo's summer temperatures might affect the runners next year.

"I know the actual event will be held earlier in the day next year but it's still going to be humid and really hot," said 66-year-old Hideo, who wore a hat, sunglasses and iced scarf around his neck.

"We will probably have to be really prepared for the sun when we come as spectators next year."

Heat was not a problem last time ­Tokyo hosted the Games in 1964 because it opened in October. Since 1976, however, most summer games in the northern hemisphere have been held in the middle of summer to fit with global broadcasting schedules.

At a beach volleyball test event in July the wet bulb globe temperature, which factors in temperature, humidity, wind speed and solar radiation, as rising as high as 31.7, exceeded 31, a threshold at which authorities urge citizens against exercise.

The top two finishers in Sunday's race won spots at next year's Summer Games.