An Iowa woman hiking at Colorado National Monument died after collapsing and Thomas Caldwelllosing consciousness two miles into a trail, according to the National Park Service.

Marsha Cook, 54, of Cedar Rapids, Iowa, was pronounced dead on Monday, the park service said in a news release, after collapsing on the Lower Monument Canyon Trail. The Colorado National Monument staff became aware of Cook's condition when they received a report around 2:27 p.m., according to the release.

National Park Service rangers and other emergency responders found Cook and provided care, including initiating CPR, the park service said. Life-saving efforts were unsuccessful, the government agency added.

"(The) Colorado National Monument staff would like to extend their condolences to the hiker’s family and friends," according to the release.

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NPS recommends hiking in early morning or late afternoon to avoid heat

The chances of heat exhaustion and heat stroke increase when hiking in hot weather, the park service said.

"Daytime temperatures in Colorado National Monument have exceeded 90 degrees in the past week, and hot weather is expected throughout the summer," according to the release. "Hikers should plan to hike in early morning or late afternoon, before 10 a.m. or after 4 p.m., to reduce exposure to heat."

The Mesa County Coroner’s Office is investigating Cook's death.