MISSION, Kan. (AP) — Outdoor conditioning while a heat advisory was in effect during the humid summer left 15-year-old football player Ovet Gomez Regalado pale and asking for water.

After a 15-minute exercise, he collapsed as he walked to a building at his suburban Kansas City high school and died two days later of heatstroke, the medical examiner’s office wrote this month in a report that followed a weekslong investigation.

That makes Regalado the latest in a series of teen football players to succumb to heat-related illnesses during searing temperatures and high humidity.

The Johnson County, Kansas, medical examiner’s report said the temperature on the fateful Aug. 14 afternoon was 92 F (33.3 C). National Weather Service data shows temperatures rising over the the two-hour period that Regalado collapsed, from the mid-80s to around 90.

The high humidity made it feel much hotter, though.

Obesity also contributed to his death; Regalado weighed 384 pounds (174.2 kilograms) and had sickle cell trait. People with the trait are more likely to have problems when their body needs extra oxygen, as happens in extreme heat and after intense exercise.

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Jeremy Holaday, assistant executive director of the Kansas State High School Activities Association, said only weights and conditioning activities had been permitted since it was still preseason.

“To our knowledge that is what was taking place,” Holaday said.

He said the association recommends using a wet-bulb globe thermometer to monitor heat, and a chart on the association’s website recommends when outdoor activities should be alerted or halted altogether based on the readings. The metric is considered the best way to measure heat stress since it includes ambient air temperature, humidity, direct sunlight and wind.

The heat and humidity figures listed in the medical examiner report, when plotted on the association’s chart, suggest it was too hot for outdoor workouts. But the slightly lower temps the National Weather Service reported were on the cusp.

The situation was complicated by the fact that temperatures were rising.

Because Regalado’s death followed an offseason workout, the district oversaw the investigation, rather than the activities association. The district said in a statement that staff acted in accordance with association rules and school emergency action protocols.

After Regalado collapsed, ice bags were used to cool him down, the medical examiner’s report said. But his body temperature was 104.6 F (40.3 C) when emergency medical services arrived. They used several rounds of ice buckets and managed to lower his temperature to 102 F (38.9 C) before rushing him to a hospital. He went into multisystem organ failure and died two days later, according to the report.

“For all those who knew and loved Ovet, this report reopens the painful wounds that came as a result of his premature death,” the district said in a statement. “His absence is deeply felt in the Northwest community, and nowhere more profoundly than by his family, including his brother, who continues to attend Northwest.”

David Smith, the district spokesperson, declined to say Thursday whether Regalado had completed a student physical. Smith said the physicals were due when regular season practice started Aug. 19, five days after he collapsed. Smith said he wasn’t able to comment further out of respect to the family’s privacy.

The Shawnee police department also conducted its own investigation, which was closed with no further action taken, said Emily Rittman, the city’s public safety information officer.