Arizona State University hockey player Matthew Mayich remains hospitalized in a coma nearly two weeks after collapsing during an outdoor team workout in Tempe on Aug. 20. The family's attorney described his condition to reporters in blunt terms, telling the Arizona Republic that the 21-year-old defenseman has no chance of recovery. Mayich, a St. Louis Blues draft pick who transferred from Clarkson University, has been moved to Barrow Neurological Institute in Phoenix.
Emergency responders were called to a report of heat-related illness. The university says it is reviewing the session. No medical diagnosis has been released, and no hospital or agency has confirmed a cause.
For families across Phoenix, Houston, Dallas, Las Vegas and other hot weather metros entering fall sports season, the case raises a question that has nothing to do with elite athletics. Heat illness does not spare fit young people. It often escalates during the first days of outdoor training, before the body has adjusted, and the difference between a scare and a catastrophe is measured in minutes.
Inside the Timeline Investigators Are Examining
Mayich collapsed on the first day of the fall semester, which his family's attorneys say was also the first day players were permitted to practice. He had flown in from Ottawa and, according to those attorneys, had been on campus less than a week.
Family attorney Leonard Aragon told ABC15 the session ran with minimal water breaks, lasting more than an hour, and said not all players were given water. Attorney Rob Carey, who is also representing the family, told the Arizona Republic that players described being pushed without standard breaks. These are allegations from the family's legal team, not findings by the university or any regulator.
The workout was led by a former Green Beret, Tim Ziesel, who volunteered at the head coach's request and is not a university employee. Ziesel disputed the characterization of the session, saying it resembled a high school football conditioning routine rather than a military exercise, and said he left before Mayich collapsed. His attorney said coaching and medical staff were present throughout and called for a thorough investigation. The university has acknowledged that a third party who had previously worked with the team was present alongside coaches and training staff. Reporting by the Arizona Republic put the temperature at the time between 87 and 89 degrees, a figure not independently confirmed.
Phoenix Heat Data Shows a Worsening Season
The collapse landed in the middle of an unusually deadly summer in metropolitan Phoenix. As of Aug. 22, the Maricopa County Office of the Medical Examiner had confirmed 113 heat-related deaths in Maricopa County for 2026, more than triple the 35 confirmed at the same point last year. Another 584 deaths remained under investigation.
That reverses two consecutive years of decline. The county's most recent annual heat report identified 430 heat related deaths in 2025, the second straight year over year decrease, well below the record 645 recorded in 2023. Confirmed counts climb for months as reviews close, so the current figure will grow.
Recognizing the Signs That Separate Exhaustion from Emergency
Exertional heat stroke is defined by two things happening together: a core temperature above roughly 104 degrees and a clear change in mental status. Confusion, slurred speech, aggression, stumbling or collapse are the warning signs that matter most. Heat exhaustion tends to bring dizziness, nausea, heavy sweating, weakness and cramping without those neurological changes.
The distinction matters because treatment differs sharply. The Korey Stringer Institute at the University of Connecticut recommends adapting athletes to heat across a 10 to 14 day period, and research behind current cold water immersion protocols has shown a 100 percent survival rate when aggressive whole body cooling is started promptly and correctly.
Douglas J. Casa, the institute's chief executive officer and lead author of the National Athletic Trainers' Association position statement on exertional heat illness, said in the association's announcement of the position statement that heat stroke is "100 percent survivable if it is quickly and appropriately recognized and treated." He has also said these illnesses are largely preventable in organized sport when the right protocols exist, naming acclimatization, body cooling, and hydration.
Parents and coaches can act on that without waiting for the investigation to conclude. Anyone who becomes confused, stops making sense, or loses consciousness during exertion in heat needs 911 and immediate cooling, not a rest in the shade. Athletes arriving from cooler climates carry extra risk for two weeks. Early season sessions deserve shorter durations, enforced breaks and on site cooling equipment.
Arizona State has not given a timeline for its review, and no findings have been released.
Key Questions Answered
What happened to Matthew Mayich? The Arizona State defenseman collapsed during an outdoor team workout in Tempe on Aug. 20. He remains hospitalized in a coma, and his family's attorney says he has no chance of recovery.
Has any cause been confirmed? No. First responders were called for a reported heat-related illness, but no hospital or agency has confirmed a diagnosis. Arizona State says it is reviewing the workout.
Can a highly conditioned young athlete get heat stroke? Yes. Fitness does not prevent it. Risk rises with high intensity effort, inadequate breaks, dehydration and lack of acclimatization, which is why athletes new to a hot climate face elevated danger early on.
Which symptoms mean call 911? Confusion, disorientation, slurred speech, unusual aggression, stumbling, seizure, or collapse during exertion in heat. These changes distinguish heat stroke from heat exhaustion and require emergency care plus immediate cooling.
Why does acclimatization take so long? The body needs roughly 10 to 14 days of graded exposure to improve sweating efficiency, plasma volume, and cardiovascular response. Full intensity sessions before that adaptation carry higher risk.
Is heat risk rising in Phoenix? Confirmed heat-related deaths in Maricopa County more than tripled year over year as of late August, after two years of decline. Counts remain preliminary while reviews continue.
What should parents of student athletes ask about? Whether the program uses a graded acclimatization schedule, whether cooling equipment is on site, whether athletic trainers attend all sessions, and how water breaks are enforced.
