Matsuda had regularly undergone health checks and his most recent tests in January had detected no irregularities.
Normally heart attacks like the one that claimed the life of the man who played 40 games for the national team are more likely to occur in those from their 40s to 50s onward, with greater risk among those with high blood pressure, high blood fats, diabetes, the obese and smokers.
“He never smoked and lived a normal lifestyle,” said Takashige Momose, Matsumoto Yamaga’s team doctor. “Considering the weather and temperature on the day of his heart attack, it’s hard to consider it may have been brought about by dehydration.”
Haruki Ito, deputy head of the Sakakibara Heart Institute, called Matsuda’s death “a rare case.”
Matsuda’s career with the national team included the 2002 World Cup in Japan and South Korea. He also played 385 J-League games for the Yokohama F Marinos from 1995 to 2010, helping the team to three league titles.
Matsuda collapsed after a 15-minute training run on Tuesday. After an initial diagnosis of heat stroke, he was later confirmed to have had a heart attack. He was unconscious on his arrival at the hospital and showed no response to heart massage.
Matsuda joined third-tier club Matsumoto Yamaga this year after spending his entire J-League career with Yokohama.