"The exercise, which began at 8.30, consisted of a six-kilometre cross-country trial, along the perimeter of the Lisbon Naval Base, and was overseen by 10 military personnel with a support vehicle,” Commander Fernando Fonseca said. “The cadet collapsed on reaching the fifth kilometre of the race. He was promptly attended by other cadets, by the monitors and by an officer who was on his own run and passed by at about 8.55."

A support car then took the cadet to the Naval Medicine Centre, where, according to Fonseca, "he was assisted by a medical team, who provided him with specialised assistance.” The regular ambulance service “INEM was also contacted and it promptly arrived at the location,” he added.

The cadet was subsequently transported to Lisbon’s São José Hospital, where efforts to resuscitate him continued, but it was not possible to save his life and he eventually died at about 10.40 a.m., according to the commander.

"The Navy has been providing all [possible] support, including psychological, to the cadet’s relatives and comrades,” Fonseca said. “In this moment of profound pain for the whole naval family, with the loss of one of our own, we send our most heartfelt condolences to his family and friends.”

The cadet was in his fourth year on a Naval Engineering course, specialising in arms and electronics, at the Naval School.