Allan Nascimento, a 34-year-old UFC flyweight from Brazil, was found unresponsive after an apparent heart attack in his sleep, just weeks after his most recent fight inside the Octagon.

A medical team responded and attempted to revive Nascimento but could not save him. He was pronounced dead at the scene, according to the UFC's official announcement. The organization posted a statement on X, the social media platform formerly known as Twitter.

Nascimento had last fought on June 20, a loss to Mitch Raposo. He carried a professional mixed martial arts record of 22 wins and 7 losses, with a 4-2 mark inside the UFC, Fox News reported. He earned two Fight of the Night bonuses during his time with the promotion, an award given to fighters who deliver the most exciting bout on a card.

A jiu-jitsu black belt who trained alongside Charles Oliveira

Nascimento trained at Chute Boxe, a well-known combat sports gym in São Paulo, Brazil. His training partner and fellow UFC fighter Charles Oliveira, a former lightweight champion widely regarded as one of the best submission artists in MMA history, posted an emotional tribute after learning of Nascimento's death.

Oliveira wrote on social media:

"Today I lost a brother that the fight game gave me. Thank you for always being by my side, for sharing the mats and the corner."

Nascimento held a black belt in Brazilian jiu-jitsu, a grappling discipline that forms the backbone of modern MMA ground fighting. His career spanned years of competition at the sport's highest level.

UFC expressed condolences but key details remain unknown

The UFC's official statement kept to broad terms. On X, the organization wrote:

"Our thoughts and deepest condolences are with Allan's family, friends, teammates, and loved ones during this incredibly difficult time."

No specific date, time, or location for Nascimento's death has been publicly confirmed beyond the UFC's disclosure that he was found unresponsive after an apparent heart attack in his sleep. The New York Post placed the discovery on Monday, August 3. Whether a medical examiner has formally ruled on the cause of death, or whether the "apparent heart attack" designation remains preliminary, is unclear from available reporting.

Nascimento was 34. A heart attack at that age in a professional athlete, someone whose conditioning and cardiovascular fitness are tested constantly, is uncommon enough to prompt hard questions. None of those questions have public answers yet.

For his teammates, his gym, and his family in Brazil, the facts so far are blunt and sparse: a young man went to sleep and did not wake up. The sport he gave his career to offered condolences. The rest is silence, for now.