Allan Nascimento had six fights in five years with the UFC [Getty Images]Mixed martial arts fighter Allan Nascimento has died at the age of 34, says the UFC.According to MMA's leading promotion, the Brazilian flyweight was found unresponsive on Monday morning after suffering an apparent heart attack in his sleep."Despite the efforts of the responding medical team, he was pronounced deceased at the scene," added a UFC statement."Our thoughts and deepest condolences are with Allan's family, friends, team-mates and loved ones during this incredibly difficult time."Nascimento had been with the UFC since 2021 and his last fight was a split-decision loss to Mitch Raposo in June.That left Nascimento with an overall MMA record of 22 wins and seven losses, with a 4-2 record in the UFC.Nascimento trained at Chute Boxe under coach Diego Lima in Brazil, and was a training partner to former UFC champion Charles Oliveira, UFC lightweight Elves Brener and more.Oliveira posted a tribute to his friend on social media."Today I lost a brother that the fight game gave me," he said on Instagram."Thank you for always being by my side, for sharing the mats and the corner. "I have nothing but gratitude for having you with me in training, in the corner, and just hanging out. I love you, man; you're a legend."MMA schedule and results 2026Watch every Born to Brawl episode More MMA from the BBC Notifications, social media and more with BBC Sport