"They told me that it was not possible [to have minute's silence] because not a minute could be wasted," Alvarez told local media after the race.
"It's something that has affected us all, but maybe because of the distance and because I have family there... I really think it would have been a good thing to do.
"So I started a minute later. But I do not mind, I have a feeling worth more than if I win all the gold medals in the world."
A number of people took to social media to applaud Alvarez for his selfless personal tribute to the victims of Thursday's attack.
"Fernando Alvarez should be awarded a Gold medal for showing such respect for victims of Barcelona attack. Bravisimo!!" wrote one user.
"All his teammates, like his Club feel very proud of him, we want to congratulate him for being a great person!" Alvarez's swimming club wrote in a post on their club page.