Gael Mackinnon, a part-time barmaid who was studying at Edinburgh University, collapsed on Sunday morning after a night out with friends.
Sister Dawn, 24, broke the news of the tragedy to friends on Facebook, writing: “She died after a heart attack. I can’t express how amazing she was. Many thanks for everyone’s support, she was truly loved by everyone.”
Just two days earlier, Gael had been reunited with brother, Euan, after he returned from a spell living in Australia. It was the first time the three siblings had been together in recent years.
On Friday, Gael wrote on her Facebook page: “Off to get Euan Mackinnon at the airport.”
The sport science student, from Bathgate, West Lothian, grew up on a farm, and attended the Rudolf Steiner School in Edinburgh. She was found dead at her flat in Elm Row.
Brenda Henderson, manager of the Southsider pub in Newington, said Gael hadn’t taken a day off sick for four years.
She said: “She was just the most gorgeous barmaid, very bubbly and so loved by every member of staff and customers.
“We always said she was the most gorgeous barmaid at the Southsider, but she was also hard working and reliable – if anyone needed a shift covered, she would be the first person I asked.”
Ms Henderson said Gael had been a fitness fanatic and that her death had come as a huge surprise.
“We are still in a complete state of shock. She was very healthy,” she said. “Gael used to jog around Arthur’s Seat every day and planned to take part in the Moonwalk this year.
“She also enjoyed practising her sports massage skills on other members of staff.
“It is really sad because, before she died, she was the happiest I had ever seen her. When she didn’t turn up for work on Sunday it was the first time she had missed a shift and I was just so shocked when her aunt called us to say what had happened.
“Gael was really enjoying her sport therapy course at Edinburgh University and also loved being on her family’s farm.”
Friends have been paying tribute on Facebook since the news broke.
Connor Stewart said: “I’m really going to miss your cheery attitude to life, you were such a hard-working person and still managed to stay smiling no matter how hard your busy life got.”
Evelyn Jellema, who had known Gael since her school days, said: “I am devastated that the world has taken such a wonderful life from us, you were the kindest, sunniest person I have ever had the privilege to know and I will miss you more than words can say. Love you always and forever more, rest in peace.”
Rachel Barr added: “My beautiful friend, I can’t believe that you are gone. I’m completely devastated and can think of nothing to say other than that I have a million things I wanted to tell you.”
Lothian and Borders Police said there had been no suspicious circumstances behind Gael’s death.
A spokesman said: “Police are investigating after a 22-year-old woman was found dead within her Elm Row flat on Sunday, May 13.
“There are no suspicious circumstances surrounding her death and a report has been sent to the procurator fiscal. Her family have been fully informed as to the progress of this inquiry.”