Amateur gymnast Rosie Connolly collapsed and died after going for a swim - just one hour after rushing to the aid of a fellow gym user . A talented amateur gymnast collapsed and died after going for a swim - just one hour after rushing to the aid of a fellow gym user. Rosie Connolly, 21, a receptionist at the Laboratory Spa in Mill Hill - used by Olympics stars Anthony Joshua and Mark Foster - fell unconscious at the poolside after a swim. She had told staff she had felt unwell in the water and reportedly struggled to clamber out of the club pool. Two doctors battled to revive her as an ambulance crew arrived and took her to Barnet General Hospital. But the popular worker at the spa died shortly afterwards, following a suspected cardiac arrest. Just 50 minutes before the tragedy, Miss Connolly - a member of Childs Hill gymnastics club -  had rushed to help a club member who became ill in the changing rooms and had cared for them until an ambulance had arrived. The Laboratory Spa has opened a book of condolence. A colleague said: 'Everyone knew her here and loved her. She was a bubbly, smiley person and will be incredibly missed.' A club member added: 'Everyone was shocked to find out what happened to Rosie. She had her whole life in front of her. She was a lovely, hard-working girl who was always able to answer questions with a smile. She made people feel welcome.' Friends paid tribute to Miss Connolly, a member of Childs Hill gymnastics club who had performed in an international competition in Switzerland. Rosie's sister Hayley, 27, said at the family's home near the club that the family were too upset to talk about the death, the Evening Standard reported. She said : 'It's too raw for us.' Alexandra, a nurse, wrote: 'I can't believe it, my fellow dancer, the only one I truly trusted to pick me up without dropping me. You'll be missed, you beautiful girl.' Panayioda Kilikita, a trainer at the club, wrote on Facebook: 'Oh our beautiful Rosie why did you get taken? You are loved dearly and will be forever missed.' Sinead McKenna added: 'What an amazing, beautiful, kind-hearted little star you are Rosie.' Connolly, 21, a receptionist at the Laboratory Spa in Mill Hill - used by Olympics stars Anthony Joshua and Mark Foster - fell unconscious at the poolside . Just 50 minutes before the tragedy, Miss Connolly - a member of Childs Hill gymnastics club - had rushed to help a club member who became ill in the changing rooms and had cared for them until an ambulance had arrived .
Rosie Connolly, 21, was receptionist at the Laboratory Spa in Mill Hill . She told staff she felt unwell and 'struggled to clamber out of pool'
Two doctors battled to revive her as an ambulance crew arrived . The popular worker died shortly afterwards, of a suspected cardiac arrest .