What Causes Shortness Of Breath And Weakness With Heavy Legs?

Hello my mother is 79 and has been staying with us from Ireland, on her return date she was feeling unwell, cold and very clammy to touch, short of breath, very tired and said her legs felt heavy, she was insisting on flying home as she did not want to lose flight money. I took her to chemist who said her BP was 91/90 but he said that was ok, it seemed a strange reading to me. She went for a check at her Doctors in Ireland who said she has irregular heartbeat and is setting up an appointment tomorrow at hospital. What do you think? She is also 5foot and weighs 11stone 6 pounds but is struggling to lose weight, she stopped smoking 2 years ago.her eye sight has deteriorated