I'm a 31 year old male, 60kg 1.77meters. Don't smoke, rarely drink. Was gym active for 7 years until 3 months ago.
Since last year I've been having periods of lightheaded/faintness at my job (desk job), and gradually reduced aerobic ability at the gym. One year later and I can't do any type physical activity (walking, climbing stairs or even eating too much) without feeling breathless and very tired.