A mobile phone application will be used to collect data during daily life among people who experience breathlessness. Breathlessness is the subjective sensation of breathing discomfort, is common and appears in the daily life of people with cardiorespiratory diseases. Physicians often rely on patient’s history based on symptom recall. The relation between recalled and experienced breathlessness is still poorly understood. This study aims at evaluating the relationship between experienced breathlessness and recalled breathlessness and predicted future breathlessness.