Is dyspnoea worth documenting and accurately assessing? The answer is undoubtedly yes, for at least the following reasons. 1) Activity-related dyspnoea is usually the earliest and most troublesome complaint for which patients with cardiopulmonary diseases seek medical attention. 2) This symptom progresses relentlessly as the underlying disease advances, leading invariably to avoidance of activity with consequent skeletal muscle deconditioning and an impoverished quality of life. 3) It is estimated that up to a quarter of the general population and half of severely ill patients are affected by it. 4) Dyspnoea is also an important predictor of quality of life, exercise tolerance and mortality in various conditions. In patients with chronic obstructive pulmonary disease (COPD), it has been shown to be a better predictor of mortality than forced expiratory volume in 1 s. In patients with heart disease referred for clinical exercise testing, it is a better predictor of mortality than angina. 5) Dyspnoea is also associated with decreased functional status and worse psychological health in older individuals living at home. 6) It is also a factor in the low adherence to exercise training programmes in sedentary adults and in patients with COPD. 7) The effective management of exertional dyspnoea remains a major challenge for caregivers and modern treatment strategies that are based on attempts to reverse the underlying chronic condition are only partially successful [1–7].