Chapter 11: Respiratory symptoms during exercise

INTRODUCTION

The respiratory system is critical to athletic performance. The integrity of this system results in the delivery of oxygen to the blood (and subsequently to both the exercising muscles and organs important for exercise, such as the heart) and the elimination of waste products such as carbon dioxide. Any dysfunction of these processes results in impaired performance. A number of medical conditions (such as asthma and respiratory infections) may affect performance.

COMMON RESPIRATORY SYMPTOMS

There are a number of symptoms with which an athlete may present that indicate the presence of respiratory disease. These include:

• (dyspnoea) shortness of breath

• wheeze

• cough

• chest pain or tightness

• lightheadedness.

Shortness of breath and wheeze

Some degree of breathlessness is a normal physiological response to exercise. Dyspnoea occurring during intense exercise may represent the reaching of maximal exercise and ventilatory capacity; however, particularly at lower-intensity exercise, it may represent an underlying respiratory or cardiac condition.

Breathlessness is a subjective symptom that can be defined as ‘an increased difficulty in breathing’. Despite the frequency of this complaint, the exact physiological mechanism is unknown. The most important cause from an athletic point of view is asthma, more specifically exercise-induced asthma (EIA) or exercise-induced bronchospasm (EIB). In the older athlete, especially with a history of smoking, chronic obstructive pulmonary disease (COPD) and cardiac ischaemia should be considered. More recently, vocal cord dysfunction (VCD), a condition characterised by paradoxical laryngeal movement, has become increasingly recognised. Dyspnoea may be classified clinically as acute, chronic or intermittent (see box).

Although the clinical history combined with the examination of the patient may indicate the likely cause of the dyspnoea, it is important to remember that the examination at rest is often normal. This is particularly seen in patients who are troubled by EIB, vocal cord dysfunction and cardiac ischaemia.

A musculoskeletal examination should also be performed to assess for the presence of thoracic stiffness or costochondritis.

Investigations

Respiratory function tests (e.g. spirometry) are required to further assess dyspnoea. Spirometry pre- and post-bronchodilator should be performed. A bronchial provocation challenge test should be performed in the case of normal or mildly abnormal spirometry, to assess for both the presence and severity of EIA/EIB.

If a cardiac cause is suspected, an exercise ECG and echocardiogram are required, often combined in a stress echocardiogram. A chest X-ray may be required if clinical suspicions of a respiratory tract infection, cardiac failure, carcinoma, COPD or a pneumothorax arise.

Blood tests, in particular the haemoglobin level and iron studies, may be required to exclude anaemia or ...