Exercise and the Airway Flashcards
What causes airway remodelling?
Chronic endurance training
What does the layer of epithelium that covers the airway interior do?
Provides an internal barrier between inspired air and internal body structure
What is the most abundant cell type in the epithelium?
Ciliated respiratory epithelium
What can airway remodelling lead to?
Airway hyperresponsiveness
EIB
Asthma
Why does high level of ventilation cause?
Stress and dehydration of airways
What does EIB stand for and summarise it:
Exercise Induced Bronchoconstriction
Describes the short increase in airway resistance after vigorous exercise
Does EIB affect athletes?
Many athletes have it but it does not stop them from excelling
Can train to avoid it
What are the main causes of EIB?
Ventilation, water content and temperature of inspired air
What is the link between EIB and asthma (regarding athletes)?
EIB can be present without underlying asthma
Although EIB is common in asthmatics
What are the 2 theories of EIB?
Thermal
Hyperosmolarity
Explain the Thermal theory of EIB:
WATER LOSS BY EVAP FROM AIRWAY SURFACE Mucus cooling Vasoconstriction Vasc engorgement Vascular leakage EIB
Explain the Hyperosmolarity theory:
WATER LOSS BY EVAP FROM AIRWAY SURFACE Dehydration of mucus Inc Na, Ca, K Inc osmolarity Cell volume changes Mediators released Vascular leakage EIB
What is the preferred EIB theory and why?
Hyperosmolarity
Thermal doesn’t encompass mediator release
What are some EIB management strategies?
Taking glucocorticoids 10-15mins before exercise
Avoiding triggers (cold weather, pollution etc..)
Vitamins (C, B-Carotene)
Omega 3 reduces airway inflammation
What does the refractory period refer to?
A period whereby EIB magnitude is reduced for 1-4 hours in 50% of asthmatics
How does airway refractoriness work?
Pre-exercise warm up (whole body)
Desensitizes smooth muscle to bronchoconstrictive mediators
How does bronchoconstriction occur?
Airway surface liquid dehydration increases osmolarity, promotes releases of various inflammatory mediators
How can EIB be assessed?
Using direct and indirect tests
Describe the EIB direct test:
Induces direct contraction of airway smooth muscle using medications
Describe the EIB indirect test:
Induces contraction of airway smooth muscle by using exercise tests (mimics the sporting event)
How is EIB defined based on the test used?
Positive result occurs if post challenge FEV1 is at least 10% less than at basleine
What are some other breathing limitations in the healthy?
Breathing muscle fatigue
Expiratory flow limitation (occurs when tidal expiratory flow is above max expiratory flow
What is EFL and what does it cause?
Expiratory Flow Limitation
Causes dynamic hyperinflation, increases the work of breathing and likelihood of breathing muscle fatigue
