Exercise and the Airway

Question 1

What causes airway remodelling?

Answer 1

Chronic endurance training

Question 2

What does the layer of epithelium that covers the airway interior do?

Answer 2

Provides an internal barrier between inspired air and internal body structure

Question 3

What is the most abundant cell type in the epithelium?

Answer 3

Ciliated respiratory epithelium

Question 4

What can airway remodelling lead to?

Answer 4

Airway hyperresponsiveness
EIB
Asthma

Question 5

Why does high level of ventilation cause?

Answer 5

Stress and dehydration of airways

Question 6

What does EIB stand for and summarise it:

Answer 6

Exercise Induced Bronchoconstriction

Describes the short increase in airway resistance after vigorous exercise

Question 7

Does EIB affect athletes?

Answer 7

Many athletes have it but it does not stop them from excelling
Can train to avoid it

Question 8

What are the main causes of EIB?

Answer 8

Ventilation, water content and temperature of inspired air

Question 9

What is the link between EIB and asthma (regarding athletes)?

Answer 9

EIB can be present without underlying asthma

Although EIB is common in asthmatics

Question 10

What are the 2 theories of EIB?

Answer 10

Thermal

Hyperosmolarity

Question 11

Explain the Thermal theory of EIB:

Answer 11

WATER LOSS BY EVAP FROM AIRWAY SURFACE
Mucus cooling
Vasoconstriction
Vasc engorgement
Vascular leakage
EIB

Question 12

Explain the Hyperosmolarity theory:

Answer 12

WATER LOSS BY EVAP FROM AIRWAY SURFACE
Dehydration of mucus
Inc Na, Ca, K 
Inc osmolarity
Cell volume changes
Mediators released
Vascular leakage
EIB

Question 13

What is the preferred EIB theory and why?

Answer 13

Hyperosmolarity

Thermal doesn’t encompass mediator release

Question 14

What are some EIB management strategies?

Answer 14

Taking glucocorticoids 10-15mins before exercise
Avoiding triggers (cold weather, pollution etc..)
Vitamins (C, B-Carotene)
Omega 3 reduces airway inflammation

Question 15

What does the refractory period refer to?

Answer 15

A period whereby EIB magnitude is reduced for 1-4 hours in 50% of asthmatics

Question 16

How does airway refractoriness work?

Answer 16

Pre-exercise warm up (whole body)

Desensitizes smooth muscle to bronchoconstrictive mediators

Question 17

How does bronchoconstriction occur?

Answer 17

Airway surface liquid dehydration increases osmolarity, promotes releases of various inflammatory mediators

Question 18

How can EIB be assessed?

Answer 18

Using direct and indirect tests

Question 19

Describe the EIB direct test:

Answer 19

Induces direct contraction of airway smooth muscle using medications

Question 20

Describe the EIB indirect test:

Answer 20

Induces contraction of airway smooth muscle by using exercise tests (mimics the sporting event)

Question 21

How is EIB defined based on the test used?

Answer 21

Positive result occurs if post challenge FEV1 is at least 10% less than at basleine

Question 22

What are some other breathing limitations in the healthy?

Answer 22

Breathing muscle fatigue

Expiratory flow limitation (occurs when tidal expiratory flow is above max expiratory flow

Question 23

What is EFL and what does it cause?

Answer 23

Expiratory Flow Limitation

Causes dynamic hyperinflation, increases the work of breathing and likelihood of breathing muscle fatigue