The immune system and exercise

Question 1

increased URTI following marathon

Answer 1

Started from anecdotal evidence

Control – didn’t compete in particular event

Those who did marathon experienced minor illnesses

Question 2

URTI incidence and activity: moderate activity protects

Answer 2

1.5h day – moderate

40min 5x week – low

Moderate activity protects you

Slightly older women

Sedentary – 50% had infections

Question 3

how do we defend against pathogens: innate

Answer 3

what you are born with – first line of defence – activated as soon as you get ill

Anatomical barriers

Chemicals barriers

Immune cells

Question 4

how do we defend our body against pathogens: acquired

Answer 4

Specific

Previous exposure required

Develops with age

Cells

Question 5

immune cells

Answer 5

All WBCs

Phagocytosis – engulf foreign cells – destroy them from within

Question 6

exercise and circulating immune cells

Answer 6

Biphasic leukocytosis

1. Neutrophils and lymphocytes
2. Neutrophils

Lymphocytes below rest – open window for infection

Lymphocytopenia
• Fall in lymphocytes

Question 7

why does this happen during exercise? (changes in circulating immune cells)

Answer 7

Demargination – WBCs stuck to side of blood vessels during rest – increase in sheer stress – decrease likelihood of WBCs sticking to vessel wall

Increase in catecholamines – decrease likelihood of adherence

More immune cells in the blood

CO = cardiac output

Cortisol may not reach peak until after ex

Cortisol increases getting neutrophils from bone marrow – takes time to transport them – peak occurs later on

Question 8

open window hypothesis

Answer 8

More susceptible to infection

Question 9

neutrophil function

Answer 9

Phagocytosis –> de-granulation –> respiratory burst – markers of how well neutrophil functioning

Question 10

response to acute exercise: neutrophils

Answer 10

More but not as good at their job

Question 11

measure of do neutrophils work (training)

Answer 11

Before

Normal

Intense

Rest

Depletion of mature neutrophils – naïve neutrophils released – increase in number but reduction in how well they work

Question 12

acute exercise and neutrophils

Answer 12

Increase

Inhibit function

Question 13

immunity

Answer 13

Addition of cortisol prevents t cell proliferation

Start with naïve t helper cells

Where they go depends on infection type – virus/bacterial

Question 14

cell-mediated immunity after severe exercise

Answer 14

Acute severe activity (3km swim, 130km bike, 21km run) suppresses cell-mediated immunity

Question 15

cycling to fatigue: stimulate cytokine production

Answer 15

IFN-y production reduced following intense exercise

Question 16

stress hormones

Answer 16

More susceptible to infection when stressed

Question 17

practical advice

Answer 17

Minimise potential of transmission – avoid sick people

Don’t share water bottles

Avoid getting dry mouth – saliva good mucosal barrier

Be aware during training more at risk of getting ill – intense

Minimise risks of immunosuppression during intense training

Avoid too many long training sessions back-to-back

Monitor mood and emotions

Get adequate sleep

Question 18

exercising during infection

Answer 18

Ex tolerance reduced

Ex with infection may increase severity/duration of illness

Don’t train with fever with symptoms below neck (swollen glands, muscle/joint aches/cough) – create passage for infection to get around whole body

Don’t resume training at same level

Isolate infected team members from others

Question 19

what is a URTI?

Answer 19

Upper Respiratory Tract Infection

Question 20

innate response - anatomical barriers

Answer 20

Mucosal

Skin

Low pH of stomach

Question 21

innate response - immune cells

Answer 21

Granulocytes

Monocytes

Natural killer

• Destroy infection – kill host cells
• Responses non-specific – anything foreign

Question 22

cells in the acquired response

Answer 22

Cell-mediated
- Cytotoxic t-cells

Humoral
- Antibodies (B-lymphocytes)

Question 23

chronic exercise and neutrophils

Answer 23

Reduce function

Deplete bone marrow reserves – due to rise in cortisol

Question 24

eosinophil function

Answer 24

destroy parasites

Question 25

basophil function

Answer 25

inflammation

Question 26

lymphocyte function

Answer 26

immune response

Question 27

monocyte function

Answer 27

phagocytosis

Question 28

immediate response from the CNS

Answer 28

sympathetic nerves

increases noradrenaline and adrenaline

decreases neutrophil-endothelial adherence

increases HR and CO

increases blood flow through muscles and pulmonary circulation

increases release of leukocytes from spleen

increase in circulating neutrophils and lymphocytes

Question 29

delayed response from the CNS

Answer 29

hypothalamus

(CRF)

anterior pituitary

(ACTH)

adrenal cortex

(cortisol)

mobilisation of neutrophils from bone marrow