T13: Exercise and Immunity

the function of the immune system

protects the body from infectious disease. It is involved in tissue repair and protection against harmful pathogens.

2 types of immune system responses

innate

adaptive

innate immune system

bodys first line of defense against pathogens entering the body

present from before any exposure to pathogens and is effective from the day you were born

innate mechanisms in response to damage:physical

skin, tears, epithelial linings, mucosal secretions

innate mechanisms in response to damage:physical, skin

physical barrier preventing entry

slightly acidic pH(oils+ sweat) discourages growth of organisms

presence of antimicrobial peptides which prevent growth of harmful bacteria

innate mechanisms in response to damage:physical, tears

mucus in trachea traps pathogens

tears contain lysosomes which kill bacteria

also wash away irritating substances and microbes

innate mechanisms in response to damage:physical, epithelial linings

cillia, remove pathogens on epithelial linings in intestines protect body from intestinal bacteria

act as a physical barrier

secrete mucous to trap+ remove pathogend

innate mechanisms in response to damage:physical, mucous linings

sticky mucus traps pathogens which is wafted away by cillia

epithelial linings

body tissue that forms the covering on all internal and external surfaces of your body,

innate mechanisms in response to damage:chemical

pH of bodily fluids, hormones + other soluble factors

innate mechanisms in response to damage:chemical, pH of bodily fluids

pH 2 stomach to kill bacteria

saliva+ vaginal fluids slightly acidic to protect against harmful bacteria

innate mechanisms in response to damage:chemical, hormones

cortisol: short term, supresses inflamation but elevated levels over time can weaken immune system

studies suggest oestrogen enhance immune function, testosterone suppressive effect

innate mechanisms in response to damage:chemical, other soluble factors

cytokines: messengers between immune cells which regulate and co-ordinate a response

innate mechanisms in response to damage: leucocytes

white blood cells that fight disease

adaptive immune system

develops after exposure to microbes, toxins and any other foriegn objects

slow to react first time however quicker the next due to memory cells

3 mechanisms in the adaptive immune system

inflammation

clotting

lymphocyte and antibody production

3 mechanisms in the adaptive immune system: inflammation

when body detects primary defenses have been damaged and pathogens have entered the body histamine is produced

• dilates capillaries and increases permability in capillary walls

• may cause redness, swelling, pain and heat

3 mechanisms in the adaptive immune system: blood clotting

clot forms to close the wound + prevent pathogens from entering.

body sends white blood cells to area to fight off any potential infection resulting in formation of pus

3 mechanisms in the adaptive immune system: lymphocyte and antibody production

foriegn antigens are detected

lymphocyte produces antibodies which are specific to the antigens

these attack the antigen

phagocytes engulf antigen

some antibodies stay in the body as memorycells provoking a more rapid response upon reinfection

effect of intense training on the immune system

tissue damage, microtears leads to inflammation, production of leucocytes

effects of high + prolonged training on the immune system

decrease in innate and adaptive immune function

• drop in leucocytes compared to sedentary people

• sustained adrenaline and cortisol which spress immune system

which highlights the reletionship between exercise intensity and susceptability to disease

J curve

URTI= upper respiratory Tract infection

how do low levels of exercise affect immune function

low to medium immune function

• poorer circulation preventing free movement of cells and substances of the immune system preventing them from fighting infection

how do moderate levels of exercise affect immune function

high immune function

• better circulation, stronger hearts sllow free movement of cells and substances of the immune system increasing fight of infection

how do high levels of exercise affect immune function

very low

• lower leucocytes caused by stress of exercise

• inflammation of muscles due to exercise prevents blood flow and causes stress

• deeper breathing in exercise= more bacteria/viruses to be inhaled

• sustained increased levels of adrenaline and cortisol supress the immune system

how to minimise risk of infection among athletes

hygiene, rest, reletionships and diet

how to minimise risk of infection among athletes: hygine

reglar washing of hand/clothes/skin

limited hand/ mouth contact

oral hygiene

how to minimise risk of infection among athletes: rest

sufficient recovery+ sleep

incorporate sufficient recovery time into training programs

how to minimise risk of infection among athletes:diet

vitamins+ minerals

varied

pathogen free H2O