W4 - Exercise & Immune Function Flashcards
Describe the relationship between amount of exercise and susceptibility to illness
How was this shown by illness levels at London 2012 Olympics?
- Too much exercise can wear a person out, causing above average risk of infection
- Screening of 10 568 athletes (should be at peak fitness & health)
- 72 illnesses per 1000 athletes
- Infection was 46% source of illness
- Respiratory system was commonly affected (2 in 5 of all cases of illness)
- Then digestive system (~1 in 6 of all cases of illness)
○ Then due to open food café (ill from overeating, undereating, changing eating habits)
For the average person… Does activity reduce their susceptibility to illness?
Describe the results shown by the study that showed this during the winter:
YES,
- General PA reduces the risk of RI(respiratory infections)
- Study of >1000 men and women aged 18-85
- Monitored over one winter(when infections are most likely)
- Infection symptoms were related to activity level and perceived fitness
- People that are more active recover quicker & the infections are less severe
- Little difference between results of medium & highest fitness levels
How does moderate-vigorous activity effect a person’s susceptibility to illness?
- meta-analysis of 500,000 people
- MVPA is associated with 31% lower risk of community-acquired infectious diseases
- 37% reduction in risk in infectious disease mortality
Why is infection detrimental to elite athletes?
By what percentage is success reduced for every week of incomplete training?
“You can’t train if you are always sick” - Martensson, Nordebo and Malm. J Sports Sci Med (2014).
- Affects performance goals as elite athletes that are sick cannot make training - More tolerant to illness, so elite have a slightly lower risk
- Incomplete training for every week reduces athletes chance of success by 26%
What are the 2 groups of white blood cells involved in the 1st line of defence?
What is the non-specific response?
What is the specific response?
- macrophages & granulocytes
–> 1st line of defence, kicks in immediately when comes into contact with an agent, innate(from birth) - Non-specific - responds the same no matter what the agent is (activated very quickly)
- monocytes/macrophages tell the adaptive cells what they are dealing with
○ Allows lymphocytes to get ready - Acquired & specific:
○ Adapts to whatever you are exposed to - learns best way to deal with it
○ subpopulations of lymphocytes are tailored to the certain receptors - if contact made with the same agent again, acquires memory deal with it - causes glands to swell up
Where are the T cells created?
- what response do they elicit
Where are the B cells created?
- what response do they elicit
- thymus
- cell-mediated response
- bone marrow
- humoral response
Describe the cell mediated response of Tcells
What role do THelper cells play?
What is the role of Tregs?
Cell-mediated response - Tcells are responsible for making copies of themselves
- Helper Tcells are the first contact cells for an agent
- Decides & control the subsequent anti-viral response
- Tregs prevent an immune response that is overactive, preventing cells attacking themselves
- Both these cells form memory of how they dealt with, in case a person comes into contact with the same cell again
What is the job of Cytotoxic Tcells?
T-cytotoxic cells(killing Tcells):
- Destroy infected cells by inserting pore forming molecules (‘perforins’/pins) into the infected cell membrane, causing it to lyse(insides come out)
- Cytotoxic t-lymphocyte - A specialized white blood cell responsible for eliminating unwanted body cells (e.g.: cancer) is killing a cell infected with the influenza
Explain the role of Bcells
Bcells become bigger and mature into plasma cells, secreting antibodies(Ig)
- When binds to antigen, it is specific to that illness
- Antibodies floats around in tears, blood, sweat
- Antibodies recognise certain shapes of antigens(therefore bind to them) - this also creates a signal to other immune cells(flag)
- This is the theory behind booster injection(memory Bcells)
Describe how aerobic exercise is related to naïve cytotoxic Tcells (CD8)
Aerobic fitness was positively related to proportion of naïve cytotoxic (CD8) T cells
- 100 men aged between 18-61
- Naïve(ready for action) not come into contact with agent before
- Aerobic training was positively related to number of naïve cells(above average = more active)
○ Therefore should be better at dealing with illness
How is aerobic exercise related to the number of exhausted THelper cells (CD4)?
Aerobic fitness was negatively related to the proportion of exhausted T helper (CD4) and cytotoxic (CD8) cells
- Grown and divide too many times(useless)
- Above average fitness for their age had fewer shattered Tcells
How does regular PA impact a person’s ability to proliferate Tcells?
- Ability to proliferate is much higher in people that have been active for >5years
- More active lifestyles
What is IgA?
How does exercise impact the level of IgA a person has?
IgA(immunoglobulin A) found in saliva, is first immune response to infectious agents
○ IgA is associated in a lot fewer severe symptoms days
- Illnesses are mainly through inhaling/swallowing
- Those in 12 week training study had more IgA in saliva
- Game seasons had most suppression in the defence against respiratory infection
- Seasons when IgA was lowest, when training was the highest = players has the highest rate of infection
How does training load affect the amount of anti-viral Tcells?
- Anti-viral interferon gamma Tcells
- Period of intense training greatly lowers anti-viral Tcells
What are some factors which increase a person’s risk of infection?
What are some ways to resolve this?
All stress, bad diet and lack of sleep supress immune function
All immune cells need a sufficient source of energy
To reduce chances of infection we can:
- Reduces number of pathogens we are exposed to
- Increase immune function(recovery)
- Increasing hygiene can prevent illness
- Do not share utensils, drinks bottles
- Isolate people that are infected quickly
