Chapter 6: Exercise & the Immune System Flashcards
mechanisms of defense of the innate immune system
phagocytosis, apoptosis, complement, and acute inflammation
define phagocytosis
ingestion of bacteria by macrophage and neutrophils
define apoptosis (innate)
natural killer cells destroy tumor and virally infected cells by programmed cell death
define complement
complement proteins tag surface of bacteria and destroy it by creating pores in surface
define acute inflammation
pathogen activates immune cells within injured tissue, including “alarm” cells (macrophage , neutrophils)
mechanism of acute inflammation
“alarm” cells trigger vasodilation and increased vascular permeability —> increased blood flow to injured area —> inflammation
define sterile inflammation
inflammation in the absence of any pathogen
define chronic inflammation
due to persistent infection or prolonged immune response
what is low grade chronic inflammation caused by
inactivity, obesity, aging
what is high grade chronic inflammation caused by
certain cancers and rheumatoid arthritis
role of B cells (plasma cells)
secrete antibodies that tag pathogen for destruction
role of cytotoxic T cells
kill virally infected cells
role of helper T cells
secrete cytokines that enhance immune response
role of regulatory T cells
prevent immune system from attacking normal body antigens
what kind of exercise is shown to improve immunosurveillance
acute moderate exercise (40-60% VO2 max) < 60 mins
moderate intensity / short duration
how does acute moderate exercise boost immunosurveillance? when does it return to normal?
boosts innate and adaptive immune system, returns to normal after about 3 hours
what type of exercise has a depressive effect on immune system?
prolonged exercise (> 90 mins)
high intensity / long duration
How does acute prolonged exercise depress the immune system?
decreases levels of B cells, T cells, and natural killer cells
decreases natural killer cell activity and T cell function
decreases nasal neutrophil phagocytosis
decreases nasal and salivary IgA
increases pro and anti inflammatory cytokines
what is the relationship between chronic exercise workload and UTRI risk?
J curve model, too little is normal risk, too much is higher risk
how does continuous moderate aerobic exercise protect against infection?
regularly boosts immunosurveillance, and has associative factors (less emotional stress, better nutrition, adequate sleep)
describe the “open window” concept
window after high-intensity / long-duration aerobic exercises where an individual is at an increased risk of infection because of a depressed immune system
does exercising in a hot environment impair immune function?
no, even though we see an increase in cortisol compared to a cold environment, it is not enough to elicit a depressive immune response
does exercising in a cold environment have an effect on the immune system?
no
does exercising at a high altitude have an effect on the immune system?
yes, we see increased levels of cortisol and in the field, increased risk of URTI
