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Exercise Immunology - Can we exercise too much? - Coggle Diagram
Exercise Immunology - Can we exercise too much?
How can we measure immune function?
Self-reported illness
Upper respiratory tract infections (URTI's) - number and severity.
Cellular level
Concentration
of specific cell types (T-cells, B-cells or neutrophils)
Activation/suppression markers
on a specific cell types.
Measure immune cell
function
(e.g., movement of immune cells towards bacteria or virus).
Release of molecules reflecting immune response
Antibodies with anti-microbial properties
Enzymes with a role in phagocytosis.
Physical Activity vs. Number of Infections
(Matthews et al., 2002)
Levels of PA in healthy adults (age 20-70 yrs, N = 547) measured 5 times over 12 months.
Participants split into 4 groups based on
activity levels
(METs: Q1 - Q4)
Number of self-reported
upper respiratory tract infections (URTIs)
compared relative to Q1 group.
29% lower URTI risk in Q4
compared to Q1 (p < .01)
Overview of benefits of exercise on immunity
Cells mobilized into the blood during exercise have
high function
and
tissue homing potential
.
These cells have the highest capacity to
leave the circulation
.
Innate Immunity and Exercise
(Kawanishi et al., 2010)
Exercise-induced
muscle tissue injury
elicits a strong
innate immune response
involving neutrophils, monocytes and macrophages.
These cells
release proteins
that initiate, mediate, and terminate muscle repair by modulating processs such as, migration, muscle fibre breakdown and regeneration, and anti-microbial defense.
Regular exercise promotes an anti-inflammatory phenotype in skeletal muscle. This comes from the repeated release of
myokines
e.g., IL-6, IL-7, IL-15, and IL-10.
Marathon Runners and Increased Infection Risk
(Neiman et al., 1990)
"Of the 1,828 LA Marathon participants without infectious episode (IE) before the marathon, 236 reported IE during teh week following the marathon vs. 3 of 134 similarly experienced runners who did not participate.
These data suffuse that runners may
experience odds for IE during heavy training or following a marathon race
Moderate vs Heavy Training Loads
Moderate amounts of exercise
enhance immune function
Some researchers content that heavy exercise levels of periods of
intensified training
can
impair immune function.
Intense exercise impacts resting and exercise-induced changes in immunity
(Lancaster et al., 2004)
Participants undertook 3 exercise trails to exhaustion, with blood samples drawn before, immediately and 1-hour post-exercise.
Trial 1
- done at baseline (day 1)
Trial 2
- undertaken following a 6-day period of intensified training (day 8)
Trial 3
- undertaken following 2-weeks of recovery (day 23)
Heavy Exercise and Immune Function
T-cell migration (movement) and growth (proliferation) were measured before and after a prolonged (2-hour) bout of exercise (60% of VO2max)
T-cell migration and proliferation were "impaired" following intesne exercise.
Non-Exercise Factors
Increased
ventilation rates
causing localized airway damage from e.g., cold air exposure - not an infection, but feels-like and self-reported as one.
Genetic variation in critical genes that modulate immune defense (i.e., HLA region).