Respiratory Response to Exercise

not

in healthy individuals respiration is ____ a limiting factor of exercise

increased

during short term light to moderate exercise there is an ____ PO2 gradient due to oxygen in muscle tissue being used

increased

during short term light to moderate exercise there is ____ PCO2 which shifts the oxygen dissociation curve to the right allowing more O2 to be released at a given pressure vs. resting conditions

decreased

during short term light to moderate exercise pH is ____ which also shifts the oxygen dissociation curve to the right based on how much H+ is present

increased

during short term light to moderate intensity exercise temperature is ___ which shifts the oxygen dissociation curve to the right

unload

when the oxygen dissociation curve is shifted to the right Hb will ____ more O2 (15% more at the same PP)

- efficiency

hold

when the oxygen dissociation curve is shifted to the left Hb will ____ on to more O2

VT1

upper cutoff of moderate intensity (75% of VO2max)

after this exercise is considered high intensity

VT2

transition to heavy non-sustainable intensity (85-90% VO2max)

beyond maximal aerobic capacity

EIAH

PaO2 can decrease 18-38 mmHg below resting

reduces VO2max by 1.5-2% for each 1% reduction in SaO2%

- after initial 3% decrease in SaO2%

EIAH

this phenomenon occurs in

- highly trained, healthy, elite male cyclists and runners with VO2max > 4.5 L/min or 55 ml/kg/min (at 60-90% VO2max)

- female elite athletes

- young and old athletes of both sexes

- untrained, low fit females

- non elite athletes following high intensity interval training

adapt

EIAH athletes ____ to extract more O2 at level of working muscle

therefore external respiration may be the limiting factor in these athletes

poorer

if someone experiences EIAH at sea level they will have ___ performance at altitude

EIAH causes

excess increase in A-a PO2 diff

-non-uniformity in alveolar ventilation and cardiac output distribution

-extrapulmonary and intrapulmonary shunts where RBCs don't come into contact with O2 or deoxygenated blood is dumped into left side of heart

-mechanical contraints on airflow or insensitivity to the ventilatory stimuli associated with exercise

alveolar-capillary diffusion disequilibrium

- alveolar-capillary surface area

- diffusion gradient from alveolar to capillary PO2

- time available for equilibrium in the pulmonary capillary (not enough time to fully saturate blood)

ventilation-perfusion inequality causes: edema/extravascular water accumulation, faster movement of RBCs through capillaries, lack of further increase in pulmonary capillary volume

metaboreflex

accumulation of metabolites within the skeletal muscles activate afferent neurons and send signals to the brain

increases sympathetic vasoconstriction in exercising muscles

decreased BF = decreased O2 extraction = peripheral muscle fatigue/increased RPE/decreased exercise performance

pressure

another respiratory limitation to exercise is excessive fluctuations in intrathoracic ____

excessive positive intrathoracic pressure decreases SV and thus decreases Q

typically >85% VO2max (really high intensity)

coupling

locomotor-respiratory ____ during exercise (entrainment)

timing breathing with movement

may reduce work of breathing

may delay onset of respiratory muscle fatigue and/or improve respiratory efficiency

- subconscious, not everyone does this

Females

these characteristics describe males/females?

- lower lung volumes/capacities

- similar max RR

- higher RR and lower VT at the same submax ventilation

- lower max VE

- smaller airways relative to lung size (increased resistance)

- more likely to have expiratory flow limitations

- more likely to demo increased elastic load on inspiratory muscles

- experience breathing to be more work and O2 consuming

- higher A-a PO2 diff

- lower PaO2

- slightly lower PaCO2

children

these characteristics describe ____

- lower lung volumes/capacities (smaller lungs)

- higher frequency and VE

- pulmonary ventilation similar to adults; PCO2 set point is lower

- response to exercise: tend to hyperventilate compared to adults

older

for ____ adults their TLC may stay the same or decrease

VC and IC decrease

RV and FRC increase

FEV1 and MVV decline steadily after 35 years old

in older ____ their absolute VE is higher at any given work rate compared to young adults

VEmax is lower (absolute and relative)

VD/VT is 15-20% higher (increased VD, tissue elasticity, perfusion of alveoli)

expiratory flow limitations which worsen with increasing exercise intensity

ventilatory breakpoints occur at lower absolute and relative workloads

lower; similar

older adults have ____ PaO2 at rest but ____ PAO2

greater

older adults have a ____ difference of A-a O2 difference

decreases

in older adults saturation of Hb ____ 2-3% from age 10-70

similar

during exercise older adults have ____ PaCO2 and PaO2

greater; lower

in older adults a-vO2 diff is ____ at rest and submax exercise but SvO2% is ____