exercise

Question 1

how does the human body perform exercise

Answer 1

muscle driver - consumes O2 and makes CO2
circulatory system
lungs
anaerobic metabolism/acidosis

Question 2

Purpose of GE

Answer 2

Transport O2 to tissues

main aim removal of CO2

Question 3

Respiratory quotient

Answer 3

CO2 production/O2 consumption
=1 = 1 CO2 for every O2
lipid RER 0.7 - more O2 for less CO2 - lung doesn’t have to work as hard
protein RER = 0.8
when RER>1 - anaerobin resp make CO2 but not using O2
RER in mouth
Rq cellular level

Question 4

Flow of O2 and CO2

Answer 4

cog system
muscle produce CO2
cause CO2 flow through heart and blood and then expired
-ve pressure in chest - draw air in - dissolve into blood bound to Hb - through capillaries to tissues, CO2 goes the other way

Question 5

Role of O2 in resp

Answer 5

required for the production of energy

Question 6

Oxygen requirements

Answer 6

seated at rest need 3.55ml/min/kg of O2 
goes up in metabolic equivalents (MET) 
standing 1.5MET
walking 2
cycling >4 
running >7

Question 7

Muscles response to exercise

Answer 7

use stored energy - ATP and creatine phosphate for muscle contraction
inorganic phosphates, ADP and creatine drive ox phos
TCA and glycolysis increase
ox consumption increase at muscle
initially CO2 production only slightly increases - buffered as HCO3- then rises matching O2

Question 8

O2 and CO2 levels in exercise

Answer 8

O2 increases 10ml/min/watt
build up deficit - need to pay back at end as O2 debt
in CVD - longer for blood to reach lung = larger debt
CO2 rises more slowly - more soluble so even though it is produced it is stored in tissues

Question 9

Circulation response to incremental exercise

Answer 9

resting CO = 5L/min
almost linear increase in CO
plateau - body deliver as much O2 as it can - define max work load
O2 consumption limited by CO
O2 consumption increase linearly with the workload
anaerobic respiration contribute to small and inefficient part of metabolism
to increase O2 delivery - increase CO to max then HR
SV decrease as HR increase past point - filling time less

Question 10

max HR

Answer 10

220-age

Question 11

Oxygen consumption

Answer 11

increase in O2 consumption is double increase in CO
double O2 delivery = quadruple O2 consumption - because bigger conc grad, O2 diffuse more down, ODC facilitates this
mixed venous saturation drops from 75-80% at rest to 15-20% in exercise
up to 85% O2 can be extracted in exercise

Question 12

Fick eqn

Answer 12

Oxygen consumption = Cardiac Output x (a-v) O2 Content

Question 13

Lung response to incremental exercise

Answer 13

hyperventilate increases tidal vol
when reach max vol - increase the frequency
inefficient to breathe at vital capacity - roughly breathe at half
CO2 production drive ventilation
linear increae in ventilation for CO2 production
arterial PCO2 stays the same - so pH stays the same

Question 14

VQ matching in exercise

Answer 14

at rest not ideal - PAO2 and PaO2 don’t match

early exercise - VQ improves PaO2

Question 15

incremental aerobic respiration

Answer 15

aerobic respiration - O2 flow matches demand
RQ rises to 1 as glucose becomes the predominant fuel source
ventilation increases to match CO2 production and attempts to maintain steady state

Question 16

Anaerobic metabolism

Answer 16

inefficient
central to human exercise physiology
short term solution when higher energy required

Question 17

Bohr effect

Answer 17

extract more O2 - diffusion effect

when generate lactic acid - Hb affinity for O2 decreases - offload more

Question 18

dealing with acidosis

Answer 18

lactate produces H+
buffered by bicarb 
HCO3- + H+ -- H2CO3 -- CO2 +H2O
increased CO2 
increased ventilation 
pH relatively stable 
H+ exceeds HCO2- 
hyperventilation relative to VCO2

Question 19

why does hyperventilation in exercise cause exercise intolerance

Answer 19

causes low CO2 and high pH

O2 not released to muscles

Question 20

what happens to VE, VCO2, VO2 in anaerobic resp

Answer 20

become acidotic and outstrip buffer
hyperventilate - sharp, non-linear increase in VE
get rid of more CO2 than make
more CO2 produced than oxygen consumed

Question 21

QO2/CO2

Answer 21

at muscle

Question 22

VO2/CO2

Answer 22

at mouth

Question 23

VE

Answer 23

minute vent

Question 24

PAO2/CO2

Answer 24

Alveolar partial pressure

Question 25

PaO2/CO2

Answer 25

Arterial partial pressure

Question 26

breathing times

Answer 26

35 second expiring
25 second inspiring
therefore max expiration/min = 35 x FEV1

Question 27

why measure vital capacity in a breathing test

Answer 27

know max HR and ventilation
know what is limiting the person
normally at peak CO - still have 30% breathing reserve left
however - if do more exercise, you can consume more O2 - more go into breathing reserve, this could match CO

Question 28

oxygen pulse

Answer 28

O2 consumed per heart beat - proportional to SV (consume more O2 each beat if beat bigger) and O2 extraction

Question 29

why is RER lower than expected when 1st on bike

Answer 29

overthink breathing - hyperventilate
blow off CO2
= lower RER

Question 30

interpreting the VE VCO2 relationship

Answer 30

ventilation increases with CO2 production
want it to be in or below lines on graph - otherwise inefficient
inefficient because of dead space/excessive hyperventilation

Question 31

how do you calibrate the equipment

Answer 31

biological control

if get the same result over the same work load - probably calibrated