6: cardiorespiratory endurance Flashcards
what is the breathing rate at rest?
12-20 breaths/minute
What is the heart rate at rest?
50-90 beats/min
What is the cardaic output at rest?
5L/min
What is blood distribution to muscles at rest?
15-20%
during exercise what is the breathing rate
40-60 breaths/min
During exercise what is the heart rate?
170-210 beats.min
What is the cardiac output during exercise
25L/min
What is the percentage of blood distributed to muscles durign exercise?
85-90%
Ventilation
increases with exercise to meet the increased demand of gas exchange
during exercise; ventilation can increase from 6L/m at rest to over 150L/min during maximal exercise and to more than 200L/min during maximal voluntary breathing
with exercise/endurance training, the lungs become more efficient in gas exchange
Cardiac output (Q)
amount of blood pumped per unit time (usually a min)
Q (L/min) =HR x SV
Stroke volume (SV)
the amount of blood that is ejected or pumped from the LEFT ventricle during systole.
SV = vent. volume - amoutn left
@ rest = 70ml/beat
@ max = 190 ml/breat
during exercise what is the cardiac output distribution compared to at rest?
blood flow at rest is evently set out whereas during exercise, most of the blood flow is to the muscles
Heart heart reserve (HRR)
HRR = Max HR - Resting HR
oxygen uptake:
the amount of oxygen that is consumed by the body due to aerobic metabolism
measured: volume of oxygen that is consumed (vo2) in a given time
incareases in relation to the maount of energy that is required to perform an activity
Vo2max
a measure used to evaluate the maximal volume of o2 that can be supplied to and consumed by the body
the maximal rate at which the body can take up and utilise o2.
absolute = L/min; relative = mL/kg/min
oxygen uptake; incrreased capillarization
can affect the abilty fo the circulatory system to place a RBC close to tissues that are using the oxygen; this increases the ability of those tissues to extract the req’d o2 due to shorter diffusion distance
oxygen uptake: hematocrit
alter the o2 uptake by increasingly or decreasing the amount of o2 that is supplied to working tissues
ability fo the tissues to extract oxygen (a-C o2 difference) directly affects o2 uptake.
Fick Equation
determines the rate at which a person uses oxygen in their body – which is also known as VO2
Vo2= Q x (a-v)02 difference
RBC
erythrocytes
primary fn: transport oxygen from the lungs to the tissues and remove co2 from the body
Hematocrit
the percentage of the blood made up of RBCs
Hemoglobin
- A protein containing iron.
- Each molecule can bond to and transport four oxygen molecules.
- The amount of oxygen that is carried by the blood is dependent upon the partial pressure of oxygen (PO2).
- The difference in the amount of oxygen that is present in the blood as it leaves the lungs and the amount of oxygen that is present in the blood when it returns to the lungs is called the arterial-venous oxygen difference (a-v O2 difference), measured in ml of oxygen per liter of blood (ml O2/L ).
- If the a-v O2 difference increases, it means that the body is using more oxygen.
- The typical a-v O2 difference at rest is about 4 to 5 ml O2/L, while during exercise the a-v O2 difference can increase to 15 ml O2/L.
WHat is EPO?
erythropoeitin
a circulating hormone, is the principal factor that stimulates red blood cell formation.
secreted in response to low oxygen levels (when one goes to altitude) and also in response to exercise, thus increasing the percentage of new red blood cells in the body.
WHere is bv produced?
bone marrow
what is reticulocytes
new rbc
contains more hb than older rbc; carry greater amount of o2
EPO production
high altitude (low o2 level) has an effect on EPO production, which in turn generates a high production of RBC
VO2 max as a predictor of performance
- In elite athletes, VO2 max is a good but not a great predictor of performance.
- VO2 max represents an athlete’s aerobic potential speed at a given VO2 may be more important.
- Same level of aerobic power but one may reach their VO2 max at a running speed of 20 km/hr and the other at 22 km/hr. Running economy (RE) is the energy demand for a given velocity of submaximal running.
- Lactate threshold- more predictive of performance (the speed at lactate threshold vs actual value itself).
lactate threshold
the pt at which white blood lactic acid suddenly rises during incremental exercise
aka anaerobic threshold
practical uses in prediction of performance and as a marker of exercise intensity
Lactate (LA) accumulation
LA accumulation = LA production - LA removal
Other mechanisms for lactate threshold
failure of the mito hydrogen shuttle to keep pace with glycolysis
- excess NADH in sarcoplasm favours converion of pyruvic acid to actic acid
Type of LDH:
- enzyme that converts pyruvic acid to lactic acid
- LDH in fast twitch fibres favours formation of lactic acid
Source of fuel during exercise:
- CHO (blood glucose, muscle glycogen)
- fat (plasma FFA 9from adipose tissue liipolysis); intramuscular triglycerides
- protein (only a small contribution to Total energy production) (may increase to 5-15% late in prolong exercise
- blood lactate (gluconeogenesis via the Cori cycle)
Exercise duration and fuel selection
- during prolong exercise there is a shift from CHO metabolism toward fat metabolism
- increased rate of lipolysis
(breakdown of triglycerides into glycerol and FFA; stimualted by rising blood levels of epinephrine)
interaction of FAT and CHO metabolism durign exercise
fats burn in the flame of CHO
glycogen is depleted during prolong high intensity exercise
- reduced rate of glycolysis and production of pyruvate
- reduced krebs cycle intermediates
- reduced fat oxidation (fats are metabolized by krebs cycle)
respiratory exchange ratio
the ratio between the amount of co2 exhaled and o2 inhaled one breath is the respiratory exchange ratio
RER = VCo2/CO2
Aerobic system changes with training:
Cardiovascular adaptations
cardiac hypertrophy: the "athelete's heart" plasma volume HR Sv Q oxygen extraction (a-delta difference) blood flow nad distribution BP
Plasma volume
during exercise there is a shift of water from the plasma volume to intracellular and Interstitial spaces, thus decreasing overall blood volume
What are the 3 major reasons for decreasing overall volume:
1) Sweating can reduces blood plasma volume.
2) buildup of metabolic by products in the muscle, increases its osmotic gradient, pulls water in.
3) blood pressure increases with exercise forcing water into the interstitial spaces
- exercise can cause blood volume to drop as much as 10%.
- impede performance as it will have a direct result on decreasing the amount of blood returning to the heart and stroke volume..
following endurance training…
Due primarily to two mechanisms which increase plasma volume.
1) exercise induces the release of antidiuretic hormone and aldosterone
act to retain more water and blood volume
2) endurance exercise training can increase the osmotic gradient of blood by increasing plasma proteins, especially albumin.
Aerobic system changes with training:
pulmondary adaptation with training
- maximal exercise (inreaes ventilation)
- submaximal exercise (tidal volumes increases and breathing frequency decreafses)
- training may benefit ventilatory endurance
Aerobic system changes with training:
metabolic adaptation with training
number and size of mito aerobic system enzymes fat and CHO metabolism muscle fibre type and size myoglobin concentration
Aerobic system changes with training:
blood lactate concentration
decreased production
increased clearence
common long term adaptations to endurance training
HR at rest and max decreases SV at rest and max increases Q rest and max increases heart volume increases blood volume increases Other aerobic training adaptations:
Other aerobic training adaptations:
body comps changes (increased lean mass; decreased fat mass)
body heat transfer
performance changes
psychological benefits
