VO2 MAX &
TRAINING ADAPTATIONS
Oxygen Consumption (VO2)
• The amount of o2 taken up and consumed
by the body for metabolic processes.
• Equal to amount of inspired air minus
amount of expired air
• VO2 is proportional to workload
• Measured by a metabolic cart in a lab
environment
..cont.
• The maximal rate of oxygen consumption
would occur at max HR, SV.
• VO2 max is the maximal amount of O2
that can be taken in and used for the
metabolic production of ATP during
exercise
Limiting factors to VO2
• The Respiratory System: Inadequate ventilation and
oxygen diffusion limitations
• The cardiovascular system: Inadequate blood flow;
inadequate oxygen-carrying capacity (Q likely the
biggest limiting factor)
• Energy systems: Lack of mitochondria
• Heredity: Accounts for between 25% and 50% of the
variance in VO2 Max values.
• Age: Related decreases in VO2 Max might partly
result from an age-related decrease in activity levels.
• Gender: Plays a small role (10%) in the VO2 Max
values of male and female endurance athletes.
Oxygen Deficit and EPOC
Con’t
• Oxygen deficit: Difference between the
O2 required to perform a task and the
O2 consumed before reaching steady
state (sub-maximal)
• Trained individuals reach this state
earlier than non-trained individuals.
EPOC
• Excess Post-exercise Oxygen Consumption:
The extra oxygen required to replenish oxygen to
the various systems that were taxed during the
exercise.
• Eg: Refilling phosphocreatine reserves,
replenishing O2 in blood and tissues, lowering
breathing rate, lowering body temp. and
increasing blood lactate removal.
• Active recovery can aid in the removal of blood
lactate.
Physiological Adaptations Due
to Endurance Training
Cardiovascular Adaptations
From Aerobic Training
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Increased cardiorespiratory endurance
Increased muscular endurance
Decreased VO2 at rest and submaximal exercise
Increased VO2 Max
Increased heart weight, volume, and chamber size
– Increased left ventricle wall thickness “athletes heart”
– Increased left ventricle EDV
– Increased blood plasma
• Increased Stroke Volume
Cardiovascular Adaptations
From Aerobic Training
• Decreased Resting Heart Rate
• Decreased submaximal heart rate
• Decreased maximum heart rate of elite athletes
– if your heart rate is too fast the period of ventricular
filling is reduced and your stroke volume might be
compromised.
– the heart expends less energy by contracting less
often but more forcibly than it would by contracting
more often.
• Decreased Heart Rate Recovery
Cardiovascular Adaptations
From Aerobic Training
• Maintained cardiac output at rest and submaximal
exercise
• Increased cardiac output during maximal exercise
• Increased blood flow to the muscles
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increased capillarization of trained muscles
greater opening of existing capillaries in trained muscles
more effective blood redistribution
increased blood volume
decreased blood viscosity & increased oxygen delivery
• Decreased resting blood pressure
– from increased blood flow
Cardiovascular Adaptations
From Aerobic Training
• Increased blood volume (blood
plasma) and is greater with more
intense levels of training
– increased plasma proteins which help
retain blood fluid
– increased red blood cell volume
– decreased blood viscosity
Respiratory Adaptations
From Aerobic Training
• Respiratory system functioning usually does not
limit performance because ventilation can be
increased to a greater extent than cardiovascular
function.
• Slight increase in Total lung Capacity
• Slight decrease in Residual Lung Volume
• Increased Tidal Volume at maximal exercise levels
• Decreased respiratory rate and pulmonary
ventilation at rest and at submaximal exercise
– (RR) decreases because of greater pulmonary
efficiency
• Increased respiratory rate and pulmonary
ventilation at maximal exercise levels
– from increased tidal volume
Respiratory Adaptations
From Aerobic Training
• Unchanged pulmonary
diffusion at rest and
submaximal exercise.
• Increased pulmonary
diffusion during maximal
exercise.
– from increased circulation and
increased ventilation
– from more alveoli involved
during maximal exercise
• Increased A-VO2 difference
especially at maximal
exercise.
Metabolic Adaptations From
Aerobic Training
• Lactate threshold occurs at a higher percentage of VO2
Max.
– from a greater ability to clear lactate from the muscles
– from an increase in skeletal muscle enzymes
• Decreased Respiratory Exchange Ratio (ratio of carbon
dioxide released to oxygen consumed)
– from a higher utilization of fatty acids instead of carbo’s
– however, the RER increases from the ability to perform at
maximum levels of exercise for longer periods of time
because of high lactate tolerance.
• Increased resting metabolic rate
• Decreased VO2 during submaximal exercise
– from a metabolic efficiency and mechanical efficiency
Metabolic Adaptations From
Aerobic Training
• Large increases in VO2 Max
– in mature athletes, the highest attainable VO2 Max is
reached within 8 to 18 months of heavy endurance
training.
– VO2 Max is influenced by “training” in early childhood.
• from increased size and number of mitochondria
• from increased blood volume, cardiac output & O2
diffusion
• from increased capillary density
Physiological Adaptations Due
to Endurance Training