Chronic Cardiopulmonary Adaptations to Exercise

Original Editor - Wanda van Niekerk based on the course by James Laskin

Top Contributors - Wanda van Niekerk and Jess Bell  

This page will focus on chronic adaptations to exercise stimuli - i.e. changes that occur when an individual is regularly training or involved in an appropriate exercise regime for their specific goals and sport.

Adaptations to Training[edit | edit source]

Cardiovascular Changes at Rest[edit | edit source]

Certain changes at rest are evident once an individual starts training regularly (for example, changes from pre-training (week 0) to changes post-training (week 12)). These include:

  • a decrease in resting heart rate because:
    • sympathetic drive decreases[1]
    • atrial contraction rate decreases[1]
    • please note, normal resting heart is 60 to 100 beats per minute[2]
  • increase in stroke volume (SV)[3]


  • decrease in blood pressure:[5]
    • the decrease in systolic blood pressure will be greater than the decrease in diastolic blood pressure[6] - this is related to a decrease in peripheral vascular resistance[7]
  • increase in total blood volume with the maintained concentration of haemoglobin:
    • blood volume = amount of blood circulating through the body
    • increase in plasma volume[8]
    • increase in red blood cells
    • increase in haemoglobin mass[9]
    • oxygen-carrying capacity increases

Cardiovascular Changes with Exercise[edit | edit source]

This compares changes with exercise pre- and post-training programme. For example, a person doing a graded exercise test before commencing a training programme (week 0) and then doing the same test at week 12.

At any given work load, changes include:

  • decrease in heart rate
  • increase in stroke volume up to 50% of maximal workload[10]
    • increase in myocardial contractility[11]
    • increase in ventricular volume[12]
  • cardiac output (Q) stays the same at any given load (pre- versus post-)
    • this is because of the increased stroke volume, and decrease in heart rate
    • cardiac output (Q) = stroke volume (SV) x heart rate (HR)[12]
    • there is an increase of cardiac output only at maximum heart rate (HRmax) due to the concurrent increase in stroke volume (remember maximum heart rate is not trainable, thus at maximum heart rate and with an increase in stroke volume this will result in increased cardiac output at maximum heart rate)[13]
  • there may be a decrease in cardiac output only if there is a change in efficiency or significant weight loss[13]
  • decrease in blood flow per kilogram of working muscle during submaximal exercise
    • trained muscle has increased oxygen (O2) extraction capacity due to improved diffusion capability and muscle respiratory capacity[14]
    • the decrease in muscle blood flow allows for more blood to be distributed to the viscera and skin (for example for thermoregulation)[14]
  • decrease in myocardial oxygen consumption (VO2) because of[15]:
    • myocardial hypertrophy[16]
    • decreased heart rate[15]

Respiratory Adaptations to Training at Rest[edit | edit source]

  • Potential increase in lung volumes:[17]
    • improved pulmonary function
    • no change in tidal volume (TV) [13]
  • Increased diffusion capacity:[17]
    • increased lung volumes
    • increased alveolar-capillary surface area[18]
    • increased blood volume

Respiratory Adaptations to Training with Exercise[edit | edit source]

  • Increased diffusion capacity
  • Increased minute ventilation[17]
  • Increased ventilatory efficiency[19]
  • Decreased pulmonary ventilation at any given workload due to increased diffusion capacity

Metabolic and Morphologic Adaptations to Training at Rest[edit | edit source]

  • Skeletal muscle hypertrophy[20]
  • Increased capillary density[21]
  • Increased number and size of mitochondria[22]
  • Increased myoglobin concentration[23]
  • Increased rate of oxygen (O2) transport

Metabolic and Morphologic Adaptations to Training with Exercise[edit | edit source]

  • Decreased rate of glycogen depletion at any given workload[24]
  • Increased capacity to mobilise and oxidise fat[23]
  • Increased oxidative potential of the mitochondria[23]
  • Increased glycogen storage[23]

Adaptations to Aerobic Training[edit | edit source]

Cardiorespiratory Endurance[edit | edit source]

Aerobic training is the type of repetitive, structured physical activity that requires the body’s metabolic system to use oxygen to produce energy.

  • Cardiorespiratory endurance:
    • ability to sustain prolonged, dynamic exercise
    • improvements achieved through multisystem adaptations (cardiovascular, respiratory, muscle, metabolic)[25]
  • Endurance training:
    • increase in maximal endurance capacity = increase in maximal oxygen consumption (V02 max)
    • increase in submaximal endurance capacity
      • lower heart rate (HR) at the same submaximal exercise intensity
      • this is more related to competitive endurance performance

Cardiovascular[edit | edit source]

  • Oxygen (O2) Transport system and Fick equation:[26]
    • oxygen consumption (VO2) = stroke volume (SV) x heart rate (HR) x arteriovenous oxygen difference (a-v)O2
      • VO2 = SV X HR x (a - v)O2 or VO2 = Q x (a - v)O2
      • Therefore: ↑ VO2max = ↑ max SV x → HR x ↑ max (a -v)O2 difference
      • (a-v)O2 refers to arteriovenous oxygen difference. It is a measure of the amount of oxygen taken up from the blood by the tissues
  • Heart size:
    • with training, heart mass and left ventricular volume increases
      • greater target pulse rate (TPR)[13]
      • cardiac hypertrophy
      • increased stroke volume (SV)
      • increased plasma volume increases left ventricular volume due to an increased preload - this allows for increased end-diastolic volume, which allows for greater stroke volume[14]
  • Stroke volume increases after training:[23]
    • resting, submaximal, and maximal stroke volume[23]
    • increased plasma volume increases stroke volume due to an increased preload on the heart - this increases end-diastolic volume (EDV), which increases cardiac output[14]
    • resting and submaximal heart rate decreases with training, and this increases filling time leading to increased end -diastolic volume[23]
    • increased left ventricular mass with training leads to a greater force of contraction
    • stroke volume adaptations to training decrease with age
  • Resting heart rate:
    • decreases markedly as a result of increased parasympathetic and decreased sympathetic activity in the heart[27]
  • Submaximal heart rate:
    • decreased for the same given absolute intensity[28]
  • Maximal heart rate:
    • no significant changes with training[14]
    • decreases slowly with age
  • Heart rate - stroke volume interactions:
    • heart rate and stroke volume interact to optimise cardiac output
  • Heart rate recovery:[29]
    • faster recovery with training
    • indirect index of cardiorespiratory fitness
  • Cardiac output (Q):
    • training creates little to no change at rest or submaximal exercise[12]
    • maximal cardiac output increases due to an increase in stroke volume
  • Blood flow:
    • increased blood flow to active muscle[12]
  • Increased capillirisation, capillary recruitment:[30]
    • increased capillary:muscle fibre ratio
    • increase in total cross-sectional area for capillary exchange
  • Decreased blood flow to inactive regions[12]
  • Increased total blood volume:[12]
    • prevents any decrease in venous return as a result of more blood in capillaries
  • Blood pressure:[12]
    • decreased blood pressure (BP) at given submaximal intensity
    • increase in systolic BP and decrease in diastolic BP at maximal intensity
  • Blood volume - total volume increases rapidly:[12]
    • increased plasma volume via increased plasma proteins, increased water and sodium (Na+) retention (all in the first 2 weeks of training)
    • increase in red blood cell volume
    • decreased plasma viscosity


References[edit | edit source]

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