Physiology

Physiology

1. Aerobic adaptations to training

   • Factors determining effectiveness
     • Training volume
     • Training Intensity
   • Endurance
     • Cardiorespiratory endurance
     • Muscular enduarance
   • Testing for health and performance
     • Heart
       • <3 rate
       • Echocardiogram
       • ECG
       • Exercise testing
     • Circulatory system
       • Blood pressure
       • Ultrasound
       • Lipid profile
     • Respiratory system
       • Spirometry
       • O2 saturation
       • Exercise performance
       • Measuring forced expiratory volume
     • Health
       • Anxiety
       • Depression
       • Perceived quality of life
     • Performance
       • Memory
       • Dual task
       • Executive fx
   • Lab tests
     • Max tests
       • Vo2 max testing
         • Highest rate of 02 consumption possible during exercise
         • Can be increased by 15-20% within 20 weeks
         • Expressed as absolute (in L) or relative (ml/kg/min)
         • Time to fatigue at V02 max
           • 100% = 5min
           • 90% = 15 min
           • 80% = 45 min
           • 70% = 2.5 hours
           • 60% = >3hours
         • V02 = Q (SV * HR) * A-V (02 diff)
       • Astramd treadmill
       • Windgate
       • Bleep / YOYO
     • Sub-max
       • Astrand-rhyming cycle
       • Modified Bruce protocols
       • PWC 75% and PWC170
   • Cardiovascular adaptations
     • <3 size
       • Especially LV wall (Hypertrophy)
     • <3 rate
       • Resting HR
         • With training RHR can decrease with training - possible to detrain
         • Remodelling of SA node - Calcium, Sodium, Potassium
         • Q = SV * HR
       • Sub max HR
         • Lower HR at exercise intensity after training
         • Q = SV * HR - therefore if SV has increased - there is a more noticeable at higher intensities
       • MAX HR
         • 220 - Age
         • Elite athletes < sedentary population
         • Declines with age
         • Faster HR = less filling time = lower SV
           • Most efficient combo is a lower HR with greater SV to provide sufficient o2
       • HR recovery
         • Improved training status = more efficient recovery
         • Factors to influence recovery
           • Temp
           • Mental state
           • Distractions post-exercise
           • Altitude
     • Stroke volume and Cardiac output
       • Increased SV
         • SV = EDV - ESV
       • Increased End diastolic volume
         • Due to increased fitness and a slower HR, The fuller that ventricle is the larger the contraction is
       • Decreased End systolic volume
         • Stronger contraction = less remaining blood
       • RBC volume
         • Correlated with Vo2 max
         • Ensures body has ability to deliver 02 to exercising muscle
         • Haematocrit (% of blood volume that is RBC) decreases
           • Greater increase in plasma than RBC
         • Athletes can seem anaemic
       • Increased Blood flow
         • Increased capillirisation
           • Angiogenesis
             • Formation of new capillaries in trained muscles
             • Can increase by up to 15%
               • Expressed as capillary to fibre ration (normally 1.1 untrained and 1.5 in trained)&nbsp;
         • Better recruitment of existing capillaries
           • Not all capillaries are open at one time
           • More capillaries open in trained muscles
           • Increase in overall surface area for oxygen diffusion
         • Greater blood volume
           • Total bodily blood increases
           • Blood is made of plasma + formed elements
         • More effective distribution
           • Blood is shunted away from areas that dont need it during exercise
           • More blood directed to oxidative muscle fibres
             • Away from Glycotic
         • increase in plasma after training
           • Because of an increase in plasma proteins and a change in oncotic pressure
             • Causes more fluid to being reabsorbed into blood vessels&nbsp;
           • Exercise causes release of antidiuretic hormone and aldosterone
             • Exercise causes release of antidiuretic hormone and aldosterone = reabsorption of H20 and NA in kidneys
         • Blood pressure adaptations
           • Larger influence on those with higher BP after endurance exercise
           • @ max exercise - SBP slight increase, DBP little change
           • MAP reduced @ sub max intensity
   • HR max
     • Elite athletes have a lower HR max
     • declines with age
     • Faster HR = ;ess filling time = lower SV
     • Improved training status = more efficient recovery period
   • Respiratory adaptations
     • Pulmonary Ventilation
       • Resting PV Unchanged after training
       • Increases by 30% at sub max
       • Maximum pulmonary ventilation
         • Highly trained - 180L/min
         • Sedentary - 100-120L/min
         • Trained - 130 - 150 L/min
         • Large highly trained - 200 L/min
       • Variables making up pulmonary ventilation
         • Increased tidal volume
         • Increased respiratory frequency
           • Ventilation not normally a limiting factor
             • 02sat < 96% = exercise induced arterial hypoxemia
     • Pulmonary diffusion
       • Gas exchange (GE) unaltered at rest and during sub-max exercise
         • GE increases at max intensity
       • As BF increases so does total perfusion
       • As ventialation increases - more pulmonary ventilation occurs
       • Number of alveoli increases
     • A-vO2 difference
       • With training A-v02 diff increases
       • Lower venous O2 content reflects greater 02 extraction
   • Muscular adaptations
     • Muscle fibre types
       • Type l
         • Slow twitch - oxidative Increases in X sectional area of 25% have been observed
         • INCREASE from 43% pre to 47% post training
       • Type lla
         • Faster twitch muscle fibres Oxidative capacity&nbsp;
         • No change
       • Type llx
         • Low oxidative capacity&nbsp;
         • Decrease from 20% pre to 15% post training
     • Myoglobin content
       • Myoglobin is a protein that shuttles 02 muscle cell membrane to mitochondria
       • 2 types: Deoxymyoglobin and Oxymyoglobin
       • More present in type l muscle fibres
       • Lack of myoglobin in type ll muscle fibres reduces oxidative capacity
       • Endurance training can increase muscle myoglobin content by 75%
       • If Found in blood stream = sign of muscle injury
     • Mitochondria fx
       • WHY NB
         • Oxidative energy production
         • mitochondrial density
           • Increase in number and size of mitochondria after endurance training
         • Increases of 15% in number and 35% in size after 27 weeks of exercise observed
         • Biogenesis and mitophagy
         • Exercise slows down the degeneration of mitochondria
         • Turnover of mitochondria dependent on a regulator protein: peroxisome proliferator-activated receptor coactivator 1α
           • Peroxisome proliferator-activated receptor coactivator 1α
             • controls replacement of weakened mitochondria
         • Exercise training (endurance and resistance) improve the expression of this protein.
     • Oxidative enzymes
       • WHY NB?
         • Responsible for oxidative breakdown of fuels and production of ATP
         • Aerobic training increases activity of these enzymes
         • Increases in enzyme activity increase beyond VO2max increases
         • Training improvements may be limited by circulatory limitations more than muscle oxidative potential
       • activity for 20 min / day increases succinate dehydrogrenase activity by more than 25%
         • 60 - 90 ,im of training / day = 2 / 3 X increase in enzyme activity
       • Glycogen sparing is also improved by exercise – slower rate of glycogen utilisation and more reliance on fat at any intensity.

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