Exercise physiology

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Exercise physiology
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Exercise physiology
Recommended literature

1. Wilmore, J. H., Costill, D. L. (1994).
   Physiology of sport and exercise. Champaign, IL
   Human Kinetics.
2. Åstrand, P.-O., Rodahl, K., Dahl. H. A.,
   Strømme, S. B. (2003). Textbook of Work
   Physiology Physiological Bases of Exercise (4th
   ed.). Champaign, IL Human Kinetics.
3. Brooks, G. A., Fahey, T. D., White, T. P.
   (1995). Exercise physiology human bioenergetics
   and its applications (2nd ed.).
4. Mountain View, CA Mayfield Publishing Company.
   Sharkey, B. J. (1990). Physiology of fitness.
   Champaign, IL Human Kinetics.

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Exercise
gt causes the changes in human body A) Acute
response to one bout of exercise e.g. ? heart
rate (HR), ? body temperature (HR)
B) Chronic adaptation to repeated bouts of
exercise - e.g. ? HR at rest and ? HR at
exercise (same intensity)
Muscle activity requires energy. During exercise
are energy demands enhanced. - decrease of ATP,
increase of ADP
Muscle contractile work transforming chemical
energy into kinetic (mechanical) energy
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Energy metabolism
A) Anabolism - creation of reserve
(carbohydrate, fat, proteins)
B) Catabolism release of energy (glycolysis,
lipolysis)
hydrolisis
ATP
ADP P E
phosphorylation
ATP adenosine thriphosphate - common energy
currency ADP adenosine diphosphate P -
phosphate E - energy (e.g. for muscle contraction)
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Energy metabolism

• Energy sources
• 1 Polysaccharides simple sugars
  glucose (glycogen)
• 2 Fats (triglycerides) fatty acids (FFT)
  and glycerol
• 3 Proteins amino acids

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Energy metabolism
Glucose is the only one that can be broken down
anaerobically and aerobically as well.
Anaerobic glycolysis
plasma membrane
blood
cell plasma
G
G
Glycogen (GG)
G 6 - P
2 ATP (G) 3 ATP (GG)
lactic acid
pyruvic acid
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Energy metabolism
Aerobic glycolysis
pyruvic acid (pyruvate)
cell plasma
mitochondrial membrane
mitochondrion
Acetyl CoA
NADH (nicotinamide adenine dinucleotid) and FADH
Citric acid cycle
CO2
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Energy metabolism
oxidative phosphorylation in mytochondrion
(electron transport chain)
NADH O2 3ADP 3ATP NAD H2O
1 NADH3 ATP
FADH O2 2ADP 2ATP FAD H2O
1 FADH2 ATP
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Energy metabolism
From one molecule G GG
Anaerobic glycolysis 2 ATP 3 ATP
Aerobic glycolysis 36 ATP 36 ATP
Total glycolysis 38 ATP 39 ATP
Glycogen reserves are in muscle cells (500 g) and
in liver (100 g). - From 1.500 to 2.500 kcal.
1 calorie (cal) is the amount of energy increases
the temperature of 1 gram H2O from 14.5ºC to
15.5ºC.
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Energy metabolism
Fat - triglyceride FFA (free fat acids)
glycerol in subcutaneous tissue (141 000 kcal).
Adipose tissue
Glucose metabolism
NADH
triglyceride FFA Glycerol
Hormone-sensitive lipase
Beta oxidation
Acetyl CoA
NADH
Citric acid cycle
CO2
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Energy metabolism
anaerobic
aerobic
proteins
Glucose
FFA
and/or
Acetyl CoA
lactic acid
Citric acid cycle
NADH and FADH
Electron transport chain
plasma membrane
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Energy metabolism
Anaerobic metabolism

• only carbohydrate
• increases when lack of O2
• lower amount of ATP, but very fast and huge in
  short time
• production of lactic acid

Anaerobic metabolism

• carbohydrate, fats, proteins
• enough of O2
• higher amount of ATP, but slower

Note proteins are not very important sources of
energy (5-10). Amino acids are preferabely used
as a building matters for muscles hormones, etc.
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Energy metabolism
hydrolisis
ATP
ADP P E
phosphorylation
ATP is only the one immediate source of energy
for muscles work, etc.
Other ways of the creation (phosporylation)
ATP P
ADP CP(creatine phosphate)
ATP AMP
ADP ADP
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Zones of energy supply
Anaerobic free of lactic acid
Anaerobic with lactic acid
Aerobic free of lactic acid
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Total energy expenditure
- s trváním pokles
(?Havlícková et al, 1991)
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• Dominant way of restoration of ATP is oxidative
  phosphorylation

Acute reaction of the body (neurohumoral
controlled) for increase in supply of working
muscles by energy sources and O2

• increase glucose in blood (from liver glycogen)
• activation of FFA (activation of hormone
  sensitive lipase)

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Sources of energy by increasing exercise
intensity
energy expenditure kJ/min
RQ carbohydrates 1
1 g 4,1 kcal
RQ fats 0,7
glycogen
1 g 9,3 kcal
fats
glucose
(Hamar Lipková, 2001)
exercise intensity VO2max
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Sources of energy by increasing exercise
intensity
CO2 - expired
O2 - inspired
RQ respiration quotient ratio between CO2 and
O2
RQ carbohydrates 1 1 l CO2/1 l O2
more O2
RQ fats 0,7 0.7 l CO2/1 l O2
RQ normal (mixed) 0,82
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• Lipids (FFA)
• more energy (1 g 9,3 kcal)
• need more O2 (EE 4,55 kcal)
• use while enough of O2 (at rest, low intensity of
  exercise)

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• Lipids (FFA)
• more energy (1 g 9,3 kcal)
• need more O2 (EE 4,55 kcal)
• use while enough of O2 (at rest, low intensity of
  exercise)

energetic equivalent shows amount of energy
released while applied 1 liter of O2 on
carbohydrate or on FFA
EE
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• Lipids (FFA)
• more energy (1 g 9,3 kcal)
• need more O2 (EE 4,55 kcal)
• use while enough of O2 (at rest, low intensity of
  exercise)

• Carbohydrates
• less energy (1 g 4,1 kcal)
• need less O2 (EE 5,05 kcal)
• use while not enough of O2 (higher intensity, and
  anaerobically as well)
• small amount is always use at rest

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Sources of energy by increasing exercise
intensity
energy expenditure kJ/min
RQ carbohydrates 1
1 g 4,1 kcal
RQ lipids 0,7
glycogen
1 g 9,3 kcal
fats
glucose
(Hamar Lipková, 2001)
exercise intensity VO2max
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• Mechanism of energy release in dependence on
  intensity

VO2max
Anaerobic threshold
NOTE Ideal model
Aerobic threshold
REST
aerobic
anaerobic
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Wasserman scheme of transport O2 a CO2
Ventilation
Muscle work
Transport O2 and CO2
O2
Mito- chon- drion
AIR
lungs
muscles
cardiovascular s.
CO2
(Wasserman, 1999)
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The more O2 is delivered to working muscle, the
higher aerobic production of energy (ATP)
Better endurance performance, smaller production
of lactic acid while the same speed of run,
longer lasting exercise, etc.
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Wasserman scheme of transport O2 a CO2
Ventilation
Muscle work
Transport O2 and CO2
O2
Mito- chon- drion
AIR
lungs
muscles
cardiovascular s.
CO2
(Wasserman, 1999)
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Fick equation
VO2 Q a-vO2

HR
SV
VO2 oxygen consumption ml/min
Q cardiac output ml/min
a-vO2 arteriovenous oxygen difference
SV stroke volume ml
HR heart rate beet/min
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a-vO2 arteriovenous oxygen difference
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DA-V arteriovenous oxygen difference

• difference in the oxygen content of arterial and
  mixed venous blood
• the value tells about the amount of oxygen used
  by working muscles
• depends on the muscle ability to absorb and use
  the O2 from blood (perfusion, amount of
  capillary, mitochondrion, number of working
  muscles, etc.)

- at rest 50 ml O2 from 1 L of blood
- during exercise 150-170 ml O2 1 L of blood
(100 ml krve is saturated by 20 ml O2)
(1 L of blood is saturated by 200 ml O2)
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1 L of blood is saturated by 200 ml O2

• To ensure during exercise
• ?BF (breathing frequency, rate)
• - from 12-16 breath/min up 60 (70 and more)
• ?TV (tidal volume)
• from 0.5 L up 3 L

Minute ventilation (VE) BF TV - at rest 6
L/min 12 0.5 - during maximal exercise 180
L/min 60 3
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(No Transcript)
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.
VO2 Q DA-V
Q HR SV
rest SEDENTARY
4,9 L 70 beet/min 70 ml
rest TRAINED
4,9 L 40 beet/min 120 ml
In work increase of HR and SV - ? Q

• SV increases till HR 110 120 beet/min
• (from 180 beet/min decreases)
• - HRmax 220 - age

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.
VO2 Q DA-V
Q HR TV
rest SEDENTARY
4,9 L 70 beet/min 70 ml
rest TRAINED
4,9 L 40 beet/min 120 ml
rest
VO2 4,9 L of blood 50 ml O2
VO2 245 ml/min
human (70kg) 245 70 3,5 ml O2/kg/min (1MET)
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.
VO2 Q DA-V
Q SF SV
Max. exercise SEDENTARY
20 L 200 beet/min 120 ml
Max. exercise TRAINED
35 L 200 beet/min 175 ml
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.
VO2 Q DA-V
Max. exercise
SEDENTARY
VO2max 20 L of blood 157 ml O2
VO2 max 3140 ml/min
70 kg human 3140 70 45 ml O2/kg/min (13 METs)
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.
VO2 Q DA-V
Max. exercise
TRAINED
VO2max 35 L of blood 170 ml O2
VO2 max 5950 ml/min
70 kg human 5950 70 85 ml O2/kg/min (25 METs)
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Definition and explanation of VO2max

• VO2max
• is maximum volume of oxygen that by the body can
  consume during intense (maximum), whole body
  exercise.
• - expressed
• - in L/min
• - in ml/kg/min
• - METs

1 MET - resting O2 consumption (3.5 ml/kg/min)
10 METs 35 ml/kg/min
20 METs 70 ml/kg/min
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Importance of VO2max
Higher intensity of exercise
Higher energy demands (ATP)
Increase in oxygen consumption
Lower VO2max less energy worse achievement
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Importance of VO2max
During endurance activity is being ATP
resynthesized mainly aerobically from lipids and
carbohydrates.
The more is O2 supplied to working muscles, the
more higher is an amount of aerobically produced
energy. It means higher speed of running, latest
manifestation of fatigue, etc.
It shows the capacity for aerobic energy transfer.
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Average values of VO2max
Average (20/30 years) not trained - female 35
ml/kg/min - male 45 ml/kg/min Trained to 85
ml/kg/min (cross-country skiing)
Decreases with age. Lower in female.
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Average values of VO2max
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Limitation factors of VO2max
Ventilation
Muscle work
Transport O2 and CO2
O2
AIR
lungs
muscles
cardiovascular s.
CO2
(Wasserman, 1999)
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Limitation factors of VO2max

• 1) Lungs no limitation factor

2) Muscles is limitation factor
3) Cardiovascular system dominant limitation
factor
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Wasserman scheme of transport O2 a CO2
Ventilation
Muscle work
Transport O2 and CO2
O2
Mito- chon- drion
AIR
lungs
muscles
cardiovascular s.
CO2
(Wasserman, 1999)
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VO2max Qmax DA-Vmax

• On increase of VO2max participate
• Increase of DA-Vmax shares on increase about
  20
• Increase of Qmax shares aboout 70 - 85

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Influence of the gender, health condition, age
Heredity the increase of VO2max by training
only to max. 25
Gender in female lower muscle mass, lover
hemoglobin
Age decrease of active body mass, activity of
enzymes
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Sources of energy by increasing exercise
intensity
energy expenditure kJ/min
RQ carbohydrates 1
1 g 4,1 kcal
RQ lipids 0,7
glycogen
1 g 9,3 kcal
fats
glucose
(Hamar Lipková, 2001)
exercise intensity VO2max
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VO2max ml/kg/min
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AT 50-60 VO2max
3,5
exercise intensity (speed, load, etc.)
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• AT (aerobic threshold)
• - exercise intensity, when exclusive aerobic
  covering ends.
• exercise intensity, from which anaerobic covering
  starts and lactate is being produce
• level of lactate 2 mmol/L of blood

50
VO2max ml/kg/min
plateau
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AnT 70-90 VO2max
AT 50-60 VO2max
3,5
exercise intensity (speed, load, etc.)
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• AnT (anaerobic threshold)
• - exercise intensity, when anaerobic covering
  exceed aerobic.
• - exercise intensity, when dynamic balance
  between production and breakdown of lactate is
  disturbed
• level of lactate 4 mmol/L of blood and is
  increasing (onset of blood lactate accumulation).
• at about approximately 8 mmol/L o blood is
  impossible to continue in exercise (trained even
  30 mmol/L of blood)

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• AnT (anaerobic threshold)
• - can be estimate from VO2max
• AnT VO2max/3,5 60
• AnT 35/3,5 60
• AnT 70 VO2max

60 of VO2max - AT
1 MET
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VO2max ml/kg/min
45
AnT 70-90 VO2max
AT 50-60 VO2max
3,5
exercise intensity (speed, load, etc.)
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lactate
energy sources
fiber type
VO2max ml/kg/min
onset of lactate accumulation ? pH
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fat lt sugar
AnT 70-90 VO2max
I., II. a, II. b
4 mmol/L
L is oxidized (heart ,not working muscles)
I., II. a
fat sugar
2 mmol/L
AT 50-60 VO2max
I.
fat gt sugar
? 1,1 mmol/L
3,5
exercise intensity (speed, load, etc.)
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(Hamar Lipková, 2001)
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• Exercise intensity during endurance activity (gt30
  minutes) can not be above AnT.
• Before start of exercise
• - increase in O2 consumption (emotions,
  reflexions)
• 2) Initial phase of exercise (till 5 minutes)
• - rapid increase of the oxygen consumption
• Steady state
• - balance between the energy required by working
  muscles and the rate of ATP produced by aerobic
  metabolism
• - O2 is almost constant
• - lactate level is constant
• - HR is in the range 4 beats (right steady
  state)

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VO2max ml/kg/min
O2 deficit
AnT
3.5
Time min
0
5
30
before start
initial phase
steady state
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• Oxygen deficit
• Insufficient supply of working muscles with O2,
  at the beginning of exercise (slower ? SF and SV,
  BF and TV).
• disbalance between O2 demands and supply leads to
  use of anaerobic metabolism production of
  LACTATE ( ? H metabolic acidosis death
  point).
• when O2 demands ensured second breath
• after termination of exercise the increased O2
  consumption persists oxygen debt

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VO2max ml/kg/min
O2 deficit
O2 debt
AnT
3.5
Time min
0
5
30
before start
initial phase
steady state
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• Oxygen debt
• synthesis of ATP and CP
• resynthesis of lactate (back to glycogen in the
  liver, and oxidation by muscles and myocardium)
• - acceleration of release of lactate from
  muscles and better blood perfusion of muscles
  resynthesising lactate, is possible by low
  intensive exercise (till 50 VO2max
  below AT)
• recovery of myoglobin, hemoglobin, hormone,
  etc.
• the major part (till 30 min), mild oxygen debt
  can persist 12-24 hours.

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VO2max ml/kg/min
false steady state - above AnT
major O2 debt
AnT
3.5
Time min
0
5
25
before start
initial phase
steady state
62
VO2max ml/kg/min
smaller O2 debt
AnT
AP
3.5
Time min
0
30
2
before start
initial phase
steady state
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oxygen consumption (L/min)
trained
- steady state is reached earlier
sedentary
- steady state is reached latter
rest
exercise
time (min)
(Hamar Lipková, 2001)
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Practical importance of VO2max
VO2max 70ml/kg/min
AnP VO2max/3,5 60
80
VO2max 35 ml/kg/min
70
male A
female
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Practical importance of VO2max
VO2max 70ml/kg/min
VO2max 70 ml/kg/min
90
80
male A
male B
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Critical parameter of aerobic abilities is not
VO2max, but AnT. However VO2max is conditional
parameter of AnT.