ENERGETIC METABOLISM
= summary of all chemical (and physical) processes included in:
1. Production of energy from internal and external sources
2. Synthesis and degradation of structural and functional tissue
components
3. Excretion of waste products and toxins from body
Metabolic speed: amount of energy released per unit of time
Calorie (cal) = amount of thermal energy, necessary for warming up 1g of water
for 1°C, from 15°C to 16°C
METABOLISM
Complex, slow process = CATABOLISM = release of
energy in small quantities
Energy storage in the energy-rich phosphate compounds
and in the form of proteins, fats and complex
carbohydrates (synthesized from simpler molecules).
Creation of these compounds = ANABOLISM (energy
is consumed).
Calorie (cal, small calorie, gram calorie)
Kilocalorie = kcal = 1000 cal = 4,18 kJ
Joul = J = 0,239 cal
Kilojoul = kJ = 1000 J
SACCHARIDES
LIPIDS
PROTEINS
ENERGY
INPUT =
ENERGY
CONSUMPTION
MECHANIC
WORK
SYNTHESIS
MEMBRANE
TRANSPORT
PRODUCTION AND
TRANSMISSION
OF SIGNALS
HEAT
PRODUCTION
DETOXICATION
DEGRADATION
Muscle contraction
Movement of cells,
organelles, flagella
Energetic stores
production
Tissue growth
Essential molecules
production
Minerals
Organic ions
AA
Electrical
Chemical
Mechanical
Body temperature
control
Ineffective chemical
reactions
Urine production
Conjugation
Oxidation
Reduction
Kittnar, O. et al.
Lékařská fyziologie.
1st Ed. Grada
Publishing 2011
regulation of food intake
I. thermodynamic law:
At steady state, input of energy equals to its expenditure
Input stores
Expenditure of energy = external work + energy stores + heat
Intermediate stages: various chemical, mechanical and thermal reactions
ENERGY INTAKE (INPUT)
Saccharides, lipids, proteins
Burning releases: 4.1kcal/g, 9.3kcal/g, 5.3kcal/g (4.1 in body) 1kcal=4184J
Conversion of proteins and saccharides to lipids – effective storage of the energy
Conversion of proteins to saccharides – need of „fast“ energy
BUT: there is no significant conversion of lipids to saccharides
Kittnar, O. et al.
Lékařská fyziologie.
1st Ed. Grada
Publishing 2011
Glu
Liver
tissue
Anabolic
processes
Glycogen
Fats
Peripheral
tissues
Catabolic
processes
ATP
Waste
products –
H2O and CO2
Triacylglycerols
Lipoprotein
lipase
MAG
FA
Liver
tissue
Gluconeogenesis
Adipose
tissue
Catabolic
processes
ATP
Waste
products –
H2O and CO2
Anabolic
processes
Triacylglycerols
Amino acids
Liver
tissue
Anabolic
processes
Proteins
Peripheral
tissues
Catabolic
processes
ATP
Waste
products –
H2O and CO2
ENERGY OUTPUT
1. At rest: basal metabolism; 8 000 kJ / day; 200-250 ml O2/min; directly
depends on body mass and surface; decreases with age; increases with
ambient temperature; decreases by 10-15% during sleep; genetically
determined 75%BM
2. After meal: slight increase in energetic output – specific dynamic effect –
e.g. for glycogen formation 7%BM
3. Facultative thermogenesis: non-shivering
4. In sitting people: spontaneous physical activity 18%BM
5. During exercising: energetically most demanding; individual; changes
according to season
Kittnar, O. et al. Lékařská fyziologie. 1st Ed. Grada Publishing 2011
ENERGY PRODUCTION
O2 + ADP
GLYCOLYSIS b-OXIDATION
Hexose
C6H6O6
(2)pyruvate (2)acetyl-CoA(n/2)
2ATP
4ATP
4H
4H
Each acetyl-CoA
Citrate
cycle
8H
Fatty acid
CnH2nO2
ATP
2(n-2)H
2(n-2)H
Oxidative phosphorylation
ATPH2O
2 CO2
GTP
proteins
AMK
•Energy stores: ATP, creatinphosphate, GTP, CTP (cytosin), UTP (uridin), ITP (inosin)
•Macroergic bond – 12kcal/mol
•Efficiency is not 100% - 18kcal of substrate to 1 bond in ATP
•Daily: 63 kg of ATP (128 mol)
•Glycolysis: only short-lasting source of energy (2 pyruvates – only approx. 8% of glucose
energy); supply of glucose is limited, lactate
ATP
• Production of ATP mainly in mitochondria (up to 95%)
• Central role of acetyl-CoA and Krebs cycle
• Highly reactive hydrogen atoms = used for the conversion
of ADP to ATP
• Chemiosmotic mechanism of ATP production
Guyton and Hall
Textbook of Medical
Physiology. 12th
Ed. Elsevier 2006
Use of ATP in cells
– Membrane transport (Na+, K+, Ca2+,Mg2+, phosphate, Cl-, urate,
hydrogen ions, specific types of transport – Glu, AAs, acetoacetate) –
80 % in some types of cells
– Synthesis of chemical compounds (phospholipids, cholesterol, purine
and pyrimidine bases, proteins, urea – detoxifying function-ammonia)
• In some types of cells up to 75 %
• 500 – 5000 cal for creation of 1 M of protein (peptide bonds)
• Synthesis of Glu from lactate and FA from acetyl-CoA
– Mechanic work
• Role of myosin and conversion of ATP to ADP
– Secretion of glands
– Neurotransmission
Regulation of ATP production
• Oxidative phosphorylation
• Flavoprotein-cytochrome system
– Transport of protons across the inner mitochondrial membrane, creation
of electrochemical potential and transport of protons back into the
matrix – role of ATP synthase
– Regulation:
• Consumption of ATP in tissues (OP increases with increasing ATP
consumption)
• Rate of uptake of fats, lactate, and glucose into mitochondria
• Availability of oxygen – mitochondria under basal condition
consume 90% of oxygen, 80% is connected with the synthesis of
ATP
• Oxidation at the substrate level
– Production of ATP at processes that release large amounts
of energy
Silverthorn, D. U. Human
Physiology – an Integrated
Approach. 6th. edition.
Pearson Education, Inc.
2012.
Silverthorn, D. U. Human
Physiology – an Integrated
Approach. 6th. edition.
Pearson Education, Inc.
2012.
Silverthorn, D. U. Human
Physiology – an Integrated
Approach. 6th. edition.
Pearson Education, Inc.
2012.
Silverthorn, D. U. Human Physiology – an Integrated Approach. 6th.
edition. Pearson Education, Inc. 2012.
ATP synthase
• Thylakoid
membrane and
the inner
mitochondrial
membrane
• F0 and F1
(matrix)
„segments“
• F1 – 5 subunits
• F0 – 10
subunits
Phosphocreatine
• The most abundant
macroergic (substance)
compound
• 3 – 8x larger amounts
compared to ATP
• 8500 cal/M and 13000
cal/M at 37°C and low
concentrations of reactants
(ATP 12000)
• dynamic process of energy
transfer and mutual
conversion of ADPphosphocreatine
/ creatine-
ATP
• „ATP-phosphocreatine
system = maintenance of
ATP amounts
STORAGE AND TRANSPORT OF ENERGY
•Both input and otput of energy are irregular – necessity of storage
•75% of stores: triglycerides (9kcal/g) in adipose tissue (10-30% of body mass),
lasts up to 2 months ; source – dietary FA and esterification with aglycerolphosphate
or synthesis from acetylCoA (from glycolysis) – saccharides are
converted to more effective store of energy = lipids
•25% of stores: proteins (4kcal/g); conversion to saccharides (gluconeogenesis
during stress); adverse effects on organism
•Less than 1% of stores: saccharides (4kcal/g) as glycogen; important for CNS!!!
and short-term enormous exercise; ¼ of glycogen stores in liver (75-100g), rest in
muscles (300-400g); liver glycogen – glycogenolysis – release of glucose; muscle
glycogen – used only in muscles (no glukoso-6-phosphatase)
•Gluconeogenesis: from pyruvate, lactate and glycerol and AA (except of
leucin);NO from acetyl-CoA
•Storage and transport of energy requires input of other energy: 3% from original
energy – lipids (triglycerides to adipose tissue), 7% - glucose (glycogen), 23% conversion
of saccharides to lipids, 23% - conversion of AA to proteins or glucose
(glycogen).
GLUCOSE AND FA
• Alternative
• Reciprocal relationships between utilisation, synthesis and storage
• ABUNDANCE OF GLUCOSE – acceleration of glycolysis – more pyruvate, more
citrate – citrate activates 1.step in synthesis of FA (acetyl CoA – malonyl CoA)
• Accelerated glycolysis – more glycerol phosphate; increased synthesis of FA and
increased availability of glycerol phosphate = stimulation of synthesis of
triglycerides and reduction of b-oxidation
• THUS: increased utilisation of saccharides shifts lipid metabolism from oxidation
to storage
• OVERSUPPLY WITH FA – acceleration of b-oxidace; its intermediates slow down
glycolysis and accelerate gluconeogenesis and glycogenogenesis
• THUS: increased utilisation of FA shifts saccharide metabolism from oxidation to
storage
• Humoural regulation
TRANSPORT OF ENERGY BETWEEN ORGANS
Adipose tissue Muscles
Liver
Triglycerides
Free FA
FA
CO2
Muscle
work
Lactate
Lactate
Pyruvate
Glucose
Glucose
ATP
H+
Muscle – source of energy and
metabolism
• = conversion of energy into mechanic work
• Phosphocreatine – hydrolysis to creatine and phosphate
• At rest, some ATP in the mitochondria transfers its phosphate to creatine = phosphorylcreatine store is built up
• During exercise, the phosphorylcreatine is hydrolyzed at the junction between the myosin heads and actin,
forming ATP from ADP and thus permitting contraction to continue
• At rest and during light exercise, muscles utilize lipids in the form of free fatty acids as their energy source
• As the intensity of exercise increases, lipids alone cannot supply energy fast enough and so use of carbohydrate
becomes the predominant component in the muscle fuel mixture
• During exercise, much of the energy for phosphorylcreatine and ATP resynthesis comes from the breakdown of
glucose to CO2 and H2O
• Glucose in the bloodstream enters cells, where it is degraded through a series of chemical reactions to pyruvate
• Another source of intracellular glucose, and consequently of pyruvate, is glycogen
• When adequate O2 is present, pyruvate enters the citric acid cycle and is metabolized—through this cycle and
the so-called respiratory enzyme pathway—to CO2 and H2O = AEROBIC GLYCOLYSIS, large quantities of
ATP from ADP
• If O2 supplies are insufficient, the pyruvate formed from glucose does not enter the tricarboxylic acid cycle but
is reduced to lactate = ANAEROBIC GLYCOLYSIS - it does not require the presence of O2
• After a period of exertion is over, extra O2 is consumed to remove the excess lactate, replenish the ATP and
phosphorylcreatine stores, and replace the small amounts of O2 that were released by myoglobin - oxygen debt
• When muscle fibers are completely depleted of ATP and phosphorylcreatine, they develop a state of rigidity
called rigor
Heat production in muscle
• Thermodynamically, the energy supplied to a muscle must equal its energy output
• The overall mechanical efficiency of skeletal muscle (work done/total energy
expenditure) ranges up to 50% while lifting a weight during isotonic contraction
and is essentially 0% during isometric contraction
• Considerable heat production
• Resting heat, the heat given off at rest, is the external manifestation of basal
metabolic processes
• The heat produced in excess of resting heat during contraction is called the initial
heat. This is made up of activation heat, the heat that muscle produces whenever it
is contracting, and shortening heat, which is proportionate in amount to the
distance the muscle shortens
• Recovery heat is the heat liberated by the metabolic processes that restore the
muscle to its precontraction state.
• If a muscle that has contracted isotonically is restored to its previous length, extra
heat in addition to recovery heat is produced = relaxation heat
Hormones and metabolism
Kittnar, O. et al.
Lékařská fyziologie.
1st Ed. Grada
Publishing 2011
Hormones and metabolism of
saccharides
• Insulin, IGF-I / II, glucagon, somatostatin, epinephrine,
thyroid hormones, glucocorticoids, growth hormone
• Exercise
– Entry of glucose into skeletal muscle is increased during exercise in the
absence of insulin by causing an insulin-independent increase in the
number of GLUT 4 transporters in muscle cell membranes
– It persists for several hours after exercise, and regular exercise training
can also produce prolonged increases in insulin sensitivity
– Exercise can precipitate hypoglycemia in diabetics
– Patients with diabetes should take in extra calories or reduce their
insulin dosage when they exercise
• Catecholamines
– Activation occurs via β-adrenergic receptors, which increase intracellular cAMP, and αadrenergic
receptors, which increase intracellular Ca2+.
– Hepatic glucose output is increased, producing hyperglycemia
– In muscle, the phosphorylase is also activated via cAMP and presumably via Ca2+, but
the glucose 6-phosphate formed can be catabolized only to pyruvate because of the
absence of glucose 6-phosphatase
– Large amounts of pyruvate are converted to lactate, which diffuses from the muscle into
the circulation
– The lactate is oxidized in the liver to pyruvate and converted to glycogen
– Lactate oxidation may be responsible for the calorigenic effect of epinephrine
• Thyroid hormones
– The principal diabetogenic effect of thyroid hormones is to increase absorption of
glucose from the intestine, but the hormones also cause (probably by potentiating the
effects of catecholamines) some degree of hepatic glycogen depletion
– Thyroid hormones may also accelerate the degradation of insulin
– Calorigenic effect = increase of oxygen consumption almost in all tissues
• Adrenal glucocorticoids
– Increased catabolism of proteins in tissues = increased amount of free AAs in blood plasma
– Increased trapping of Aas in liver
– Increased deamination and transamination of Aas
– Increased conversion of oxalacetate to phosphopyruvate
– Increased activity of liver fructose diphosphatase
– Increased activity of liver glucose-6 phosphatase
– Reduced utilization of glucose in peripheral tissues
– Increased amounts of lactate and pyruvate in blood
– Reduced lipogenesis in liver
– Increased plasma levels of FFA
– Increased production of keto compounds
– Increased production of active glycogen synthase
• Growth hormone
– Growth hormone mobilizes FFA from adipose tissue, thus favoring ketogenesis
– It decreases glucose uptake into some tissues (“anti-insulin action”), increases hepatic
glucose output, and may decrease tissue binding of insulin
• Saccharides (glucose)
C6H12O6 + 6O2 = 6CO2 + 6H20
RQ = 6/6 = 1,00
• Fats (tripalmitin)
2 C51H96O6 + 145 O2 = 102 CO2 + 98 H2O
RQ = 102/145 = 0,703 (0,70)
• At hyperventilation RQ increases (more CO2).
• At intense exercise RQ 2.00 (more CO2 + lactate is converted to CO2)
• After the exercise RQ decreases down to 0.50
• At metabolic acidosis RQ increases.
• At metabolic alkalosis RQ decreases.
RESPIRATORY QUOTIENT
RQ = VCO2 : VO2
Saccharides: RQ = 1
Lipids: RQ = 0,7
Proteins: RQ = 0,8(per unit of time, at steady state; related to 1 L
of oxygen)
R – ratio of respiratory exchange (no steady state!)
• Metabolic rate / speed of metabolism
1. Physical work (during recovery - compensation of oxygen debt).
2. Specific dynamic action (thermic effect, dietary induced thermogenesis) of food
= amount of energy expenditure above the resting metabolic rate due to the cost of
processing food for use and storage
= energy required for digestion, absorption, and disposal of ingested nutrients
• A) The amount of protein that provides 100 kcal,
increases metabolic rate for 30 kcal.
• B) The amount of saccharide that provides 100 kcal,
increases metabolic rate for 6 kcal.
• C) The amount of fats that provides 100 kcal,
increases metabolic rate for 4 kcal.
• The amount of energy of the nutrients is reduced by the specified amount of energy
that was used to their assimilation.
– Proteins have the highest value of SDA ()
– instead of 100 kcal organism gets only 70 kcal.
• 3. External temperature – U-shaped curve
• a) lower than body temperature activation
of mechanisms for heat retention (e.g. tremor)
metabolic rate increases
• b) higher than body temperature increasing
temperature of body and increasing metabolic rate
4. Height, weight and body surface
5. Sex
- higher in men
6. Age
- decreases with aging
7. Emotion
- excitement increases metabolism
- adrenalin increases muscle tension at rest,
apathy and depression decrease metabolic rate
8. Body temperature
- increase for 1o C = increase for 14%
9. Thyroid hormones (T4, T3)
10. Level of adrenaline and noradrenaline in the blood
Basal metabolic rate (BMR)
is the minimal rate of energy expenditure per
unit time by endothermic animals at rest
• Lying down, calm, neutral external temperature
• 12-14 hours after meals, absence of strenuous physical work
for 24 h
• Elimination of all the negative physical and psychological
factors if possible
Basal metabolic rate (BMR)
• In humans, it correlates with the body surface heat
exchange occurs on the body surface
• What is the relationship between weight, height and
body surface?
S = 0,007184 . W0,425 . H0,725
S = body surface - m2
W = weight - kg
H = height - cm
Basal metabolic rate (BMR)
Adult male about 40 kcal/m2/h
(= about 2000 kcal / 24 h)
Women - lower
Older - lower
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
(kg) (cm) (years)
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
Harris-Benedict Equation (1919)
Basal metabolic rate (BMR)
Effect of sex
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
Man 20 years, 80 kg, 185 cm
BMR = 1950 kcal
Woman 20 years, 55 kg, 165 cm
BMR = 1395 kcal
Basal metabolic rate (BMR)
Effect of sex
Man 20 years, 80 kg, 185 cm
BMR = 1950 kcal
Woman 20 years, 80 kg, 185 cm
BMR = 1730 kcal
Difference of about 10%
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
Basal metabolic rate (BMR)
Effect of age
Man 20 years, 75 kg, 180 cm
BMR = 1860 kcal
Man 70 years, 75 kg, 180 cm
BMR = 1520 kcal
Difference of about 20%
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
Basal metabolic rate (BMR)
Effect of age
Woman 20 years, 60 kg, 165 cm
BMR = 1440 kcal
Woman 70 years, 60 kg, 165 cm
BMR = 1200 kcal
Difference of about 15%
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
Basal metabolic rate (BMR)
Effect of age
For women BMR practically unchanged between 20 and 40 years,
in men still slowly decreasing (2-3% annually).
The decrease in BMR in women between 40 and 50 years
is steeper than in men.
BMR men = 66 + (13,7 . weight) + (5,0 . height) - (6,8 . age)
BMR women = 655 + (9,6 . weight) + (1,85 . height) - (4,7 . age)
30
35
40
45
50
55
60
2 8 16 20 30 40 50 60
kcal/m2/h
AGE
BMR - DEPENDENCE ON AGE AND SEX
MEN
WOMEN
Basal metabolic rate (BMR)
Effect of age
The largest decrease of BMR
occurs in puberty
The lowest decrease of BMR in men
is between 30 and 50 years,
In women between 20 and 40 years
During menopause, BMR decreases more sharply
than in the same age for men
Basal metabolic rate (BMR)
Long-term starvation = a decrease BMR
- sympathetic activity decreases
- amount of catecholamines decreases
- production of thyroid hormones decreases
In reducing diet the initial sharp decline of body
weight is followed by its slowing
After food intake sympathetic activity increases
and BMR increases too
68
70
72
74
76
78
80
82
84
800
1200
1600
2000
Weight(kg)
BMRandEP(kcal)
BMR, EP, RUDUCING DIET AND WEIGHT
EP BMR hmotnost
Reducing diet
weight
1200
1400
1600
1800
2000
74
78
82
86
n r n r n r n r n
Weight(kg)
YO-YO EFFECT
hmotnost BMR
n = normal diet, r = reducing diet
WEIGHT
• Muscular work (both before and at measurements)
• Food intake (before measurement)
• High or low ambient temperature (curve is U-shaped)
• Height, weight, body surface
• Sex
•Testosterone - increase by 10 to 15%
•Female sex hormones insignificantly
• Age
• Emotional status
• Body temperature
• Thyroid status
•Secretion of maximal amount of thyroxine = increase by 50 – 100 %
•Adaptation of thyroid gland on different climatic conditions (increased secretion in cold areas,
and lowered secretion in warm climates) = differences in BMR
•In the polar regions BMR is increased by 10-20%
•Growth hormone
•Increase in BMR (stimulation of cell metabolism, increase muscle mass)
•Substitution therapy = 20% increase
•Amount of catecholamines in blood
•Sleep - reduction by 10 - 15% = reduction in muscle tone + decreased activity of the nervous system
•Malnutrition - prolonged malnutrition decreases BMR by up to 30%
Factors that influence basal metabolic rate
Energy balance
• The balance between energy intake and
expenditure
• Negative energy balance = internal stores are
consumed (catabolism of glycogen, proteins, and
fats)
= loss of weight
• Positive energy balance = intake of energy
predominates over energy consumption
= gaining weight
Kittnar, O. et al.
Lékařská fyziologie.
1st Ed. Grada
Publishing 2011
Energy balance
With the exception of humans
and some domesticated and hibernating animals
appetite regulates food intake
Obesity is a rarity
Over 70% of the human population
is overweight or obese
Energy expenditure
Energetic equivalent (EE)
Amount of energy (Q)
released during consumption of 1 liter of oxygen
(Q/VO2)
.
Energy expenditure
Energetic equivalent (EE)
• saccharides 21,1 kJ = 5,05 kcal
• proteins 18,0 kJ = 4,31 kcal
• fats 19,0 kJ = 4,55 kcal
incomplete catabolism
(human organism is not able to
use the energy of the nitrogen compounds)
Energy expenditure
Energetic equivalent (EE)
Mixed diet
(60% carbohydrate, 30% fat, 10% protein)
EE = 20,1 kJ = 4,81 kcal
4,8 kcal
Energy expenditure
At rest, human consumes about 3,4 - 3,6 ml
O2/kg/min
1 MET (metabolic equivalent)
What energy is it??
VO2 (women) = 3,4 . 4,8 =16,3 cal/kg/min
VO2 (men) = 3,6 . 4,8 =17,3 cal/kg/min
(lower by 5 - 15%)
The Metabolic Equivalent of Task (MET), or simply
metabolic equivalent, is a physiological measure
expressing the energy cost of physical activities and is
defined as the ratio of metabolic rate (and therefore the
rate of energy consumption) during a specific physical
activity to a reference metabolic rate, set by convention
to 3.5 ml O2·kg−1·min−1 or equivalently.
1 MET is also defined as 58.2 W/m2 (18.4 Btu/h·ft2), which is
equal to the rate of energy produced per unit surface area of an
average person seated at rest. The surface area of an average
person is 1.8 m2 (19 ft2). Metabolic rate is usually expressed in
terms of unit area of the total body surface
Energy expenditure
1 MET
the amount of oxygen that human
consumes at rest
for 1 min/1 kg of weight
About 3,5 ml/kg/min
Energy expenditure
Man 20 years, 75 kg, 180 cm
BMR = 1860 kcal (24 hod)
Calculation based on MET:
 17 cal/kg/min
 1275 cal/min
 76500 cal/h = 76,5 kcal/h
 1836 kcal/24 h
Values are approximately the same
ENERGETICKÝ VÝDEJMET VO2 (l/min) TF (/min)
Light (easy) < 3,0 < 0,5 < 90
Medium 3,0 – 4,5 0,5 – 1,0 90 – 110
Heavy 4,6 – 7,0 1,0 – 1,5 110 – 130
Very heavy 7,1 – 10,0 1,5 – 2,0 130 – 150
Exhausting > 10 > 2,0 > 150
Limits of this evaluation:
• Working capacity is not considered
At the maximum working capacity of 10
METs will work at 5 METs draw a capacity
from 50% (medium)
At the maximum working capacity of 5
METs will work at 5 METs maximum work
(exhaustive)
Limits of this evaluation:
At VO2/kg max = 50 ml/kg/min the work at
25 ml ml/kg/min draw the capacity from
50% (medium).
At VO2/kg max = 30 ml/kg/min the work at
25 ml/kg/min will draw the capacity from
83% (very heavy - exhaustive)
• Working capacity is not considered
•maximal aerobic capacity is not considered
Limits of this evaluation:
• Working capacity is not considered
• Maximal aerobic capacity is not considered
• Maximum pulse reserve is not considered
Maximum pulse reserve (MTR) = TF max - TF rest
At TF max = 200 and TF rest = 70
Work at TF = 120 will draw MTR from 38%
(120 - 70 / MTR) (light)
At TF max = 150 and TF rest = 70
Work at TF = 120 will draw MTR from 63%
(120 - 70 / MTR) (heavy)
Energy expenditure values of some activities
Light (easy) work
• driver 1,5
• laborant 2,1
• barman 2,7
• car mechanic 2,7
• serviceman 2,8
Energy expenditure values of some activities
Medium work
• electrician 3,4
• nurse 3,4
• bricklayer 4,0
• room painter 4,1
• work with a chainsaw 4,4
Energy expenditure values of some activities
Heavy work METs
• factory worker 5,4
• traditional agriculture 5,9
• coal miner 6,2
• digger 6,2
• porter of heavy loads 6,2
Energy expenditure values of some activities
Very heavy work METs
• furnace operation 7,4
• hand saw cutting 7,8
• felling of trees 8,9
• slag operation 10,1
Exhausting work
Energy expenditure values of free time
activities
METs
• sweeping, cooking, washing dishes 2,9
• window cleaning, polishing floors, shopping 3,7
• beating carpets, furniture polishing 4,5
Energy expenditure values of free time
activities
METs
• playing cards, listening music 1,5
• energetic playing musical instruments 2,7
• playing billiards 2,5
• free ballroom dancing 4,1
• folk and modern dances 6,5
• very energetic dances 11,3
Energy expenditure values of free time
activities
METs
• garthering of forest fruits (berries) 2,5
• raking leaves 3,9
• spading, hoeing 5,0
• throwing with a shovel 5 kg/10x per min 6,6
• splitting wood 6,7
• Fishing in flowing water 3,9
• fishing in the stream 5,5
Energy expenditure values for sports
METs
• Walking - speed of 5 km/h on the flat 4,1
• Walking - speed of 5 km/h uphill 8,0
• Running - speed of 8 km/h on the flat 7,3
• Marathon racing 18,4
• Cycling - 21 km/h 8,2
• Swimming - speed of 1.2 km / h (untrained) 7,1
• Competitive swimming 15,5
Energy expenditure values for sports
METs
• Football 10,0
• recreational tennis doubles 5,5
• Recreational tennis single format 8,6
• Racing tennis single format 11,0
• Ski tourism 6,5
• Racing cross-country skiing 19,7
• Lightweight ski descent 7,7
• Alpine skiing 14,0
Energy expenditure values for sports
METs
• Aerobics 5,6
• Ice hockey 25,7
• Racing rowing 23,4
• Golf 3,1
• Weight-lifting 14,4
• mountaineering 7,4
DIRECT CALORIMETRY
= measurement of energy released by burning of diet out of
body (oxidation of compounds in a calorimeter)
- Adiabatic calorimeter = the content of calorimeter is heated
- Isothermal calorimeter = heat produced is conducted away
1. Caloric bomb
2. Whole-body calorimeter (for laboratory animals, for
humans)
INDIRECT CALORIMETRY
•Amount of consumed O2.
•Amount of energy released for 1 mol of consumed O2 differs according to type of
oxidated compound (the effect of diet composition)
•Open/closed systems
- person inhales atmospheric air and exhales it into the analyzer
- person inhales oxygen from the reservoir = closed system
PRACTICALS
Barret, K.E., Boitano, S., Barman, S.M., Brooks, H.L. Ganong´s
Review of Medical Physiology. 23rd Ed. McGraw-Hill Companies
2010