WEEK 4 HUMAN ENERGY

Human Energy

• HSCI 4662

Measures of Energy

• Energy forms:

  • Mechanical

  • Chemical

  • Heat

  • Electrical

  • Light

  • Nuclear

• For sport purposes, mechanical, chemical, and heat energy are most important.

Energy Sources

• Sun (solar energy)

• Animals (chemical energy):

  • Carbohydrates

  • Fats

  • Protein

• Plants (chemical energy):

  • Carbohydrates

  • Fats

  • Protein

• Humans (chemical energy):

  • Carbohydrates

  • Fats

  • Protein

  • ATP-PCr

Human Energy Types

• Mechanical energy: Capacity to do metabolic work.

• Chemical energy: Storage form of energy.

• Heat energy: Product of metabolism.

Measuring Work, Physical Activity, and Energy Expenditure

• Work and power:

  • Work = force x distance

  • Power = work/time

• Measurement systems:

  • English

  • Metric

  • International (SI)

Energy Measurement Systems

• Terms in English, metric, and international systems:

  • Mass: slug, kilogram (kg), kilogram (kg)

  • Distance: foot (ft), meter (m), meter (m)

  • Time: second (s), second (s), second (s)

  • Force: pound (lb), newton (N), newton (N)

  • Work: foot-pound (ft-lb), kilogram-meter (kgm), Joule (J)

  • Power: horsepower (hp), watt (W), watt (W)

Work and Power Measurement

• Interrelationships between work measurement systems:

  • Weight:

    • 1 kilogram = 2.2 pounds

    • 1 kilogram = 1,000 grams

    • 454 grams = 1 pound

    • 1 pound = 16 ounces

    • 1 ounce = 28.4 grams

    • 3.5 ounces = 100 grams

    • 1 newton = 0.102 kg

  • Distance:

    • 1 meter = 3.28 feet

    • 1 meter = 1.09 yards

    • 1 foot = 0.30 meter

    • 1,000 meters = 1 kilometer

    • 1 kilometer = 0.6215 mile

    • 1 mile = 1.61 kilometers

    • 1 inch = 2.54 centimeters

    • 1 centimeter = 0.39 Inch

  • Work:

    • 1 kgm = 7.23 foot-pounds

    • 1 kgm = 9.8 joules

    • 1 foot-pound = 0.138 kgm

    • 1 foot-pound = 1.35 Joules

    • 1 joule = 1 newton meter

    • 1 kilojoule = 1,000 Joules

    • 1 megajoule = 1,000,000 joules

    • 1 joule = 0.102 kgm

    • 1 joule = 0.736 foot-pound

    • 1 kilojoule = 102 kgm

  • Power:

    • 1 watt = 1 joule per second

    • 1 watt = 6.12 kgm per minute

    • 1 watt = 0.0013 horsepower

    • 1 horsepower = 550 foot-pounds per second

    • 1 horsepower = 33,000 foot-pounds per minute

    • 1 horsepower = 745.8 watts

Measurement of Work and Physical Activity

• Ergometer to measure work output:

  • Cycle

  • Arm

• Devices to measure physical activity:

  • Pedometer

  • Accelerometer

  • Intelligent Device for Energy Expenditure and Activity

  • Global Positioning Systems

Measurement of Energy Expenditure

• Measurement of work is not the same as measurement of energy expenditure.

• Isometric muscle contraction: no work produced.

• Calorimetry measures energy expenditure:

  • Direct calorimetry

  • Indirect calorimetry

Direct Calorimetry

• Involves measuring heat production in a chamber with insulation, a thermometer, an air space, a wire to ignite food, and water.

Indirect Calorimetry

• Laboratory conditions: Measurement of oxygen uptake and carbon dioxide production.

• Real-life conditions: Doubly labeled water technique with stable isotopes of hydrogen and oxygen ingested, followed by analysis of urine and blood for hydrogen and oxygen to measure carbon dioxide fluctuation.

Commonly Used Measure of Energy

• In the United States, the Calorie.

• In most of the world, the joule.

• 1 gram calorie will increase the temperature of 1 gram of water 1 degree Celsius.

• 1000 gram calories = 1 kilocalorie.

• Kilocalorie (Calorie or ,C,) is the most common measure of energy.

The Calorie

• Some approximations of 1 Calorie (kilocalorie):

  • $3,086$ foot-pounds

  • $427$ kilogram-meters

  • $4.2$ kilojoules (kJ) or $4,200$ joules

  • $200$ milliliters of oxygen (approximately)

• Calories in macronutrients and alcohol.

Calories in Macronutrients and Alcohol

• $4.30C$: One gram of carbohydrate

• $9.45C$: One gram of fat

• $5.65C$: One gram of protein

• $7.00C$: One gram of alcohol

Atwater Factors

• Energy values in foods:

  • $4.00C$: One gram of carbohydrate

  • $9.00C$: One gram of fat

  • $4.00C$: One gram of protein

  • $7.00C$: One gram of alcohol

Calories in Food

• The Calories in 8 ounces of orange juice provides enough energy for the average male to run a mile.

Human Energy Systems

• Energy systems for muscular activity in the human body are designed to produce energy for work at varying rates.

How Energy is Stored in the Body

• Adenosinetriphosphate (ATP)

• Phosphocreatine (PCr)

• Carbohydrate

• Fat

• Protein

Energy for Metabolic Activity

• ATP is the immediate source of energy for metabolic activity, including muscle contraction.

• PCr can regenerate ATP rapidly.

• Both ATP and PCr are in very short supply.

• Carbohydrate, fat, and protein can be metabolized to produce ATP and PCr but takes more time.

Energy Pathways

• Protein

• Carbohydrate (Glucose)

• Fat (Fatty acids)

• Acetyl CoA

• Krebs cycle

• ATP

• Electron transport chain

Major Energy Stores

• Major energy stores in the human body with approximate total caloric value:

  • ATP:

    • Major storage form: Tissues

    • Total body Calories: 4.2

    • Total body kilojoules: 16.8

    • Distance covered: 17.5 yards

  • PCr:

    • Major storage form: Tissues

    • Total body Calories: 16.8

    • Total body kilojoules: 70

    • Distance covered: 70 yards

  • Carbohydrate:

    • Serum glucose:

      • Total body Calories: 20

      • Total body kilojoules: 88

      • Distance covered: 350 yards

    • Liver glycogen:

      • Total body Calories: 400

      • Total body kilojoules: 1,680

      • Distance covered: 4 miles

    • Muscle glycogen:

      • Total body Calories: 1,500

      • Total body kilojoules: 6,300

      • Distance covered: 15 miles

  • Fat:

    • Serum-free fatty acids:

      • Total body Calories: 7

      • Total body kilojoules: 29.2

      • Distance covered: 123 yards

    • Serum triglycerides:

      • Total body Calories: 75

      • Total body kilojoules: 315

      • Distance covered: 0.75 mile

    • Muscle triglycerides:

      • Total body Calories: 2,500

      • Total body kilojoules: 10,500

      • Distance covered: 25 miles

    • Adipose tissue triglycerides:

      • Total body Calories: 80,000

      • Total body kilojoules: 336,000

      • Distance covered: 800 miles

  • Protein:

    • Muscle protein:

      • Total body Calories: 30,000

      • Total body kilojoules: 126,000

      • Distance covered: 300 miles

Human Energy Systems for Runners

• Anaerobic power (ATP-PCr): 60-200 meters (6-20 seconds)

• Anaerobic capacity (anaerobic glycolysis; lactic acid): 400-800 meters (43-103 seconds)

• Aerobic power (aerobic glycolysis): 5,000-10,000 meters (12-26 minutes)

• Aerobic capacity (aerobic lipolysis): 42.2-100 kilometers (125-360 minutes)

The ATP-PCr Energy System

• Adenosine Triphosphate

  • Adenosine with 3 high energy phosphate bonds

• Energy is released when a phosphate bond is broken for muscle contraction

The ATP-PCr Energy System

• Phosphocreatine (PCr)

  • Creatine with a high-energy phosphate bond.

• PCr donates its phosphate to ADP to regenerate ATP.

The Lactic Acid Energy System (Anaerobic Glycolysis)

• Glycolysis converts carbohydrate (glycogen) to lactic acid, producing ATP.

Energy Pathways of Carbohydrate, Fat, and Protein

• Glycolysis: Glucose to Pyruvate

  • Takes place in the cytosol of the cell.

  • Enzymes in the cytosol participate at the following steps:

    • Hexokinase

    • Phosphohexose isomerase

    • Phosphofructokinase

    • Aldolase

    • Phosphotriose isomerase

    • Glyceraldehyde-3-phosphate dehydrogenase

    • Phosphoglycerate kinase

    • Phosphoglycerate mutase

    • Enolase

    • Pyruvate kinase

    • Lactate dehydrogenase is used to recycle NADH + H+ back to NAD (anaerobic glycolysis).

  • Presents a phosphate group.

  • Addition of phosphorus to glucose by ATP

  • Glucose activates the 6-carbon glucose molecule.

  • The later metabolism of fructose 6-phosphate to fructose 1-6 bisphosphate uses another ATP.

  • The 6-carbon molecule, fructose 1,6-bisphosphate, is split into two 3-carbon molecules: one is glyceraldehyde 3-phosphate, and the other is eventually converted into that product as well.

  • The conversion of each pyruvate to lactate allows a cell to recycle NADH + H+ back to NAD. This then allows glycolysis to continue, as NAD is needed. This latter pathway occurs primarily in only a few types of cells, such as red blood cells, and under high-in anaerobic conditions such as very intense exercise.

  • Metabolism of each 1,3-bisphosphoglycerate to 3-phosphoglycerate results in the synthesis of ATP.

  • Metabolism of each phosphoenolpyruvate to pyruvate results in the synthesis of another ATP.

  • Pyruvate can undergo further metabolism to enter the citric acid cycle, which occurs in the mitochondria.

The Oxygen Energy System

• Aerobic glycolysis: Oxidation of glycogen or glucose.

• Aerobic lipolysis: Oxidation of fatty acids (beta oxidation).

• Aerobic proteolysis (limited energy production): Oxidation of glucogenic or ketogenic amino acids.

Respiration and Circulation

• Lungs take in oxygen from the atmosphere.

• Central circulation: Heart pumps oxygen-enriched blood.

• Peripheral circulation: Arteries carry oxygen-rich blood to muscle tissues.

• Metabolism: Muscle cells take in and use oxygen to produce energy (ATP) from carbohydrates and fats.

Muscle Metabolism

• Muscle protein (Amino acids)

• Muscle glycogen (Glucose)

• Muscle triglycerides (FFA)

• Krebs cycle occurs

• $CO<em>2$ and $H</em>2O$ are produced

• Electron transport (ETS)

• $O_2$

• ATP produced

Energy Production Overview

• Liver (Glucose)

• Adipose tissue (Triglycerides)

• Active muscle (Amino acids, Glucose, Free fatty acids, Oxygen, Muscle glycogen)

• Lungs (Oxygen)

• Blood transports Glucose, Free fatty acids, Amino acids, and Oxygen.

• Muscle: Acetyl CoA, Krebs cycle, Electron transport system produces $CO<em>2$, $H</em>2O$, and ATP

• ATP is used for muscle contraction

• Phosphocreatine (PCr) provides energy for muscle contraction

Transition Reaction

• Pyruvate is first metabolized in a transition reaction to acetyl-CoA.

• It is acetyl-CoA that actually enters the citric acid cycle. In the process, NADH + H+ is produced and $CO_2$ is lost.

• Acetyl CoA may also be generated from fatty acids and amino acids to serve as a source of energy.

• Conversion of pyruvate to acetyl CoA by PDH

The Citric Acid Cycle (Krebs Cycle)

• The citric acid cycle begins when an acetyl group carried by CoA combines with a C4 oxaloacetate molecule to form citrate.

• Oxaloacetate is re-formed during the final step of the cycle.

• Twice over, substrates are oxidized, NAD+ is reduced to NADH + H+ and $CO_2$ is released.

• ATP eventually is made as energy is released from the breakdown of an intermediate in the cycle.

• Once again an intermediate in the cycle is oxidized, and NAD+ is reduced to NADH + H+.

• Again an intermediate in the cycle is oxidized, but this time FAD is reduced to FADH2.

Electron Transport System

• Electrons move from one molecular complex to the other, hydrogen ions ($H^+$) are pumped from the mitochondrial matrix into the intermembrane space (steps 1-4).

• Hydrogen ions flow down a concentration gradient from the intermembrane space into the mitochondrial matrix; ATP is then synthesized by the enzyme ATP synthase (step 5).

• ATP leaves the mitochondrial matrix by way of a channel protein.

Energy Pathways for Fatty Acids

• Triglycerides in adipose tissue are catabolized by hormone-sensitive lipase, with fatty acids released to plasma and binding to albumin; glycerol component is transported to the liver for metabolism.

• A receptor at the muscle cell transports the fatty acid into the muscle cell where it is converted into fatty acyl CoA by an enzyme (fatty acyl CoA synthetase).

• Fatty acyl CoA is transported into the mitochondria with carnitine as a carrier.

• Fatty acyl CoA then undergoes beta-oxidation, splitting off acetyl CoA units for entrance into the Krebs cycle.

Lipoproteins and Lipid Metabolism

• Chylomicrons carry absorbed fat to body cells.

• VLDL carries fat taken up from the bloodstream by the liver, as well as any fat made by the liver, to body cells.

• LDL arises from VLDL and carries mostly cholesterol to cells.

• HDL arises from body cells, mostly in the liver and intestine and buds off other lipoproteins. HDL carries cholesterol from cells to other lipoproteins and to the liver for excretion.

• Intermediate Density Lipoprotein (IDL)

Nutrients for Human Energy Systems

• Water: Involved in hydrolysis.

• Vitamins: B vitamins, as coenzymes, are involved in many energy processes.

• Minerals: Minerals, as metalloenzymes, are also involved in energy processes; iron is part of hemoglobin to transport oxygen.

Dietary Supplements

• Carnitine, coenzyme Q10, and others marketed to athletes

Human Energy Metabolism during Rest

• What is metabolism?

  • Basal Metabolic Rate (BMR): Resting; post-absorptive; Maintain basal metabolism; Only sleeping metabolism is lower.

  • Basal Energy Expenditure (BEE): BMR extrapolated over 24 hours.

  • Resting Metabolic Rate (RMR): BMR + small amounts due to prior activity.

  • Resting Energy Expenditure (REE): RMR extrapolated over 24 hours.

Human Energy Metabolism

• What is metabolism?

  • Thermic Effect of food (TEF): Also known as Dietary Induced Thermogenesis (DIT); Post-meal elevation in RMR due to digestive processes.

Human Energy Metabolism

• What is metabolism?

  • Thermic Effect of Exercise (TEE): Also known as Exercise Metabolic Rate (EMR); Increase in metabolic rate associated with exercise; Metabolic aftereffects of exercise

  • Total Daily Energy Expenditure (TDEE) = sum of BEE (REE), TEE, and TEF

Human Energy Metabolism

• What is metabolism?

  • Metabolism represents the sum total of all physical and chemical changes that take place within the body.

  • Anabolic metabolism (anabolism): Constructive processes

  • Catabolic metabolism (catabolism): Disintegration processes

Metabolism

• Total Daily Energy Expenditure (TDEE):

  • Basal and resting energy expenditure

  • Thermic effect of food

  • Thermic effect of exercise

Factors Affecting Energy Expenditure During Rest

• Basal metabolism:

  • Basal metabolic rate (BMR): Energy needed to stay alive when awake; Only sleeping metabolic rate is lower

  • Basal energy expenditure (BEE): Basal metabolism over 24-hour period

Factors Affecting Energy Expenditure During Rest

• Resting metabolism:

  • Resting metabolic rate (RMR): BMR plus small amounts associated with eating, prior activity; About 10 percent higher than BMR

  • Resting energy expenditure (REE): Resting metabolism over 24 hour period

Effect of Eating on Metabolic Rate

• Metabolic rate is elevated after a meal

• Specific dynamic action

• Dietary-induced thermogenesis

• Thermic effect of food (TEF)

Effect of Eating on Metabolic Rate

• TEF is expressed as the % of meal energy content

  • 5-10% for a mixed meal

  • TEF may be a consideration in some weight-control diets

Estimating Daily Resting Energy Expenditure

• Estimate not as accurate as BMR test

• May be useful for weight control programs

• Other methods include effects of daily activity

Estimating Daily Resting Energy Expenditure

• Simple methods to estimate RMR

  • 1 Calorie/kilogram body weight per hour

  • Various formulae

Estimation of RMR (Males)

• Equations for Males (based on age in years):

  • 3-9: $(22.7 \;\text{x body weight*}) + 495$

  • 10-17: $(17.5 \;\text{x body weight}) + 651$

  • 18-29: $(15.3 \;\text{x body weight}) + 679$

  • 30-60: $(11.6 \;\text{x body weight}) + 879$

  • > 60: $(13.5 \;\text{x body weight}) + 487$

• Example: 154-lb male, age 20

  • 154 lbs/2.2 = 70 kg

  • $(15.3 \;\text{x 70}) + 679 = 1,750$

Estimation of RMR (Females)

• Equations for Females (based on age in years):

  • 3-9: $(22.5 \;\text{x body weight*}) + 499$

  • 10-17: $(12.2 \;\text{x body weight}) + 746$

  • 18-29: $(14.7 \;\text{x body weight}) + 496$

  • 30-60: $(8.7 \;\text{x body weight}) + 829$

  • >60: $(10.5 \;\text{x body weight}) + 596$

• Example: 121-lb female, age 20

  • 121 lbs/2.2 = 55 kg

  • $(14.7 \;\text{x 55}) + 496 = 1.304$

RMR Range of Values

• To get a range of values, add or subtract a normal 10-percent variation to the RMR estimate.

• Male example: 10 percent of 1,750 = 175 Calories

  • Normal range = 1,575-1,925 Calories/day

• Female example: 10 percent of 1,304 = 130 Calories

  • Normal range = 1,174-1,434 Calories/day

Genetic Factors Affecting REE

• Age: Infancy through adulthood

• Gender: Females REE about 10-15% lower

• Natural hormonal activity

• Body surface area

• Genetically lean versus stout

Body Composition and REE

• Body composition: Muscle versus fat

• Losing body weight, both fat and muscle, lowers REE

• Maintaining normal body weight while reducing body fat and increasing muscle mass may raise REE

• Decline in REE with aging may be associated with loss of muscle mass

Environmental Factors Influencing REE

• Exposure to cold weather: Thermogenesis

• Exposure to warm or hot weather: Sweating and cardiovascular demands

• Exposure to altitude: Increased ventilation

Environmental Factors Influencing REE

• Cigarette smoking: Nicotine

• Caffeine: One study found increases of 10 percent

Energy Sources Used During Rest

• The oxygen energy system prevails during rest

  • About 60 percent of energy from fat

  • About 40 percent of energy from carbohydrate

  • Small amount of energy from protein

Energy Sources Used During Rest

• The diet may affect the energy source during rest

  • Eating a diet rich in carbohydrate or fat will, respectively, increase energy production from carbohydrate and fat

Human Energy Metabolism during Exercise

• Exercise stresses most body systems

• Neuromuscular system determines the energy system to be used during exercise

Muscle Influence on Energy Production During Exercise

• Skeletal muscle fiber (cell) with Sarcolemma and Nucleus

• Skeletal muscle (Epimysium, Perimysium, Connective tissue)

• Bundle (a group of muscle fibers)

• Myofibril myofilaments (Sarcomere)

• Actin and myosin

Muscle Fiber Types

• Three main types of muscle fibers

  • Type I: Slow twitch red fiber; Slow oxidative (SO)

  • Type IIa: Fast twitch red fiber; Fast oxidative-glycolytic (FOG)

  • Type IIb (IIx): Fast twitch white fiber; Fast glycolytic (FG)

Muscle Fiber Types Characteristics

• Type I

  • Twitch speed: Slow

  • Color: Red

  • Size (diameter): Small

  • Fatigability: Slow

  • Force production: Low

  • Oxidative processes: Highest

  • Mitochondria: Highest

  • Myoglobin: Highest

  • Blood flow: Highest

  • Triglyceride use: Highest

  • Glycogen use: Lowest

  • Phosphocreatine levels: Lowest

  • Energy for sports: Aerobic capacity; aerobic power

• Type IIa

  • Twitch speed: Faster

  • Color: Red

  • Size (diameter): Medium

  • Fatigability: Moderate

  • Force production: High

  • Oxidative processes: Moderate

  • Mitochondria: Moderate

  • Myoglobin: Moderate

  • Blood flow: Moderate

  • Triglyceride use: Moderate

  • Glycogen use: Moderate

  • Phosphocreatine levels: Higher

  • Energy for sports: Aerobic power; anaerobic capacity

• Type IIb (IIx)

  • Twitch speed: Fastest

  • Color: White

  • Size (diameter): Large

  • Fatigability: Fast

  • Force production: Highest

  • Oxidative processes: Lowest

  • Mitochondria: Low

  • Myoglobin: Low

  • Blood flow: Lowest

  • Triglyceride use: Lowest

  • Glycogen use: Highest

  • Phosphocreatine levels: Higher

  • Energy for sports: Anaerobic power; anaerobic capacity

Muscular Exercise and Metabolic Rate

• All physical activity increases the metabolic rate

  • Activities of daily living (ADL)

  • NonExercise Activity Thermogenesis (NEAT)

  • Planned exercise activity

  • Exercise metabolic rate (EMR)

  • Thermic effect of exercise (TEE)

Exercise Intensity and Metabolic Rate

• Caloric expenditure per minute at different intensity levels relative to resting metabolic rate:

  • Resting metabolic rate: 1.0

  • Sitting and writing: 2.0

  • Walking at 2 mph: 3.3

  • Walking at 3 mph: 4.2

  • Running at 5 mph: 9.4

  • Running at 10 mph: 18.8

  • Running at 15 mph: 29.3

  • Running at 20 mph: 38.7

  • Maximal power weightlift: >90.0

Measuring Exercise Intensity

• Actual work output: Ergometer (watts)

• Physiological cost of the activity:

  • ATP-PCr energy system

    • Muscle biopsy

    • Computerized imaging procedures

Measuring Exercise Intensity

• Lactic acid energy system

  • Onset of blood lactic acid (OBLA); steady-state threshold

• Oxygen energy system

  • Oxygen uptake; maximal oxygen uptake ($VO_2max$)

$VO_2 max$ Example

• 3.6 L (3600 ml) = 60 kg body weight, $VO<em>2 max$: 60 ml $O</em>2$/kg/minute

• 4.0 L (4000 ml) = 60 kg body weight, $VO<em>2 max$: 66 ml $O</em>2$/kg/minute

$VO_2 max$Training

• Training increases $VO_2 max$

• Relationship between $VO_2 max$ and Steady state threshold

  • Steady state occurs at 50% of $VO_2 max$

  • Stead state threshold occurs at 80% of $VO_2 max$

Expressing Energy Expenditure of Exercise Metabolism

• Calories

• Kilojoules

• Oxygen uptake

• METS (One metabolic equivalent (MET) is defined as the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml $O_2$ per kg body weight x min.)

• Multiples of the RMR

Energy Expenditure Constants

• 1 MET = 3.5 ml $O_2$/kg body weight/minute

• Heat to raise 1 kg of water 1°

• 1 Calorie = 4.2 kilojoules (kJ)

Energy Expenditure

• 1 MET resting oxygen uptake

  • 3.5 ml $O<em>2$ x 70 kg = 245 ml $O</em>2$ per minute

• 1 Liter Oxygen = 5 Calories (kilocalories)

• 1 Liter Oxygen = 1000 milliliters

• 245/1000 = 0.245 liter oxygen per minute @ 1 MET

• 0.245 L x 5 Calories/L = 1.225 Calories/minute

Exercise Energy Equivalencies

Energy Interconversions Scenario

• A sedentary, untrained, 80-kg male is running 12 minutes per mile (5 mph) and is consuming 3.36 liters of oxygen per minute. Assume the following:

  • 1 Calorie (C) = 4 Kilojoules (kJ)

  • 1 liter oxygen = 5 Calories

  • 1 MET = 3.5 ml oxygen/kilogram/minute

Energy Interconversions

• Assume the following:

  • 1 Calorie (C) = 4 Kilojoules (kJ)

  • 1 liter oxygen = 5 Calories

  • 1 MET = 3.5 ml oxygen/kilogram/minute

• Calculate the following:

  • Calories per minute he is using

  • Kilojoules per minute he is using

  • MET level at which he is exercising

Metabolic Rate During Exercise

• Oxygen consumption is precise, but not very practical

• Other physiological measures

  • Heart rate

  • Respiratory rate

Physiological Response vs Exercise Intensity

• Low Intensity Exercise

  • Low Oxygen consumption

  • Low Heart Rate

  • Low Respiration

• High Intensity Exercise

  • Maximal Oxygen consumption

  • Maximal Heart Rate

  • Maximal Respiration

Determining the Energy Cost of Exercise

• Example with body weight in kilograms and pounds, and energy expenditure for different activities like skiing, soccer, squash, and swimming.

Activities to Increase Energy Expenditure

• Activities involving large muscle groups

  • Walking

  • Running

  • Swimming

  • Cycling

  • Group Exercise

Activities to Increase Energy Expenditure

• Activities involving large muscle groups

  • Home exercise equipment

  • Resistance or weight training (lower than aerobic)

  • Passive and occupational energy expenditure

• Intensity and duration

Classification of Physical Activities Based on Energy Expenditure

• Light, mild aerobic exercise (<5 Calories/min)

  • Archery

  • Badminton, social

  • Baseball

  • Bicycling