Bioenergetics

Bioenergetics

Chemical process of converting food→ energy

METABOLISM

4 Forms of Energy

Chemical

Electrical

Heat

Mechanical

Energy in Human Physiology

ATP

2 Primary types of energy measurement

Energy for Life (survive)

Energy for activity

What metabolisms make up our energy for life?

Basal Metabolism

Resting metabolism

Basal metabolism

Direct measurement of how much energy the body needs to sustain life at rest

Resting Metabolism

Indirect measurement (estimated) of how much energy the body needs to sustain life at rest

What 2 things does Energy for Activity take into account for?

Total calories of activity

energy system used during each activity

3 energy systems for muscular activity and there function

PCR: immediate/explosive exercises

Anaerobic metabolism: sprints, short, powerful exercise

Aerobic metabolism: edurance or extended high-intensity exercises

Componenets of ENERGY EXPENDITURE

Thermal effect of food (5-10%)

Basal Metbaolic Rate (60-70%)

Physical Activity (10-40%)

Calorie

1 gram increases temperature of 1 gram of water by 1 degree Celsius

1000 calorie=1kilocalorie

Measurement of Work

Not same as measurment of energy expenditure in context of physical activity/exercise

Isometric muscle contractions=no work produced

Calorimetry

measure energy expenditure

Direct Calorimetry

Measures heat produced from energy

Bomb calorimeter

Roo calorimeter: mesaures patients energy expenditure/metabolism based off of difference between O2 and CO2 concentrations consumed and expelled

Indirect Calorimetry

measures gas exchange which estimates energy production

Laboratory procedures

2 ways to assess indirect calorimetery for humans

Laboratory conditions

Real Life conditions

Laboratory conditions for indirect calorimetry

measurment of oxygen uptake and carbon dioxide production

Indirect calorimetry real life conditions

Doubly labeled water technique

Stable isotopes of hydrogen and oxygen are ingested

Analysis of urine and blood for hydrogen and oxygen to measure carbon dioxide fluctuation

Factors that affect REE

• Age

• Gender: 10-15% Lower in Females

• Hormones

• Body Surface Area

• Exposure to cold or hot weather increases REE

• Increased ventilation due to altitude increases REE

• Caffeine: stimulant that increases REE by up to 10%

• Body composition: Fat free to Fat mass ratio

• Losing body weight (fat and muscle) lowers REE

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

• If REE is declining with age it may be associated with loss of muscle

• Very low Calories diets decrease REE

DIET at rest

Aerobic energy system sustains life at rest (60% fat 40% from carbs)

Fat allows more utilization of it at rest and during exercise)

spares limited carb stores, enhances endurance, provides limitless energy reserve

Physical Activity

increases metabolic rates

intensity of it is most important factor affecting metabolic rate

VO2 Max and Nutrition

shows maximum amount of oxygen utilization during endurance exercise

tests aerobic/cardiovascular fitness

percentage of carbs: fat usage at various intervals/intensities

Calorie expenditure at various intervals/intensities

What does a VO2 max not tell us?

Protein metabolism

Nitrogen on protein inhibits machines ability to calculate

Perforamnce

Reflective of energy cost during specific exercise tested

Does tell how many calories were used but doesnt say houw much calories an athlete should consume overall

What rae graded exercise tests based off of

ratio of O2":CO2

Average oxygen consumption

5 calories for every liter of oxygen consumed

body must generate enough energy/ATP to sustain this

Calories per gram

Carbs: anaerobic and aerobic metabolism→ 4kcal/gram

Fat→aerobic metabolism→9kcal/gram

Protein→4kcal/gram

alcohol→anaerobic metabolism→7kcal/gram

activity and oxygen consumption

Increase in activity increases oxygen consumption; increases calorie expenditure

Where do calories come from?

breakdown of fat, carbs and protein

Diet based on activity type

Highly aerobic: more fat diet

Highly anaerobic: more carb diet

sum total of all physical and chemical changes that take place within body

Metabolism

Anabolic vs Catablic metabolism

Anabolic: constructive

Catabolic: breakdown process

Breakdown of nutrients

Carbs, fats and protein all break down into acetyle coA

Carbs=glucose

Fat=fatty acids

protein=amino acids

Energy process for metabolic activity

Acetyl coA→substrate that enters Krebs cycle→ETC→ATP

Adenosine Triphosphate(ATP)

Most important energy olecule in cells

Product of aerobic and anaerobic metabolism

Composed of Adenine, Ribose, 3 phopshate molecules

Adenosine diphsophate (ADP)

Pi is inorganic phosphate

Breaking down ATP

releases energy into cell

increases acidity due to increase in H+

ATP production timeline

Short high intensity exercises (sprinting, weightlifting) body uses abnaerobic metabolism (no oxygen)

First 30 seconds (ATP-PC system)

30 seconds→ 3 minutes: glycolysis

Anything longer than 3 min Utes: aerobic metabolism (requires oxygen, occurs in mitochondria)

Energy storage in the body

• ATP: 1 calorie, 17.5 yards

• Phospocreatine (PCr): 4 calories, 70 yards

• Carbohydrate->glycogen: 1,500 calories, 15 miles

• Fat->Adipose tissue, 80,000 calories, 800 miles

• Protein->amino acid pool 30,000 calories, 300 miles

Human Energy Systems

• Anaerobic power (ATP-PCr; phosphagen) 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) 42.2-1000 kilometers (125-360 minutes)

Human Energy

helps define personalized training, dietary, and supplemental programs

Energy systems for muscular activity

designed to produce energy during rest and physical activity (work)