every knows exercise is good for body, but this ppt gives us the knowledge about how much energy is spent by doing exercise

1. Energy expenditure at rest and during activity.
Radhika Chintamani
Energy: it is the capacity to do work.
Bioenergetics refers to: flow and exchange of energy within the living system.
Law of thermodynamics: “Energy can neither be created nor be destroyed but transfers from
one form to another without being depleted.”
This law basically describes conservation of energy principle.
Energy system=Potential energy + Kinetic energy.
Potential energy Kinetic energy
Energy spent to attain a static position by the
individual is called so. Eg: to attain a posture
i.e. standing stagnant.
Releasing potential energy it transforms into
kinetic energy. Eg: static standing to walking.
Energy spent by an individual to move a single
body part or entire body is called so. Eg:
walking.
Energy releasing and energy conserving process:
Exergonic: any physical or chemical process that releases energy to its surrounding. It is called a
downhill process as there is decline in free energy.
Equation which gives quantitative free energy value: G=H-TS.
Where G=free energy,
H= enthalpy, i.e. potential energy within a molecule’s chemical bonds,
T= Absolute temperature
S= Energy unavailable due to randomness.
Endergonic: chemical recation that store or absorb energy are called so. It is an uphill process
and proceeds with increase in free energy for biological work.
Exergonic process sometimes link with endergonic process to transfer energy from one form to
another.
Interconversions of energy: total energy in an isolated system remains constant. Net decrease
in one form of energy is accompanied with net increase in another form of energy.
Forms of energy:
1. Chemical.
2. Mechanical.

2. 3. Heat.
4. Light.
5. Electrical and
6. Nuclear.
Eg ofenergy conversions:
1. Photosynthesis:
Sun light
Nuclear fusion
Release of potential energy stored in the nucleus of hydrogen atom
Gamma radiation
Radiant energy.
2. Respiration:
In the presence of oxygen, cells extract the chemical energy stored in carb lipid and
protein molecules= cellular respiration
Release of energy
Conversion of released energy into other energy compound.
Biological work in humans:
1. Mechanical work:
 Generated by muscle cont and subsequent movt produced.
 It is the best example for transforming potential energy into the kinetic energy;
i.e. movement produced by human body during walking.
 Energy is converted by= molecular motor’s in muscle fiber protein filaments.
2. Chemical work:
 Generated by chemical work performed by cells for maintainance and growth.
 Eg: muscle tissue synthesis (hypertrophy) occurring in response to chronic
overload in resistance training.
3. Transport work:
 Generated during the movement of cellular materials from high concentration
gradient to low concentration gradient. This passive process is called diffusion.
Diffusion doesnot require energy to occur.
 Active transport: energy requiring process.
Factors affecting rate of bioenergetics:
Extra energy is lost in the form of heat
to the external environment.

3. 1. Enzymes as biologic catalyst:
 Rate limiting enzymes: +ve and –ve biofeedback process.
 Activation energy:
2. Reaction rates: not all enzymes have same reaction rates. The latency time for each
enzyme varies.
3. Mode of action:
 Active site:
 Enzyme-substrate complex:
 Lock and key mechanism:
4. Co-enzymes:
Energy transfers in the human body:
Human energy dynamic involve transfer energy via chemical bond.
Phosphate bond energy:
Energy obtained by metabolism of food is harvested in the form of adenosine triphosphate. ATP
serves as the ideal energy transfer agent. When ATP is utilized as energy for certain work, it
actually splits into two forming adenosine diphosphate (ADP) and Phosphate.(Pi). this chemical
reaction occurs in the presence of Adenosine triphosphatase.
ATP is very limitedly present in the cells. After certain amount of work, this ATP is utilized for
the carrying out of work. After some time, there is no more energy left in the cell from ATP to
carry on the work. Hence, it is necessary to resynthesize the ATP and store it in the cell.
Contributors to anaerobic and aerobic resynthesis of ATP:
Aerobic:
(citric acid cycle/respiratory chain)
Fatty acids
Pyruvate from glucose
Some deaminated amino acids.
ATP
Biologic work
Any process of resynthesis of ATP, just fills in the amount of ATP, then after filling the ATP
amount these stored ATP are further used for carrying out the work by that individual muscle.
Anaerobic:
(Glycolysis)
Phosphocreatinine.
Glucose/glycogen
Glycerol
Some deaminated amino acids
ATP
Biologic work.

4. This ATP resynthesis occurs by ATP-PCr cycle, where activated phosphate group form
phosphocreatinine is donated to ADP, to form ATP again.
There are two types of phosphorylation:
i. Substrate level phosphoryation: occurs in the absence of oxygen.
ii. Oxidative phosphorylation: occurs in the presence of oxygen.
Efficieny of oxidative phosphorylation:
- each mole of ATP formed from ADP=7kCal of energy.
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5. Energy transfer during exercise:
Immediate energy The ATP-PCr system: High intensity exercise of short duration requires an immediate
energy supply. This energy comes from intramuscular high energy sources such as ATP, PCr, and high
energy phosphate. Each kg of skeletal muscle consists of 3-8mmol of ATP and 4-5 times more PCr. The
quantity of these high energy molecules probably becomes depleted within 20-30sec of maximal exc.
Hence during last few sec runner begins to run slow.
Short-term energy: the lactic acid system: