Want to understand how the human body captures, stores and uses energy?

This applied biology course has very practical application for not only sportsmen and women, coaches and fitness leaders; but anyone who is concerned about managing and improving the work output of a human body.

Prerequisites: A basic understanding of body systems (e.g. Human Biology IA).

Learn to understand and manage energy systems in the human body.

Bioenergetics studies the metabolic pathways that energy follows through the body in order to give us the necessary fuel to make the human body function, both internally and externally.


There are 7 lessons as follows:

  1. Energy and Work -
    Explains how energy is used in the human body to create work and power
  2. Energy Pathways -
    Looks at energy pathways during rest, work and recovery
  3. The Acid-Base Balance -
    Explains the significance of the acid-base balance in the body
  4. Osmosis & Diffusion -
    Explains movement of materials in and out of living cells
  5. Atmospheric Pressure -
    Examines the affect of changing atmospheric pressure on the human body
  6. Temperature Regulation -
    Centres on temperature regulation in the body
  7. Ergogenic Aids to Performance -
    Examines ergogenic aids to body performance during activity/exercise

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

On successful completion of the course you should be able to do the following:

  • Explain how energy is used in the human body to create work and power.
  • Explain energy pathways during resting, work and recovery.
  • Explain the significance of the acid-base balance in the body.
  • Explain movement of materials in and out of living cells.
  • Explain the affect of changing atmospheric pressure on the body.
  • Explain temperature regulation in the body.
  • Explain ergogenic aids to body performance during activity/exercise.

Here are just some of the things you may be doing:

  • Explain biological energy cycles, using illustrations where appropriate.
  • Explain two examples of energy pathways in the body, including an anaerobic and an aerobic pathway.
  • Explain the function of ATP in body energy pathways.
  • Explain the significance of the following terms to understanding body energy pathways:
    • energy
    • work
    • power
    • efficiency during exercise
  • Explain the consumption of oxygen during different stages of activity, including:
    • at rest
    • warming up
    • peak activity
    • cooling down
  • Calculate the net cost of exercise in litres per minute, for a set situation.
  • Explain the measurement of efficiency during the exercise carried out in a set task.
  • Explain problems which may occur in physiological processes during running a marathon.
  • Explain in one paragraph for each, the following acid-base terms with relevance to exercise:
    • Buffer
    • Alkali reserve
    • Alkalosis
    • Acidosis
  • Describe respiratory regulation of pH in the human body.
  • Describe how regulation of pH occurs in the kidneys.
  • Explain the affect of strenuous exercise on body pH.
  • Explain osmosis in a specific biological situation (of your choice).
  • Distinguish between diffusion and facilitated diffusion in the human body.
  • Explain how electrochemical forces maintain cellular equilibrium.
  • Explain how active transport mechanisms occur at a cellular level.
  • Describe three situations where pressure changes can affect body function, including:
    • scuba diving
    • mountain climbing
  • Explain the effects of pressure changes on different parts of the body, including examples of changes due to altitude and scuba diving.
  • Explain the effect of a decompression treatment on a diver suffering from nitrogen narcosis.
  • List mechanisms of heat loss in the human body.
  • List mechanisms of heat gain in the human body.
  • Explain the operation of thermal receptors and effectors in the human body.
  • Describe the exercise session which you underwent in your set task, and explain the maintenance of body temperature during that exercise session.
  • Explain how temperature regulation may be different during peak exercise, to what it may be during exercise at 60-70% effort.
  • Explain the affects of steroids on the body, in relation to both performance, and other health factors, during two different types of activity.
  • Explain the affect of amphetamines, and other performance enhancing drugs on the body, during an activity of your choice.
  • Compare the advantages and disadvantages of amino acid use to enhance physical activity.
  • Explain the use of blood doping to enhance physical performance in a specific activity.
  • Explain ways oxygen can be used to enhance performance in a specific activity.
  • Explain the effect of different vitamins on three different types of performance.
  • Explain the affect of aspartic acid salts on a specific performance.



As exercise starts:

• Heart rate and respiration rate increase
• VO2 increases
• Lactate initially increases
• RQ drops at first, then increases

As intensity of exercise increases, the use of fat decreases; and at 50% VO2 max, fat use can reach zero.

Metabolic pathways involved in the transition from exercise to rest are different to those involved from rest to exercise. The purpose of this recovery phase is to return the body to its pre exercise condition. To do this the following needs to be achieved:

• Replenish energy stores depleted by exercise.
• Remove any build up of lactic acid (ie. lactates).

As exercise slows, energy demand decreases, although oxygen consumption continues at a higher than normal level for a period. The body goes into "oxygen debt", which is a term used to describe any excess of oxygen consumed during recovery which is over that normally consumed at rest. For the first 2 or 3 minutes following exercise there can be a high rate of oxygen consumption. After this, oxygen consumption declines slowly to near pre exercise levels.

Oxygen debt is NOT simply oxygen required to replace oxygen stores which were used during exercise. In fact very little oxygen from the muscles needs replacing. It is the sources of energy (ie. ATP, PC and glycogen) which need to be replenished and oxygen is needed to fuel this replenishment.

Alactacid oxygen debt component
This refers to the rapid breathing phase in perhaps the first 2 or 3 minutes following exercise. During this period the oxygen debt is used to replenish muscular stores of ATP and PC.
The alactacid debt may range from 2 to 2.5 litres.

Lantacid oxygen debt component
This is the slower phase of recovery where oxygen consumption gradually decreases. Lactic acid is removed in this phase. This phase is about 30 times slower than the alactacid phase, because it takes longer to metabolise lactic acid and restore phosphagens. Light exercise will however speed up this phase.

Replenishing Muscular Glycogen
This was once thought to occur during the lantacid oxygen debt period, but that is largely untrue. Muscle glycogen can take at least 2 days to resynthesise, and is affected largely by diet.
Muscle glycogen may increase to more than double normal levels by firstly depleting stores through strenuous exercise and a low carbohydrate diet; then following that exercise with rest and a high carbohydrate diet.