Energy & Calories (AQA GCSE Physical Education (PE))

Energy Use

• All living organisms require energy to survive. This energy comes from an essential chemical reaction that takes place in all living cells called respiration

• Glucose is a reactant for respiration that stores chemical energy. When glucose is broken down during respiration the energy is released in a usable form

• To get glucose into the body it must be consumed in the food we eat

• Energy is measured in calories and has the unit Kcal

• Different people have different day-to-day energy requirements

• This varies depending on factors such as:

  • Age:

    • Young children require a lot of energy because they are very active and use energy for growing

    • Adults require less energy because as you age, your body replaces muscle with fat and fat burns fewer calories

  • Gender:

    • The average adult male requires 2,500 Kcal/day

    • The average adult female requires 2,000 Kcal/day

  • Height:

    • Taller people require more energy than shorter people because they have more body cells that are respiring

  • Energy expenditure:

    • Exercise burns calories

    • The more exercise a person carries out, the higher the energy requirement

    • People who live a sedentary lifestyle require very little