1. Energy in the Body

2. Getting Energy from Food: Energy Inputs
The chemical energy in food provides the necessary energy input for your body to function.

3. Getting Energy from Food: Energy Inputs
Chemical energy in food is broken down into simpler molecules such as glucose and glycogen. They are metabolized in the cells by combining with oxygen.
Oxidation reactions “burn” the fuel you obtain by eating.

4. Getting Energy from Food: Energy Inputs

5. Getting Energy from Food: Energy Inputs

6. Using Energy in the Body: Energy Outputs
At rest, your body uses energy to build and repair tissue, digest food and keep warm.
Your body uses approximately 100 W of energy at rest.
The energy is converted almost entirely into thermal energy, which is transferred as heat to the environment.

7. Using Energy in the Body: Energy Outputs

8. Using Energy in the Body: Energy Outputs

9. Efficiency of the Human Body
As you climb stairs, you change your potential energy. If you climb 2.7 m and your mass is 68 kg then your potential energy is
On average, you use 7200 J to climb the stairs.

10. Efficiency of the Human Body
We compute the efficiency of climbing the stairs:
We typically consider the body’s efficiency to be 25%.