We need food, water and energy to survive because we will starve without food, we will die of thirst, and we will fall asleep without energy.
If we exert ourselves, what are three (or more) signs that our bodies are in distress? Why?
We breathe heavy because we need air, our faces get red because our hearts pump more blood, and our muscles get sore because we were using them.
What can we do to make these signs go away?
We can stop exerting ourselves and drink fluids.