introduction | change of climate

The balancing act

Animal life began in the sea.

Inside the first cells, the liquid was probably like seawater. Even today, all living cells need the right amount of salt and water in them. Too much or too little and they die.

All animals must keep a proper balance of water and salt if they are to remain healthy.

Leaky skin

We humans lose water through our skin all the time. But when we get hot, we lose even more water through sweat in order to keep cool. We must drink enough to replace the lost water.

How else do we lose water?

We also lose some salt when we perspire. (How can you prove this?)

Not enough water?

Haemoglobin, the chemical that carries oxygen in our blood, will not work properly if we have the wrong concentration of salt in our cells.

If we have too little water and too high a concentration of salt, haemoglobin stops working and our body's cells start dying from lack of oxygen. Make sure you drink enough water when exercising!