The Open Door Web Site
Part XVIII: Energy and Activity : Feeding, Breathing and Activity Index
ENERGY AND ACTIVITY
Respiration and Activity
Respiration is a process which takes place in all living organisms. It is the process which releases energy from food. Respiration is like combustion; it needs oxygen if it is to work efficiently.
We breathe oxygen in through our mouths and down to the lungs. Other animals have different breathing systems; for example, a fish has gills, and plants take in gases through their leaves and roots. In our body the oxygen travels from the lungs all over the body in the blood stream.
The amount of oxygen an animal needs will be very large if the animal is very active. This is because if the animal is active it needs a lot of energy. To get that energy from its food it needs a lot of oxygen too. Two examples which show this are in the opposite column.
It is interesting to see that when the bird is flying slowly, such as when it is taking off or landing, it uses more oxygen than when it is flying at 35 km per hour.
Note: The World Health Authority says that 12600 kJ per day is just adequate for an adult man.
If we do not get enough energy from our food we may use some of our energy reserves. Our body stores most of its energy as fat. If we do not eat enough energy-giving food over a long period of time (months or even years) we will lose our reserves and our health will start to suffer. Today about 400 million people in the world do not get enough energy in their diet. (The total world population is over 6000 million people). This is hunger and it is thought that 12000 people die each day because they do not get enough to eat.
The opposite situation is also bad for our health. If we eat too much energy-giving food we store the excess energy that we do not use. This energy is stored as fat. This means that the person increases in mass and the blood vessels can become blocked with a fat called cholesterol. This can lead to poor health, especially diseases of the heart. Therefore to be healthy you need a balanced diet which does not contain too much energy or too little.
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