Getting tired

We can get tired physically, but also in our “mind” for example after a whole day of school. To undertake activities such as running very fast, or just cycling to school and to think carefully, we need energy. The body gets this energy from our diet.

Energy supply

We don’t know exactly why we get tired, but most probably this has to do with the energy supply of our body. When we are tired we rest or go to sleep. The idea is that when we sleep, on the one hand we save energy, and on the other we rebuild energy and repair any damage to cells.

Sleeping and resting

So we don’t know yet how tired we are, but we do know that sleeping and resting are very important. A scientific study has found that rats that are kept awake for days eventually die. It is to be expected that this is also the case in humans, but it is better not to try that ….

It is therefore best to simply go to sleep on time to give your body the necessary rest.

How much energy do you need for a whole day?

To be active all day, our body needs energy. This energy is expressed in kilocalories (kcal). How much energy you need for a whole day is different for everyone. It depends on what you have eaten and how much energy you have already consumed.


You can compare energy in your body with petrol in a car. How much gasoline is needed for a day depends on how much you have refueled, and how hard and far you have driven. The energy you need differs per activity. For example, an hour of cycling takes more than 200 kcal, and to solve maths at school you need about 100 kcal. Even while sleeping you use energy, up to 50 kcal per hour.


The energy we need comes from our diet. The main nutrients from which we obtain energy are carbohydrates. Think of sugars and starch. For example, one gram of carbohydrates provides 4 kcal. Fats also give us energy. For example, there is 9 kcal in one gram of fat.


With a healthy diet you ensure that there is a balance between what you get in energy and what you use in energy. When you consume more energy than you body needs, you become fatter. If you use more energy than you absorb, you lose weight. It is therefore important that you find a good balance in eating and exercising.