Our body releases energy during respiration. Respiration is a chemical reaction that uses oxygen from breathing and glucose from food. The products of this chemical reaction are carbon dioxide and water and our body lets them out. This is the chemical equation of respiration:
glucose + oxygen carbon dioxide + water (+energy)
Respiration that uses oxygen is called aerobic, but it can also take place without oxygen, in which case it is called anaerobic. You can tell when your body goes into anaerobic respiration during intensive exercise, because your muscles ache from the production of lactic acid the next day.
It is really important for our health and longevity that we maintain a healthy lifestyle and do as much exercise as possible. Exercise combined with a balanced diet and no smoking or excessive alcohol ensures our blood pressure remains normal, and we lower the probability of getting a disease or illness. Normal blood pressure levels for an adult are 110-125 mmHg for the systolic pressure (the maximum pressure our heart produces) and 60-70 for the diastolic pressure (the blood pressure between heart beats).
A balanced diet consists of all types of food but less salt, sugar and fat. The pyramid below shows the different types of food and how much we should be eating. Study it carefully because many questions will be based on it.
Red meat, chicken, fish, as well as pulses (beans, lentils, chick peas) provide protein necessary for growth and repair. Rice, bread and pasta proide carbohydrates for energy. Fruit and vegetable provide vitamins and minerals. It is worth noting the importance of fibre in cereals, fruit and vegetable, necessary for a healthy digestive system and water, which makes up most of our body.