You must have drawn the conclusion that exercising can help you to lose those unwanted pounds and tighten up your wobbly bits.

But how does it work?

All depends on metabolism. Why? The answer is simple. Because metabolism is the process by which your body makes use of the food you eat in order to provide the necessary quantity of energy to your body.

There are three ways to spend your energy daily: basic needs, food processing and physical activity.

Not only an activity can burn calories, but also the moments when your body is passive, at rest. Even then there exist biochemical processes occurring that require energy to drive them.

Calorie metabolism provides the energy for basic bodily needs such as breathing, blood circulation and cellular growth and repair.

The most intense process of your body is food digestion. The digestive processes are maintained with almost ten percent of the calories you eat each day.

More than that, the last but not least, the daily physical activities, such as running, swimming or walking, also require calories.

Unlike the basic, digestive needs of your body, the physical activity you do depends only on your choices. If you want to burn more calories and lose weight, you need to exercise hard.

The amount of calories you burn while exercising depends on your age, sex and body composition.

Older people tend to have a slower metabolism and also less muscle , which is one of the most "active" calorie-burning tissues.

Women burn less calories than men when performing equivalent exercise, also because men tend to have more muscle mass.

People with bigger weight can burn calories at a higher rate than smaller people, because their bodies require more energy for movements.

Let's take for example a person with a weight of 130 pounds, racing a bicycle at more than 20 miles/hour would burn 944 calories an hour.

For the same amount of exercise, a person who has a weight of 155 pounds would burn 1125 calories/hour.

The number of calories you burn is also influenced by the intensity with which you exercise – in general the harder the exercise, the more calories burnt.

Running at 5mph burns 472 calories per hour, whereas at 11mph you can burn 1062 calories per hour.

High impact aerobics also burns more calories than a lower impact workout (413 calories versus 295 calories/hour).

It is said that sports that require intermittent running, such as:

basketball (472 calories/hour), tennis (472 calories/hour), football (531 calories/hour), soccer (590 calories/hour)

give you the ability to burn more calories than less active sports such as:

golf (236 calories/hour), cricket (295 calories/hour).

Never try to find excuses for not doing housework, because the household chores are a good way to lose some calories fast and easy, without even thinking about them:

Cleaning your house will burn 207 calories/hour, while carrying heavy loads around the garden can burn up to 472 calories/hour. Painting or plastering your home burns about 266 calories/hour; also scrubbing a dirty floor will make you lose calories - about 325 calories/hour.

Only 30 minutes spent on engaging in physical activity each day, can help you burn calories, beat the battle of the bulge and gain fitness.

Go for it!