Good lung function is important for optimum health related fitness.  Being able to breathe easily makes everyday tasks feel so much less arduous.

Spirometry (Lung function tests) are breathing tests that provide the clinician with a detailed assessment of how well your lungs are working. This method of testing is a useful for detecting early changes in occupationally acquired disease. When performed correctly, it can be used to assess the progression of occupational lung diseases as well as provide an overall assessment of a workers lung health.

The test is designed to measure four factors regarding expiratory lung function tests as follows:

Forced Vital Capacity (FVC)

Forced Vital Capacity (FVC) or lung volume is the total amount of air that an individual can breathe out after completely filling their lungs, and is measured in litres (l).

Lung volume usually depends on the individual's age, sex and height - being largest at around twenty to twenty-five years.  Males normally have bigger lungs than females, and taller people generally have larger lungs than shorter people.

There are many reasons for Forced Vital Capacity (FVC) to be lower than normal. For example, bronchitis, emphysema, asthma and other lung disorders will affect lung volume.  Smoking is a serious cause of lung damage.  Being overweight can often reduce lung volume, since the diaphragm has little room to move downwards and excess fat on the chest wall restricts expansion of the lungs.  Poor physical condition can lead to weak respiratory muscles and poorly developed lungs.  Also, low Forced Vital Capacity (FVC) values have been identified as a risk factor in heart disease, so steps should be taken to try and improve this.

Forced Expiratory Volume (FEV1)

Forced Expiratory Volume (FEV1) or lung strength is measured by how much air an individual can forcibly expel in one second in litres (l). This depends on a number of factors, such as clear airway tubes and 'clean' air sacs (alveoli), which are found at the end of the tubes inside the lungs.  If all the alveoli were taken out and laid on the ground, these air sacs would cover the size of a tennis court! Lung strength also depends upon strong respiratory muscles - the intercostal muscles of the chest and the muscles of the back, sides, stomach and neck.  Forced Expiratory Volume (FEV1) values are most certainly affected by smoking, and by the other lung disorders mentioned above.

Forced Expiratory Ratio (FER)

Forced Expiratory Ratio (FER) or lung efficiency is a measure of the percentage (%) of maximum lung volume that can be expelled in one second.  Again, this depends on clear airway tubes and efficient alveoli.  This measurement gives a useful index on lung function.

Peak Expiratory Flow Rate (PEFR)

Peak Expiratory Flow Rate (PEFR) is the measure of the maximum speed or flow rate, that an individual can generate during a forced exhalation, and requires a combination of lung strength and lung power, together with clear and efficient respiratory passages. Peak Expiratory Flow Rate (PEFR) is measured in litres per minute (l/min).

Regular aerobic exercise, keeping body weight under control and not smoking, will help to improve an individual's lung function. Swimming in particular, is an excellent form of lung exercise.

If an individual's lung function is found to be substantially low, they are advised to have this checked out by their General Practitioner.  A series of remedial exercises, together with medical treatment may be necessary.

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