If an individual has decided to start exercising, she needs to know how fit – or unfit – she is in order to choose the right level of activity. The best advice is for an individual to consult her doctor, who will carry out general health tests to ensure that it is safe for her to embark on an exercise regime. If she simply wants to discover how fit she is, she could visit a sports centre; well-equipped gyms may be able to run tests to determine an individual’s body. There are also some simple tests that can be carried out at home.
Tests to determine general health, body composition, body type, cardio-respiratory fitness, muscular strength andare all common and useful aids that Western doctors and sports trainers use to gauge body fitness. Practitioners of Eastern medicine take a different approach to assessing the body, and tend to concentrate on the flow of energy around the body to measure health and wellbeing.
A consultation with a doctor for pre-exercise health tests and advice on suitable types of exercise is essential if an individual is in one of the following groups: she has a sedentary lifestyle or has not exercised for a number of years; she is overweight; the person is a woman over 50 (or a man over 40) and suspects she (or he) may be unfit; she is pregnant; she has an existing illness or a history of heart disease; or she has undiagnosed problems such as chest pains or breathlessness.
The doctor will probably ask questions about an individual’s health, test blood pressure and cholesterol levels, and if there is a possibility of heart disease, she will carry out tests to monitor the heart during exercise. Based on the consultation and test results, the doctor can recommend exercise of an appropriate intensity to improve body fitness.
Using weighing scales is a somewhat old-fashioned way of telling whether an individual is above the ideal weight for her height. Scales can be misleading because muscle weighs more than fat. Some people take up exercise and are disconcerted to find that they actually put on weight – this is because fat is replaced by heavier muscle.
Body mass index
A simple way of assessing body composition is to calculate body mass index (BMI). This is done by dividing weight in kilograms by the square of height in metres. If a person is 1.65m tall and weighs 64kg then she has a BMI of 23.5: 64 divided by (1.65 x 1.65). A BMI of 20-25 is desirable; 26-8 will lead to increased health risks; and above 29 is obese. Although calculating BMI is not recommended by some health experts because of disagreement about acceptable levels, this is one of the few health assessments that can be carried out at home.
The best way to assess body composition is to measure how much fat there is on an individual. Even a ‘thin’ person can carry a lot of fat if she does not exercise. Women carry more fat than men, the optimal amount being 19-22 per cent, dropping to 14 per cent for female athletes. Men carry an optimal amount of 11-17 percent fat; less if they train regularly. Male bodybuilders may carry as little as 6 per cent fat.
A common way of estimating body fat is by using skinfold callipers to measure subcutaneous fat (fat stored under the skin). Like a large pair of tweezers, callipers gauge the thickness in millimetres of fat stores under the skin. Measurements are usually taken on the front and back of the arm, on the waist and on the back. Ideally, the measurements should be taken by a person who is experienced in this technique so that readings are accurate and consistent. An individual can attempt to make a rough estimate by just pinching the skin with the thumb and forefinger. If the fold of skin pinched is greater than 25mm (1in) she may need to lose weight through a combination of dietary changes and exercise.
Body composition can also be estimated by connecting an individual to a machine that measures bioelectric impedance (the speed at which a low electrical current flows through the body). Since fat is a poor conductor of electricity, the more fat an individual is carrying, the slower the flow of electricity. Using this technique, an expert can assess the thickness of muscle and fat at various sites around the body, and estimate total body fat. This test is available at some sports centres.
A less common way of assessing body composition is a laboratory test that employs under-water weighing. The individual undresses and is weighed both in air and under water (adjustments are made to account for air in the lungs and gas in the gastrointestinal tract). Fat is less dense than muscle or bone so it is possible to calculate the percentage of body fat. The higher the percentage of body fat, the easier it is for the body to float. This technique has to be repeated several times before a calculation can be made. The disadvantages of this test are that it is not readily available and may be subject to errors in calculation.