Measuring Your Own Fitness

Measuring your own fitness

There are a number of benefits from being able to measure your own fitness:

• It can give you an idea of how fit – or unfit – you are in comparison with others of your own sex and age. You should be concerned if you find that you are average or less – most people are far less fit than they should be. You should not be content with anything less than ‘above average’.
• Seeing just how unfit you are might (should) stimulate you to take up or increase exercise.
• It gives you a benchmark to measure future improvements and the effectiveness of whatever exercise you are taking.

The simplest rough indicator of physical fitness is your resting heart rate. For men any level above 70 and for women above 80 beats per minute may indicate reduced fitness. These levels work for large groups in identifying increased risk of cardiovascular disease and cancers, but are too blunt a weapon for the individual.

The Cooper Test

Maximum oxygen uptake or VO_2max  (see glossary if you cannot remember what this is) is the best measure of cardiorespiratory fitness. There are several ways in which you can estimate your own VO_2max accurately enough to be useful. The best of these is the Cooper test, devised by Dr Kenneth Cooper from the US in the 1960s.  Anyone with the ability to walk unaided can do it – and here is how.

The Cooper test measures how far you can travel on foot in 12 minutes when going flat out.  As simple as that, yet it gives a remarkably accurate indicator of VO_2max.  As you cover the distance, be aware of your limitations. Younger people and fitter older people can run for 12 minutes. If this is too hard for you, try a walk-jog, alternating fast walking with jogging. Older people and those who have not run for many years are best doing it at the fastest walk they can manage. Remember that 12 minutes of continuous exercise is longer than you might think. Don’t start too fast.

There are several ways of measuring the distance:

1. If you have a smart phone, download a Cooper test app and just follow the instructions. The phone will measure the distance covered in 12 minutes, work out your VO_2max and tell you how you did. The app will also tell you how you compare with others of your age and gender. Misleadingly, it gives the same comparisons for everyone over the age of 60, so does not do justice to older folk (see below for a broader age spread of normal values).
2. If you have a GPS watch, use it to measure how far you have gone in 12 minutes.
3. Use a measured track (you can make this yourself on any reasonable-sized playing field) and note the distance around the track you can cover in 12 minutes.

The following table, which is adapted from Dr Cooper’s findings, sets out the results from the distance covered in the 12 minutes, giving both your VO_2max and how you compare with everyone else of the same age and sex. Since Dr Cooper’s figures stop at the age of ‘over 60’, I have added my age predictions for 70–79-year-olds and 80–89-year-olds. However, these predictions apply only to those who are able to complete 12 minutes of walking and this may not be the case for many older people. For them, the 6-minute walk test is a much better measure of their fitness and how it compares to the population at large.

After you have completed the test, you can compare your results to the norms and recommendations for your age and gender with the table below.

12-minute run fitness-test results
Men

Age	Average (metres)	Average VO2max
20–29	2200–2399m	40.1
30–39	1900–2299m	35.6
40–49	1700–2099m	31.2
50–59	1600–1999m	28.9
60–69	1400–1700m	23.4
70–79	1300–1600m	21.1
80–89	1100–1400m	18.0

Women

Age	Average (metres)	Average VO2max
20–29	1800–2199m	33.4
30–39	1700–1999m	30.1
40–49	1500–1899m	26.7
50–59	1400–1699m	23.4
60–69	1300–1600m	21.1
70–79	1200–1500m	18.9
80–89	1100–1400m	17.8

To calculate your estimated VO_2max (in ml/kg/min) from the distance travelled in 12 minutes, use either of these formulas:

In miles: VO_2max = (35.97 x miles) – 11.29

In kilometres: VO_2max = (22.351 x km) – 11.288

The Rockport Walk Test

This is a one mile walk test which is suitable for those who do not wish to go at full tilt. It uses your weight, gender, time taken and heart rate at the finish of the test to calculate your VO_2max:

The test estimates your VO_2max using the following formula which incorporates body weight (kg), age (yr), gender (males = 1, females = 0), time to complete one mile (min), and postexercise heart rate (bpm): Please note that this test will not work for those who take medication which slows the heart rate (beta blockers and the like).

132.853 – 0.0769 x (Weight in kilograms) – 0.3877 x (Age) + 6.315 x (Gender – 1 for males, 0 for females) – 3.2649 x (Time in minutes) – 0.1565 x (Heart rate in beats per minute)

What a fiddle! Easier to go to a website which does it for you once you have entered your age, weight, time taken and heart rate at the end – like http://knightsofknee.com/calculators/FitnessTestCalc.htm

Six Minute Walk Test

For older, less fit people and those with heart or lung diseases, a 6-minute walk is often used and has also been shown to give an acceptable prediction of VO_2max. The procedure is much the same as the Cooper test but for 6 rather than 12 minutes and walking as fast as possible. Below is a table of expected results at different ages over 65. You will notice that the estimate of fitness given by this method is considerably lower than given by the Cooper test. This is probably because the samples of individuals used to calculate the figures were rather different. I believe that the Cooper test sample population was considerably fitter than the majority of older people and I find the 6-minute walk test results more convincing for this age group.

6-minute walk test results
Men

Age	Average (metres)	Average VO2max
65	596m	18.6
70	568m	18.0
75	534m	17.2
80	487m	16.3
85	427m	15.5
90	403m	14.2

 

Women

Age	Average (metres)	Average VO2max
65	535m	17.3
70	510m	16.7
75	482m	16.0
80	443m	15.1
85	406m	14.3
90	358m	13.1

 

There are a lot of formulae for converting distance covered in the 6-minute test into VO_2max but none is very accurate. Some involve body mass index (BMI) and can be very complicated to work out. The best is this:

VO_2max in ml/min/kg = 0.023 multiplied by the 6-minute walk distance in metres plus 4.95.

This works well for those whose maximum distance walked in 6 minutes is 600 metres or less, but underestimates VO_2max for those who can go further. For them, the Cooper test is more accurate.

What does the answer mean? Come back next week and I will tell you!