HEALTH PROMOTION

HOW TO ESTIMATE AEROBIC CAPACITY FOR RECOMMENDING EXERCISE

For at least four decades researchers have been developing protocols for predicting maximal aerobic capacity (VO2

max). One

of the most notable protocols is the exer- cise cycle test using the Astrand-Ryhming nomogram which was developed in 1954. This protocol and many that have fol- lowed are based either upon heart rate response and/or a distance/time perfor- mance score in relation to a predeter- mined bout of exercise (eg.cycle ergome- try, walking, running, step-ups).

Protocols for predicting and estimating aerobic capacity which do not require spe- cial equipment include: ● The Astrand submaximal cycle test ● The Rockport 1-mile walk test ● Cooper’s 12-minute run field test ● The McArdle step test ● The Keele Lifestyle nomogram for pre- dicting VO2 exertion

max from ratings of perceived

It is paramount that a general resting health screening assessment/medical his- tory or medical examination is performed prior to carrying out any exercise tests.

perceived exertion There are some instances where predicting VO2

The Keele Lifestyle nomogram for predicting VO2

max from ratings of max using heart rate, such as in the

Astrand test, is neither possible nor valid, including: ● Testing an older individual who may feel that they are working hard, yet their heart rate does not rise above 120 bpm, which makes using the Astrand and McArdle step test protocols invalid ● Testing an individual who has an atyp- ically fast or erratic pulse rate from either a previously known condition or due to environmental or emotional factors ● Testing an individual who is on medica- tion (eg.beta blockers) that either slows down or speeds up the heart rate, which alters the typical response to exercise

The Keele Lifestyle nomogram follows exactly the same protocol as the Astrand test except that instead of measuring

6 No exertion at all

7 Extremely light 8 9 Very light 10 11 Light 12 13 Somewhat hard 14 15 Hard 16 17 Very hard 18 19 Extremely hard 20 Maximal exertion

Table 1: Borg’s 15-point RPE Scale

The reason the scale goes from 6-20 instead of 1-15 is that if the RPE value is multiplied by 10, this would predict the heart rate at that intensity. For example, an RPE of 6, equating to sitting still (no exertion) represents a heart rate of 60, which is the average resting heart rate of

Main points for correct usage of RPE

1 2

A standardised set of instructions in following points 2-5 below

The RPE scale should be seen clearly and be in full view of the exerciser –

Table 2: Recommended suitable pedal speeds and workrates for sedentary or age 50+ people are:

Pedal speed Workrate (rpm)

Men Women 60 50-60

(watts) 30-50

25-30 SportEX 25

heart rate, it is the rate of perceived exer- tion (RPE) which is important. RPE should never exceed a value of 15 at any time during the test.

Using rate of perceived exertion The RPE test has become an accepted tool in sport and exercise science with its use ranging from exercise testing, monitoring and prescription, to the training of elite athletes and the rehabilitation of car- diopulmonary patients.

a middle-aged man. At the other end of the scale, an RPE of 18-20 (maximal exer- tion) equates to an average maximal heart rate of 180-200 for a middle-aged man, remembering that maximal heart rate is estimated by 220 minus age.

It is worth noting that due to the scepti- cism of people not believing that a sub- jective rating scale can be a valid tool for measuring exercise intensity, a mountain of research has accumulated to test this validity. The key to ensuring validity is the correct use of the RPE procedure.