Exercise Intensity


Exercise Intensity

This is the amount of effort required to perform a certain type of exercise. There are many ways to assess exercise intensity from the simple (the Talk Test) to the scientific (calculating VO2 max)



Talk Test

In simple terms how easy is it to talk during exercise?

Light intensity means you would be able to carry out a normal conversation or even sing during exercise

Moderate intensity means you are able to talk during exercise but would struggle with a full conversation. You would not be able to sing

Vigorous intensity means being unable to say more than a few words



Resting Heart Rate

Here you need to check your heart rate first thing in the morning or in the evening whilst sitting down resting and without having consumed alcohol or caffeine.


We recommend checking your heart rate at the wrist. You should be able to feel the radial artery at the wrist below the base of your thumb. Place the tips of your index and middle fingers (not your thumb) over the artery and press lightly. Take a full 60 seconds (timed using a watch) to count the heart beats. For an otherwise healthy 50 year old the rate should be somewhere between 60 and 100 beats per minute.


Light intensity means increasing your heart rate 30% above the resting value

Moderate intensity means increasing your heart rate 60% above the resting value

Vigorous intensity means increasing your heart arte 90% above the resting value



The Borg Rating Scale of Perceived Exertion

The Borg Rating Scale of Perceived Exertion is a questionnaire which you can ask yourself. It asks you to rate how hard the exercise is. It is rated between 6 and 20 as in the table below. You are looking to rate the exercise in the 12 to 16 range for moderate intensity.




VO2 max

This is the maximum capacity of the body to use oxygen  and provides an assessment of physical fitness. It is expressed either as the rate in litres of oxygen being used per minute (l/min) or as a relative rate of millilitres of oxygen per kilogram of bodyweight each minute (ml/kg/min).


To calculate exercise intensity work out the maximal heart rate target which = 220 minus your age (in years)

For a 40 year old

Maximal Heart Rate is 220-40 = 180 beats per minute

Moderate Intensity exercise is 50% (range 40-60%) of VO2 max and the heart rate rise required to achieve this is 50-70% of the maximal heart rate.

So, for a 40 year old to achieve Moderate Intensity Exercise

Max Heart Rate = 180

50-70% of Max Heart Rate = 90-126 beats per minute

Obviously this depends a bit on the resting heart rate (the slower the resting heart rate the slower will be the heart rate at moderate intensity)