EXERCISE INTENSITY

Physical activity is good for us and can do wonders for diabetes management, but what sort of exercise and how much do we need to do to get all these benefits? MARIAN BRENNAN writes.

Physical activity guidelines in Australia encourage us to engage in 150-300 minutes per week of moderate intensity activity or (for those aged between 18-64 years) 75-150 minutes per week of vigorous intensity activity, and to include muscle strengthening activity on at least two days per week. But what is ‘moderate’ or ‘vigorous’ intensity exactly? What does it look like, and will it look the same for everyone?

Intensity is just a gauge of our heart and breathing response to activity. We know that for those aged between 18-64 there are some great benefits to activity done at vigorous intensity, if it is right for us and we enjoy it! But as you will start to see, the right type of activity for one person may not be the same intensity for the next person, even if it is done at the same pace, distance, and duration. It is quite possible that running, for example, might be moderate for one person and vigorous for someone else. For this reason, it can be more useful to refrain from thinking about a certain type of activity (running, walking, cycling, swimming) as having a set intensity because this is likely to be different for everyone, depending on how accustomed they are to that activity. Instead, we can gauge the intensity of an activity (for you) by using one of these three different measures:

 Talk test: Can you speak comfortably?

 Rate of perceived exertion (RPE) scale: A scale from 0-10, where zero is you at rest and 10 is 100% exertion where you can’t go any harder and need to stop

 Heart rate: Working at a certain percentage of your maximum heart rate (max heart rate = 220 – your age)

So, for example if I (50 years of age) were walking with my friend Bob (60 years of age) and I was chatting away to Bob, was a little bit breathless, but couldn’t sing to him, or I rated exertion to be a 3-4 out of 10, or my heart rate was between 93 – 117 beats per minute, I would be exercising at a moderate intensity. Bob, on the other hand starts to break out in song and is singing to me, he rates his exertion to be 1-2 out of 10, and his heart rate was 64 – 86 beats per minute. Although we are doing exactly the same activity, Bob is working at a light intensity.

How To Gauge Intensity

Adapted et al. J Sci Med Sport 2009 activity can be a good way to get more ‘bang for your buck’. On the other hand, moderate intensity activity, done over longer periods has been shown to be more effective in achieving sustained weight loss as our bodies are better able to utilise fat as a fuel source at these intensities.

Although the benefits of physical activity are vast, some specific benefits require us to do a bit more than others. For example, we can enjoy benefits to our heart, blood vessels, blood glucose levels, mental health and well-being by engaging in 150-minutes of moderate intensity activity or 75-minutes of vigorous intensity activity. If you want to increase your activity to reduce weight or reduce your risk of some cancers, we need to do a bit more, closer to the 300-minutes per week of moderate or 150-minutes per week of vigorous intensity activity. As you can see, by working at a vigorous intensity, we can get the same benefits of moderate intensity activity by doing half as much. So, if time was a barrier for you, including some vigorous intensity

The good news is you don’t need to commit to any one type of intensity! Simply adding in small bouts of vigorous activity amid your moderate intensity activity can maximise those benefits and make things a bit more interesting. For example, try walking at a faster pace or up a hill for 30 second bouts a few times during your moderate intensity walk.

If you have never tried vigorous intensity activity and are living with diabetes, it is worth having a conversation with your GP and or exercise physiologist to make sure it is right for you. If you are new to exercise or haven’t done anything for a while, we would suggest starting with moderate intensity activity for a duration that you are comfortable with and progressing slowly towards the above-mentioned recommendations.