A guide to BGLs and exercise

Discover the effects of your blood glucose levels and exercise

What should my BGLs be when I exercise?

< 4mmol/L:  A BGL less than 4mmol/L is usually referred to as hypoglycaemia. Exercise should be postponed until you have treated your hypoglycaemia. 

4mmol/L – 5mmol/L:  Have a small amount of carbohydrate. I.e. piece of fruit or small glass of milk before you start exercising. 

5mmol/L – 10mmol/L:  This is the ideal BGL range to exercise. Let’s get moving! 

10mmol/L – 14mmol/L:  Caution needs to be taken with BGLs consistently over 10mmol/L, consider gentle exercise and see your GP to discuss ongoing treatment. 

15mmol/L:  If your BGL is more than 15mmol/L postpone strenuous exercise. This is considered ‘hyperglycaemia’ and can cause BGLs to rise further and lead to dehydration. Exercising when BGLs are above 15mmol/L can also lead to the production of ketones for people with type 1 diabetes. 

Know the warning signs to stop exercising

While exercise is generally a safe activity, there are some warning signs to look out for. These signs let you know that you may have overdone it, or your body is having an abnormal reaction to exercise. 

If you experience any of the following during exercise, stop and rest. 

  • Chest, abdominal, neck, jaw or arm pain or tightness 
  • Palpitations, irregular or racing heart beat 
  • Feeling faint, light headed or dizzy 
  • Leg cramps or pain 
  • Symptoms of hypoglycaemia (stop immediately and treat!) 

If the pain/symptom does not go away within five minutes, seek urgent medical attention – dial 000. If the symptom subsides see your GP before starting exercise again. 

Remember to always discuss your exercise plans with your GP or an Accredited Exercise Physiologist especially if you have been inactive for a long time, have any medical conditions or injuries. 

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