Skip to content

Glucose Variability

Your blood sugars can be unpredictable.

In other words, why is it that doing the same activity at the same time, after the same breakfast, can sometimes be managed perfectly and sometimes be a nightmare? This is called glucose variability.1

Variability = Frustration1,2

Not everyone with diabetes is able to keep their blood sugar levels within a reasonable range.
As anyone who struggles with this condition knows, blood sugar levels that go up and down cause symptoms that can be severe enough to interfere with daily life. Efforts to control these unpredictable sugar swings and the symptoms they cause can be a source of frustration that only gets worse if you are made to feel responsible.

However, there is a number of reasons why this happens, apart from things you can control!1,3

1. Glucagon
A not very well-known fact is that the concentrations of the hormone glucagon are disturbed and contribute to the peaks and troughs in the levels of blood sugar.

2. Body Temperature
It is well known that in warm temperatures when the body is trying to cool down and the blood flows nearer to the skin surface any insulin injected will be absorbed quicker and will seem to work much better. The opposite is also true.

3. Injection Site
Try injecting at a site away from the muscles that are going to be used. For example, if you are cycling, try injecting into your stomach rather than thighs.

4. Muscle Groups Used in Exercise
The rate your body will use up the sugar in your blood will depend also on the number and size of the muscles being used.

5. Previous Low
Having had a period of low blood sugar, the body doesn’t respond to further low blood sugars quite as well and the signs of the blood sugar dropping may disappear. If this is combined with exercise it can make the exercise quite difficult to manage. If a hypoglycemic event in the previous 24 hours was quite profound then exercise should be postponed until the following day. There is a real risk of a further bad hypoglycemic event with much reduced warning signs.

6. Caught in the Moment
Excitement and stress can cause the blood sugar to rise quite dramatically.
If your sport or exercise suddenly becomes competitive and extra excitement is added such as an important match or competition, those extra stressors may change the way your blood sugar behaves.

References: 1. Glucose Variability – ExCarbs [Internet]. ExCarbs. 2018 [cited 12 October 2020]. Available from: 2. Trouble Controlling Your Blood Sugar? It Could Be ‘Brittle Diabetes’ [Internet]. Health Essentials from Cleveland Clinic. 2019 [cited 12 October 2020]. Available from: 3. The cause of fluctuating blood sugar levels in diabetics | Knut and Alice Wallenberg Foundation [Internet]. Knut and Alice Wallenberg Foundation. 2013 [cited 12 October 2020]. Available from:

Back To Top