Glucose Variability - ExCarbs


Variability  = Frustration

but here are some reasons why 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.

The 8 most common reasons for Glucose Variability

Body Temperature
Injection Site
Time After Eating
Muscle Groups Used in Exercise
Exercise Regime
Previous Exercise Regime
Previous Low
Caught in the Moment

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.

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.

  • Injected insulin with a meal is designed to work best after about 2 hours.
  • If your exercise happens roughly 2 hours after you consume food insulin, then the risk of your blood sugar dropping is much more than if you exercise 3-4 hours after eating when that insulin is wearing off.

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.

  • Aerobic and anaerobic exercise use different pathways to use energy, so combining these two types may be helpful.
  • If you do anaerobic exercise first (e.g., squats, weights) followed by aerobic, the blood sugar tends to stay more stable or go up slightly after exercising.
  • If you do aerobic exercise first (e.g., running, swimming, dancing) followed by anaerobic, then blood sugars tend to trend down following exercise.

See “What is Exercise”

Doing a bout of exercise in the morning can leave 2 things to think about later in the day:

  • The body may not have had the chance to build up its energy stores for later in the day making low blood glucose more likely. And…
  • The body’s response to low sugar isn’t as sharp as it usually is after a bout of exercise so you may not get quite as good warning signs.

*So, be aware that being active in the afternoon after exercise in the morning may make things slightly more difficult to manage.

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.

  • 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.

*Often this can cause the blood sugar to go up and extra insulin may be needed to bring it back down.