Why Are the First Symptoms of Hypoglycemia So Important?

Hypoglycemia is when blood sugar levels are below 4.0 mmol/L. This is the most frequent and unpleasant side effect of insulin, which is required to treat type 1 diabetes (T1D). Hypoglycemia can have many serious consequences, and can lead to falls and discomfort, or even the loss of your driver’s licence.     

Understanding how your body responds to hypoglycemia

A normally functioning pancreas maintains blood sugar levels in range by producing insulin as needed to decrease blood sugar. It can also produce a hormone called glucagon, which has the reverse role of insulin and increases blood sugar.

When you have T1D, your pancreas no longer produces insulin and secretes less glucagon. This makes you at a high risk of hypoglycemia because you have to administer insulin and don’t have enough glucagon to offset low blood sugar levels.  

Another hormone, called adrenaline, will send warning signals (e.g., sweating, shakiness, headache) to allow the person to treat their hypoglycemia before it turns severe. When the brain is lacking its main source of energy—glucose, or sugar—a person is experiencing severe hypoglycemia and might not be able to treat it on their own. Severe hypoglycemia may also lead to loss of consciousness and seizures.  

Do symptoms of hypoglycemia evolve over time?

Over time, your body may get used to hypoglycemic episodes, and you may no longer feel or recognize any of the symptoms. When this happens, the first warning signals get triggered at a gradually lower blood sugar threshold, until they eventually disappear. It is estimated that about 25% to 30% of people with T1D experience significantly decreased symptoms of hypoglycemia. 

If your blood sugar levels are regularly high, you may feel symptoms of hypoglycemia when your blood sugar levels drop quickly, even if they don’t go below 4.0 mmol/L. 

What can I do to feel symptoms of hypoglycemia again? 

If you no longer feel symptoms of hypoglycemia or don’t feel them as intensely as you used to, you must be particularly careful to avoid hypoglycemic episodes as much as you can. Hypoglycemic episodes should not represent more than 4% (one hour or less) of your day. This goal is still valid if your glycated hemoglobin (HbA1c) is within target (i.e., under 7%). 

Here are a few tips to reduce (or, ideally, eliminate) hypoglycemia and regain awareness of your symptoms.

  • Temporarily increase your target blood sugar levels. For instance, you could aim for a range between 5.0 and 11.0 mmol/L (as opposed to the usual target, 4.0–10.0 mmol/L) and maintain it for at least two months.
  • Regularly adjust your insulin doses. For instance, you could lower your nighttime basal rate to avoid hypoglycemia.
  • Assess and minimize situations associated with the risk of hypoglycemia. For instance:
  • Reassess your correction factor, which allows you to calculate how much insulin to inject to correct hyperglycemia, to avoid taking too much insulin.
  • Identify any areas with lipodystrophy and avoid using them as injection sites. 
  • See whether you need a refresher on counting carbs to calculate your mealtime insulin doses more accurately.
  • Explore your options. Long-acting types of basal insulin (e.g., Tresiba, Toujeo, Lantus, Basaglar) carry a lower risk of hypoglycemia than intermediate-acting types of insulin (e.g., NPH, Humulin N).

Several studies have shown that these strategies combined with regular check-ups with a healthcare team are successful in reducing the risk of severe hypoglycemia and regaining some symptoms of hypoglycemia.

Using technology to spend less time in hypoglycemia 

Technological advances in the treatment of diabetes can help to prevent and reduce hypoglycemia. 

For instance, an alarm can be set on some continuous glucose monitoring (CGM) systems to warn the user that blood sugar levels are getting close to a predefined threshold. This allows patients who no longer feel any symptoms to ingest fast-acting carbs (sugar) before their blood sugar levels drop too low. Some healthcare professionals recommend increasing the alarm threshold (e.g., from 4.0 mmol/L to 4.5 mmol/L) to reduce time spent in hypoglycemia.

Some CGMs also feature trend arrows that show the blood sugar curve in real time, which can help to anticipate, and often, prevent hypoglycemia.  

Insulin pumps also have interesting features such as adjustable basal rates when doing physical activity or when a hypoglycemic episode is looming. The most recent models, also called “artificial pancreases,” have software that adjusts insulin doses automatically based on the user’s CGM readings, which helps to significantly reduce the risk of hypoglycemia.

Other options to regain hypoglycemia awareness 

Other methods have proven successful in regaining hypoglycemia awareness, such as psychoeducation and physical activity programs that are under study. 

A study from the Montreal Clinical Research Institute (IRCM) is currently running a trial with a high-intensity exercise program combined with a training program (FEEL-HIIT) to help patients to regain some symptoms of hypoglycemia. There is currently a call for participants in the Montreal area, and long-distance participants from across Quebec will be accepted in early 2022. To learn more or sign up, click here»

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  • Farrell, C. M. & McCrimmon, R. J. (2021). Clinical approaches to treat impaired awareness of hypoglycaemia. Therapeutic Advances in Endocrinology and Metabolism, 12, 1–11. https://doi.org/10.1177/20420188211000248  

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