The signs of high and low blood sugar

Blood sugar is a measure of the amount of sugar or glucose in your blood. This sugar comes from the food you eat and is the body’s main source of energy. While a sufficient blood sugar level is necessary for the body to function, a level that is too high can cause serious harm to the body. That’s why it is important for your health to keep your blood sugar within a healthy range. A blood sugar level that is too high is referred to as diabetes. It can occur when your body does not produce insulin (Type 1 diabetes), or because your body does not produce or use insulin effectively (Type 2 diabetes). Although diabetes is a common condition, the symptoms of high or low blood sugar are often difficult to recognize or may be mistaken for other health problems. For this reason, an estimated 36% of adults in Europe have diabetes without knowing it (IDF, 2021). The ability to recognize the signs of abnormal blood sugar levels can help prevent Type 2 diabetes before it occurs or help people with diabetes keep their blood sugar in a healthy range. Read on to learn more about the signs of high and low blood sugar.

Table of Contents

• Measuring blood sugar
• Symptoms of high blood sugar
• Symptoms of low blood sugar
• How to regulate blood sugar

Measuring blood sugar

Blood sugar levels can be diagnosed and monitored in a variety of ways. People with diabetes can measure their blood sugar several times a day using a finger-prick test or a continuous glucose monitor such as the Freestyle Libre (CDC, 2021). Checking your blood sugar throughout the day can help you understand how your body responds to certain foods and how much medication you may need. The following values are used to diagnose diabetes:

If you have been diagnosed with diabetes, it is generally recommended to keep your fasting blood sugar between 4.5 and 8 mmol/L. A good post-meal blood sugar value (~2 hours after eating) is below 9. Therefore, when managing diabetes, you should aim to keep your blood sugar between 4.5 and 9 mmol/L (Thuisarts, 2022).

HbA1C

A hemoglobin A1C test (HbA1C) measures your average blood sugar level over the past 2-3 months. This test can be used to diagnose diabetes or check whether your diabetes is under control. The following values are used to diagnose diabetes:

If you have been diagnosed with diabetes, it is generally recommended to keep your HbA1C level below 7% (Tello, 2020). This target may vary and should be discussed with your healthcare provider. For more information, read our blog “What is HbA1C?” It is now also possible to check your HbA1C level at home using a self-test, such as the Homed-IQ Blood Sugar Test or the Homed-IQ Heart Health Test. These tests allow users to check whether their diabetes may be undiagnosed or how well they are managing their diabetes without needing to visit a doctor. If you would like to learn more about the differences between an at-home HbA1C test and a doctor’s test, read our blog “Diabetes testing – should you do a home test or see a doctor?”

Symptoms of high blood sugar

High blood sugar (hyperglycemia) occurs when the level of glucose in the blood is too high. High blood sugar is the main symptom of Type 1 and Type 2 diabetes, but it can also occur in people who have certain chronic diseases, are stressed, or are ill. Lack of physical activity, insufficient insulin intake (in diabetics), overeating, dehydration, unhealthy diet, and irregular meals can all cause high blood sugar (NHS, 2022).

The symptoms of high blood sugar are usually subtle at first and only appear when levels become very high. The symptoms of high blood sugar are the same as the symptoms of untreated diabetes, which leads to high blood sugar due to a lack of insulin. Symptoms may include:

• Extreme thirst

• Frequent urination

• Weight loss

• Blurred vision

• Fatigue

• Recurrent infections such as thrush, bladder infections, and skin infections

A very high blood sugar level can lead to life-threatening complications such as diabetic ketoacidosis (DKA). Ketones are a chemical substance produced by the liver when it breaks down fat. Your body uses ketones during fasting, prolonged exercise, and when few carbohydrates are available. If your body does not have enough insulin, it starts turning fat into energy instead of using blood sugar. This process creates ketones, which accumulate in the blood and can lead to DKA. This is a medical emergency and must be treated immediately (NHS, 2022).

Symptoms of DKA include:

• Fruity-smelling breath

• Thirst

• Fainting

• Feeling unwell

• Frequent urination

• Confusion

• Coma

Symptoms of low blood sugar

Low blood sugar is defined as a blood glucose level below 3.5 mmol/L (CDC, 2021). Hypoglycemia most commonly occurs in people with Type 1 diabetes and can be caused by too much insulin, too few carbohydrates for insulin uptake, changes in daily routine, hot weather, or alcohol consumption.

The symptoms of low blood sugar vary from person to person. For diabetics, it is important to recognize their own signs of hypoglycemia. Symptoms may include:

• Hunger

• Dizziness

• Rapid heartbeat

• Nervousness

• Shaking

• Sweating

• Irritability or confusion

Some people do not experience symptoms of low blood sugar until levels become dangerously low. This is known as hypoglycemia unawareness and can occur in people who have had diabetes for a long time, frequently have low blood sugar, or take certain medications (CDC, 2021). People who are unaware of their hypoglycemia may need to monitor their blood sugar more frequently.

How to regulate blood sugar

Stabilizing blood sugar levels is beneficial for both people with and without diabetes. A healthy diet, maintaining a healthy weight, and regular exercise are very important for keeping blood sugar levels in check (CDC, 2021). Additionally, the following tips can help maintain stable blood sugar:

• Eat regularly and do not skip meals

• Limit alcohol and sweets

• Drink water instead of juice or soda

• Watch your portion sizes

• Track your blood sugar and be aware of what causes it to rise or fall (for diabetics)