If you have type 2 diabetes, your body gradually stops making enough
insulin and becomes less able to use the insulin it does make
effectively1. With too little insulin, your body cannot
absorb glucose from the food you eat and your blood sugar levels rise
and become harmful to your health2.
Understanding the connection between insulin, blood sugar and your
average blood sugar levels over time – also known as HbA1c
– is important for controlling type 2 diabetes3.
Why is HbA1c important?
HbA1c is a measure of your blood sugar levels over the
last two to three months3. Your healthcare professional
will perform a blood test to measure your HbA1c and use
this to set a target blood sugar range for you.
If you have type 2 diabetes, every 1% drop in HbA1c
reduces your risk of complications4. The HbA1c
target ranges for people with prediabetes and type 2 diabetes are
shown in this image5.
High and low blood sugar levels
While it is very important to stay within the target HbA1c range
determined by your doctor, it is normal for your blood sugar to
fluctuate throughout the day depending on many factors. However, it
can be dangerous if your blood sugar levels go above or below the
healthy range and are left untreated3.
What is high blood sugar?
High blood sugar, known as hyperglycaemia or 'hypers', damage your
blood vessels. It can reduce the supply of oxygen and nutrient-rich
blood to your body's organs and nerves and, over time, cause serious
health complications6.
Controlling your high blood sugar levels may help you avoid
complications like7:
Heart attack
Stroke
Reduced eyesight or
blindness
Kidney disease
Nerve problems
Blocked circulation in the feet
Gangrene leg
amputations
What is low blood sugar?
Low blood sugar, known as hypoglycaemia or ‘hypos’, occurs when blood
sugar levels fall below 3.9 mmol/L or 70 mg/dL5,8.
Low blood sugar levels can also impact your health8.
What are the signs of low blood sugar?
You may have already experienced low blood sugar without
knowing it. People with diabetes who are on medication need to be
aware of the signs and symptoms of low blood sugar. They may include8:
Shakiness or feeling weak
Sweating, chills and
clamminess
Confusion
Headache
Rapid/fast
heartbeat
Light-headedness or dizziness
Nervousness,
anxiety or irritability
Blurred or impaired vision
Low blood sugar and its symptoms can be dangerous and you need to
know what to do if they happen.
What causes low blood sugar?
You can experience low blood sugar for many reasons, including if you8,9:
do unplanned exercise
have missed or delayed a meal
or snack
take too much insulin or insulin secretagogue
(insulin secretion inducers; sulfonyurea and glinides)
drink alcohol without food
experience stressful
situations
Manage low blood sugar episodes
On average, studies show that people with type 2 diabetes on insulin
treatment experience 23 low blood sugar episodes (mild or moderate)
over a year10.
The effects of low blood sugar can be different for everyone and
hypoglycaemia symptoms can range from mild to
severe8.
Repeated hypoglycaemia can, over time, lead to 'hypo unawareness',
where the warning symptoms of low blood sugar stop being felt, making
it harder to identify and more difficult to manage11.
Download the Hypoglycaemia Profiler to help recognise and track your hypos.
It is important to speak with a doctor or a nurse if you are
experiencing low blood sugar. In some cases, it is a good idea to
drink a fruit juice or eat candies in order to get immediate relief,
or eat sugar tablets if you have them under the recommendation of your
doctor or nurse12. Your doctor can help you find the best
option for you in case of hypoglycemia and may adjust the dose of your
other diabetes medicines to reduce the risk of low blood sugar.
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References
Diabetes UK. Type 2 Diabetes. Available from:
https://www.diabetes.org.uk/diabetes-the-basics/types-of-diabetes/type-2.
Last accessed: July 2024.
Centers for Disease Control and
Prevention. Insulin Resistance and Diabetes. Available from:
https://www.cdc.gov/diabetes/basics/insulin-resistance.html. Last
accessed: July 2024.
Centers for Disease Control and
Prevention. All about your A1C. Available from:
https://www.cdc.gov/diabetes/managing/managing-blood-sugar/a1c. Last
accessed: July 2024.
Lind M, Imberg H, Coleman RL,
Nerman O, Holman RR. Historical HbA1c Values May Explain the Type 2
Diabetes Legacy Effect: UKPDS 88. Diabetes Care. Published online
July 7, 2021.
American Diabetes Association
Professional Practice Committee. 6. Glycemic Goals and Hypoglycemia:
Standards of Care in Diabetes-2024. Diabetes Care. 2024;47(Suppl
1):S111-S125.
Centers for Disease Control and
Prevention. The effects of diabetes on the brain. Available from:
https://www.cdc.gov/diabetes/library/features/diabetes-and-your-brain.html.
Last accessed: July 2024.
Mouri MI, Badireddy M.
Hyperglycemia. [Updated 2023 Apr 24]. In: StatPearls [Internet].
Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available
from: https://www.ncbi.nlm.nih.gov/books/NBK430900/.
Diabetes.co.uk. Hypoglycemia (low blood glucose levels).
Available from:
https://www.diabetes.co.uk/Diabetes-and-Hypoglycaemia.html. Last
accessed: July 2024.
Diabetes.co.uk. Stress and
blood glucose levels. Available from:
https://www.diabetes.co.uk/stress-and-blood-glucose-levels. Last
accessed: July 2024.
Edridge CL, Dunkley AJ, Bodicoat DH,
et al. Prevalence and Incidence of Hypoglycaemia in 532,542 People
with Type 2 Diabetes on Oral Therapies and Insulin: A Systematic
Review and Meta-Analysis of Population Based Studies. PLoS One.
2015;10(6):e0126427. Published 2015 Jun 10.
Diabetes.co.uk.
Hypo Unawareness. Available from:
https://www.diabetes.co.uk/hypo-unawareness.html. Last accessed:
July 2024.
Diabetes.co.uk. How to treat a hypo.
Available from: https://www.diabetes.co.uk/how-to/treat-a-hypo.html.
Last accessed: July 2024.
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