Normal blood sugar levels

While almost everyone’s heard of blood sugar, not everyone understands its effect on overall health. A major factor in determining your wellbeing, it’s essential to understand the fundamentals of blood glucose levels and how they can affect your body.
Rin Mosher
min read
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Quick summary

  • Blood sugar is a major factor in overall health
  • Blood sugar and type 2 diabetes are interrelated
  • Managing blood sugar is key to bolstering overall health and living with type 2 diabetes
  • There are plenty of measures that can be taken to improve and manage blood sugar

Thanks to the modern lifestyle, blood sugar is a prevalent issue in today’s society for millions of us around the world and when out of control, can have a serious impact on overall health and wellbeing. Type 2 diabetes, a condition identified by excessively high blood sugar levels, affects 90% of the 4.9 million people in the UK living with diabetes.[1] Despite this, many of us don’t even think about blood sugar levels… until there’s a problem. Blood glucose levels can impact everything from hunger pangs and cravings, to circulation and mental health—they’re a powerful driver of health, so let’s get started on the basics of blood sugar.

What is blood sugar?

Blood sugar is generated from the food you eat and is used by your body for energy. Your body produces blood sugar by digesting the food you eat into a type of sugar that then circulates in your bloodstream.

Blood sugar levels, also called blood glucose levels, are a measurement of how much sugar (glucose) is in your bloodstream. Glucose is a type of sugar that we get through our food and drink. After we eat, the food is broken down during digestion and the amount of glucose in our bloodstream increases. Our bodies need glucose for energy, so different parts of it (such as the muscles) take glucose from the bloodstream to fuel their work. They do this with the help of a hormone called insulin, which helps the glucose move out of your bloodstream into different parts of the body, where it’s either used immediately or stored for future use. 

Blood sugar levels fluctuate throughout the day in absolutely everyone, regardless of whether you have type 2 diabetes or not, and they’re affected by many things including what we eat, how much we drink, and our levels of movement. People with type 2 diabetes struggle to produce insulin at high enough levels or are unable to use it properly. When this happens, the amount of glucose in the blood continues to rise because it can’t be taken out of the bloodstream and used. If blood sugar levels continue to rise and remain high for too long, they can cause serious complications around the body. Type 2 diabetes is a condition characterised by high blood sugar levels and if left unnoticed, can go on to cause problems in the kidneys, eyes, heart, nerves, and blood vessels.   

Why are high blood sugar levels bad?

High blood sugar levels (called hyperglycaemia) can be damaging to your body in a number of ways. In the short term, this elevated blood sugar commonly results in dehydration or abnormally high thirst and urination. Consistently high levels of blood sugar over an extended period of time can lead to several different health problems, including:[2]

  • Heart disease and stroke: high blood sugar is one of the main risk factors for heart disease.
  • Nerve damage: high blood sugar damages nerves throughout your body, which can cause pain or loss of sensation.
  • Kidney disease: the kidneys clean waste from the blood and high blood sugar can damage them internally, leading to a build-up of harmful waste products in the blood and kidney failure.
  • Eye problems: high blood sugar can damage tiny blood vessels in your eyes, which may cause blurred vision, halos around lights, and increases the risk of eye infections.
  • Skin problems: high blood sugar can damage the small blood vessels in your skin, which may cause it to be more fragile and slow healing after an injury. It can also lead to scaling, itching, and rashes such as fungal infections.

With the right support and management, up to 50% of cases of type 2 diabetes can be prevented or delayed

Diabetes UK

The complications of high blood sugar levels are wide-reaching, which is why it’s important to understand blood sugar and take steps to manage it, especially if you have been diagnosed with type 2 diabetes. The main thing to remember here is that the risk of these problems occurring can be minimised with good blood sugar level control and small changes can make a huge difference.

What are normal blood sugar levels?

As we’ve already mentioned, it’s completely normal for blood sugar levels to fluctuate throughout the day. Factors affecting blood sugar include age, activity level, the time of day, the food you’ve eaten, hormones, and even sleep. While it’s not always possible to reduce a spike in blood glucose, it’s important to try and keep levels as steady as possible throughout the day—they’ll rise and fall but it’s more about keeping these peaks and troughs to a minimum. 

For people without diabetes, ‘normal’ blood sugar levels are 4-5.4mmol/l before eating and less than 7.8mmol/l 2 hours after eating. If you have type 2 diabetes, you’ll be advised to keep your blood sugar levels within a certain range—everyone is different and so is your ‘target range’, but as a guideline, they should be 4-7mmol/l before eating and less than 8.5mmol/l 2 hours after meals.[3]

If your blood sugar levels are higher than normal but not quite as high as the levels that indicate type 2 diabetes, you may have pre-diabetes. Pre-diabetes is an indicator that you’re at high risk of developing type 2 diabetes—you are unlikely to be experiencing any of the symptoms associated with type 2 diabetes. With the right support and management, up to 50% of cases of type 2 diabetes can be prevented or delayed.[4]

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How do you know if you have type 2 diabetes?

Type 2 diabetes is characterised by continuously high blood sugar levels but many people develop the condition without realising it. This is partly because the symptoms of type 2 diabetes may not make you feel unwell but if you notice any of the following, it’s important to speak to your doctor:[5]

  • Weight changes: losing or gaining weight unintentionally can be a sign of problematic blood sugar levels.
  • Frequent urination: needing to urinate more than normal, especially at night, might indicate that your kidneys are having trouble keeping up with removing glucose from the body, leading to high blood sugar levels.
  • Unusual thirst: if you feel thirsty all the time even though you are drinking plenty of water, your kidneys might be struggling to filter sugar from the blood.
  • Fatigue: if you are feeling persistently very tired it could be a sign your insulin levels are too high for you to process the glucose in the body.
  • Blurred vision: glucose builds up in the blood and tears when it should be being processed by insulin, which can cause blurry vision.
  • Tingling in hands or feet: if your hands or feet are tingling, it could be a sign that you need to check blood sugar levels.
  • Cuts or wounds that take longer to heal: high blood sugar levels can slow down your circulation, making it more difficult for the body to deliver the necessary nutrients to promote healing.

How to manage blood sugar levels

There are a number of things you can do to help keep your blood sugar levels stable and under control. 

👀 Monitor blood sugar levels

If you have type 2 diabetes, you’ll have a regular HbA1c test, which is likely how you will have been diagnosed. This is a blood test that measures your average blood sugar level over the previous 3 months. 

People with type 1 diabetes have to self-monitor their blood sugar levels because their main treatment option is insulin injections. While not strictly necessary to self-monitor your levels if you have type 2 diabetes, it can be a helpful and insightful way to effectively manage your blood sugar. By keeping an eye on your levels, you can determine whether any blood sugar medications you’ve been prescribed are working, monitor the impact of diet and exercise on your levels, and see whether other factors such as stress or illness affect you. This is all useful information to have to help you build a thorough and personalised diabetes management plan with your doctor. Some people will be able to get a blood sugar monitor via prescription, while others may have to purchase them. Speak to your doctor to find out more about self-monitoring blood sugar and whether it's the right thing for you to do.

🥕 Eat a balanced diet

A healthy balanced diet is one of the most important things you can do to keep your blood sugar levels stable. Here are three practical things you can start doing straightaway—remember, small changes can have a big impact!

  • Moderate your carbohydrate intake: carbohydrates are easily broken down into glucose, meaning they have a bigger impact on blood sugar levels than fats or proteins. Be mindful of the amount of carbs you eat and where possible opt for whole-grain complex carbohydrates, such as brown rice, brown bread, and brown pasta. These take longer to break down, meaning that rather than causing a glucose spike, there’s a longer, more controlled response.
  • Eat at regular intervals: skipping meals can cause blood sugar to peak and trough. This yo-yo effect can severely impact your hunger pangs and cravings, causing you to reach for more snacks. Eating balanced meals at regular intervals will help keep your blood sugar levels stable.
  • Watch your portion sizes: particularly relevant when it comes to carbohydrates, it’s helpful to be aware of your portion sizes. Official guidance is for carbohydrates to take up just over a third of the food you eat but remember, this is only a guideline.[6] More than anything it's about balance—if you have pasta for dinner, try and have a meal that’s lower in carbs for lunch. Food combining is also another interesting approach, in which eating foods in certain combinations have been shown to aid nutrient absorption and keep blood sugar levels under control.

💧 Drink plenty of water

Type 2 diabetes leaves you susceptible to dehydration and spikes in blood sugar have the same effect. Try to take a few sips of water every hour rather than waiting until you feel thirsty (by this point, you’re already dehydrated!). There are plenty of ways to make plain water more interesting but do try to steer clear of sugary drinks and fruit juice as these contain a high amount of sugar, causing rapid spikes in blood sugar.

🏃 Exercise regularly

There are countless reasons why exercise is good for you but in this context, it’s great at helping your body use glucose efficiently. Rather than embark on a massive exercise plan, think about small changes you can make to add more movement into your day—walk for 15 minutes after breakfast, get off the bus a stop earlier, stretch while the kettle boils, march on the spot during TV adverts. Even just 10 minutes up to 90 minutes after a meal can help curb a dramatic increase in blood sugar levels as muscles take glucose from the blood for fuel.[7]

💊 Take your prescribed medications

If you’ve been diagnosed with type 2 diabetes, you may have been prescribed medication designed to help control blood sugar levels. Over time, the amount of medications and their dosage may increase, and it's important to note that while they are safe, they do not treat the underlying cause of type 2 diabetes. Combining lifestyle changes, such as to your diet and exercise routine, with medication can help lower blood sugar levels enough that you may be able to reduce or stop your medication entirely! Before making changes to your diet or exercise routine, speak to your doctor—it’s important they know what you’re planning to do 

Making changes to maintain stable blood sugar levels is worth doing whether you have type 2 diabetes or not—as we’ve seen, blood sugar has a wide-ranging effect on the body. It’s normal to feel uncertain about changing your normal routine but with the right approach, working to minimise blood sugar level fluctuations can have a hugely positive impact on how you build a healthier lifestyle in the years to come.


[1] Diabetes diagnosis doubles in the last 15 years. Diabetes UK. Retrieved 2 February 2022. Accessible here

[2] Health problems—Type 2 diabetes. NHS. Retrieved 2 February 2022. Accessible here.

[3] Checking your blood sugar levels. Diabetes UK. Retrieved 2 February 2022. Accessible here.

[4] Prediabetes. Diabetes UK. Retrieved 2 February 2022. Accessible here.

[5] Symptoms—Type 2 diabetes. NHS. Retrieved 2 February 2022. Accessible here.

[6] Starchy foods and carbohydrates—Eat well. NHS. Retrieved 2 February 2022. Accessible here.

[7] Borror, A., Zieff, G., Battaglini, C., Stoner, L. (2018). The Effects of Postprandial Exercise on Glucose Control in Individuals with Type 2 Diabetes: A Systematic Review. Sports Med 48:1497-1491. Accessible here.

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