Metabolic Health 19 MIN READ

The Ultimate Guide To Glucose Monitoring And Optimising

Have you been curious about blood glucose but unsure about how to navigate through the glucose maze? We’ve got you covered!

Written by Team Ultrahuman

Nov 02, 2021

Have you been curious about blood glucose but unsure about how to navigate through the glucose maze? Our body depends on glucose to keep its mechanisms functioning efficiently, giving us the energy to go about our day-to-day activities. Our glucose levels often go unnoticed when they are at their ideal levels. However, when they stray from recommended boundaries, our normal functioning is affected.

Good sources glucose


  • Our body depends on glucose to keep its mechanisms functioning efficiently, giving us the energy to go about our day-to-day activities,
  • Insulin is a hormone created by the pancreas that controls the amount of glucose in a person’s bloodstream at any given moment,
  • Glucose metabolism⁠ is a fundamental part of life, and why hyperglycemia, hypoglycemia, metabolic syndrome, and diabetes can be life-threatening conditions.

What is Glucose?

Glucose is a simple sugar, making it a monosaccharide, a subcategory of carbohydrates. In addition to fat, glucose is the preferred source of fuel for the body, in the form of carbohydrates. Bread, fruits, vegetables, and milk are good sources of glucose. There is a complex system in place for keeping glucose within a healthy range, metabolising it into fuel or storing it for later use. Insulin plays a crucial role in this process.

What is Insulin?

Insulin is a hormone created by the pancreas that controls the amount of glucose in a person’s bloodstream at any given moment. It helps store glucose in the liver, fat, and muscles, and regulates the body’s metabolism of carbohydrates, fats, and proteins. Our bodies need insulin to convert food into energy. As we eat, two things take place in the body: First, the small intestine breaks down the carbohydrates in the food and turns them into glucose, which is then absorbed into the bloodstream. Second, the pancreas produces and releases insulin to keep blood sugar levels in check.

What is Insulin Resistance?

Insulin resistance occurs when the body is not able to use insulin effectively. The cells of the body do not react to insulin in the way they are meant to, which in turn increases the level of blood sugars in the body. If insulin resistance is left unchecked, it could become a reason for health conditions that require long-term monitoring and treatment.

What is Insulin Sensitivity?

The cells of the body require glucose to function and insulin helps move the glucose into the cell. This is a key step in making sure that the blood sugar is at healthy levels at all times. Insulin sensitivity, as the name suggests, is an indicator of how sensitive the cells are to insulin. High insulin sensitivity indicates that the blood glucose is being efficiently used by the body, and vice versa. Some lifestyle changes can help improve insulin sensitivity.

What is Glucose Metabolism?

When we eat, our body immediately begins to process glucose with the help of the pancreas, its enzymes beginning the breakdown process. Glucose metabolism can be described as the process by which our cells receive nourishment. Consequently, without food, our cells would starve. This is why glucose metabolism⁠ is a fundamental part of life, and why hyperglycemia, hypoglycemia, metabolic syndrome, and diabetes can be life-threatening conditions.

Ingestion and digestion of carbohydrates initiate glucose metabolism. As soon as the carbohydrates are broken down completely, the simple sugars⁠ fructose, glucose, and galactose⁠ are left behind. Fruits and vegetables are the sources of fructose, while dairy products are the sources of galactose. Sugar comes from grain. Fructose and galactose combine to form glucose.

body processes glucose

How does the body process Glucose?

The glucose moves through the body in the following sequence:

  1. When you start eating, receptors on your tongue, gut, and pancreas sense carbohydrates. This sets off a chain of events telling the body to process and use this fuel.
  2. A complex set of signalling instructions is triggered as soon as the body detects glucose. The glucagon-like peptide-1 (GLP-1). For example, stimulates the pancreas’ beta cells to produce and release an increased amount of insulin, which helps deliver glucose to the cells and helps the cells take it in. 
  3. Polysaccharides are broken down into glucose by enzymes in your saliva, pancreas, and small intestines. Which enzyme does the job depend on the form of the carbohydrate: amylase can be found in starches, lactase in lactose, sucrase in sucrose, and so on.
  4. As glucose enters the bloodstream, it is transported by several different transporter molecules, including the glucose transporters SGLT and GLUT. After it passes through the epithelial cells lining the small intestine, it moves into the blood vessels. As soon as glucose enters the bloodstream, it passes through the liver, where it either turns into glycogen and is stored for later use, or continues to circulate.
  5. Insulin (and other hormones) help cells absorb glucose once it has reached the cells. In muscle and fat cells, insulin binds to receptors on the cell surface and causes GLUT4 channels to form at the cell membrane, allowing glucose molecules to enter. Other cells have different glucose transporters.
  6. Glucose is not all used immediately; some is stored (a process that is also controlled by insulin). Glucose can be converted into glycogen and stored in the liver or muscles, or into triglycerides and stored in fat tissue. The main source of fuel for our cells is glucose. Glucose that is stored in the liver and muscles is made up of many connected glucose molecules and is called glycogen.
  7. When the body needs a quick boost of energy or when the body isn’t getting glucose from food, glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells. The process of converting glycogen into glucose is referred to as glycogenolysis. Glucagon controls the release of glucose, while insulin allows glucose to be stored.
  8. A body can produce glucose if it needs more than it consumes. Glucose is primarily produced in the liver. A process called gluconeogenesis is roughly the opposite of glycolysis, where glucose is broken down. During a fast or when you have eaten a few carbs, your body will resort to gluconeogenesis to fuel certain organs, such as the brain (which consumes 60% of your blood glucose while fasted or sedentary, and stores minimal glycogen).

What is Gluconeogenesis?

Gluconeogenesis, also called glucogenesis, is the formation of glucose from other compounds within living cells. Some of these compounds include lactate and pyruvate, tricarboxylic acid cycle compounds, and a number of amino acids. The liver and kidneys produce glucose primarily; for example, the liver synthesises glucose from lactate during recovery from strenuous exercise.

Several reactions in the gluconeogenetic pathway are catalysed by the same enzymes that catalyse glycolysis in the reverse sequence, but two crucial steps are influenced by other enzymes. The process is influenced, among other things, by the balance of various hormones, particularly cortisol from the cortex of the adrenal glands and insulin from the pancreas.

What is Glycogenesis? How does the liver process Glucose?

Glycogenesis is a process in which glucose is converted into glycogen, the main carbohydrate stored in liver and muscle cells. When blood glucose levels are sufficiently high, excess glucose is stored in the liver and muscle cells. Insulin promotes glycogenesis. It facilitates glucose uptake into muscle cells but is not required for glucose transport into liver cells. The insulin hormone, however, has profound effects on glucose metabolism in liver cells, stimulating glycogenesis and inhibiting glycogenolysis, the breakdown of glycogen into glucose.

What is Glycemic Variability?

Our glucose levels give us an insight into our bodies when they vary over time. A metric known as glycemic variability (glucose variability) can be used to identify these internal oscillations in blood glucose levels, measured by how they vary over time. The SD (Standard Deviation) is the most widely used method to calculate variability. It represents the spread in glucose readings around the average.

As an example, if someone has been alternating between many highs and/or lows on a given day, their SD will be larger. In contrast, if someone has a relatively stable day, their SD will be lower. A glucose excursion can be either hyperglycemic (high blood glucose) or hypoglycemic (low blood glucose).

We can determine how frequently an individual’s blood sugar levels are significantly above or below the target/ideal range by determining the variability of blood sugar levels. Variability in glucose represents the quality of fuel and the amount of oxidative stress on your body. A blood glucose variability under 12% is considered ideal.

Hypoglycemia and Hyperglycemia

What is Hypoglycemia? 

Hypoglycemia, or low blood sugar, occurs when your blood glucose level drops below what is healthy for you. This means a blood glucose level below 70 milligrams per deciliter (mg/dL) for most people with diabetes. People who don’t have diabetes can also get low blood glucose levels. Non-diabetic hypoglycemia can take two forms:

Reactive Hypoglycemia, occurs shortly after a meal.

Hyperinsulinemia, or reactive hypoglycemia, occurs when your blood contains too much insulin. It usually occurs after eating. It can also be caused by:

  1. Prediabetes or an increased risk of diabetes
  2. Post-surgical complications
  3. Rare enzyme deficiencies

Fasting Hypoglycemia, is caused by medicine or disease.

There are several causes of fasting hypoglycemia:

  1. Medications, such as aspirin and sulfa drugs
  2. Excessive alcohol consumption
  3. Disorders of the liver, kidney, heart, and pancreas
  4. Low levels of hormones
  5. Some tumours

What is Hyperglycemia?

High blood sugar, or hyperglycemia, occurs when there is too much sugar in the blood, and when your body doesn’t have enough insulin (the hormone that transports glucose into the bloodstream) or can’t effectively use insulin. It is usually associated with diabetes. If your blood glucose level is greater than 125 mg/dL (milligrams per deciliter) while fasting, you have hyperglycemia.

  • Fasting Hyperglycemia

A person with impaired glucose tolerance has a fasting blood glucose of 100 mg/dL to 125 mg/dL, or pre-diabetes.

  • Postprandial or After-Meal Hyperglycemia:

One to two hours after eating, a person has hyperglycemia if their blood glucose is over 180 mg/dL. Leaving hyperglycemia untreated for long periods can cause damage to your nerves, blood vessels, tissues, and organs. Blood vessel damage can increase your risk of heart attack and stroke, and nerve damage may cause eye damage, kidney damage, and non-healing wounds.

Glucose Variability and Oxidative Stress

Glucose levels at various points in time provide insight into the body’s functioning. They make for a metric that can be used to identify internal oscillations in blood glucose levels known as glucose variability. Extreme fluctuations in blood glucose levels can lead to oxidative stress in the body. Variability in blood sugar can be caused by a variety of factors, such as a poor diet, infections, tumours, or other diseases like diabetes. Long-term oxidative stress can cause neurodegenerative diseases, cancer and hypertension among other ailments. Monitoring glucose swings may provide actionable insight into preventing oxidative stress since the two can increase together. 

How to measure Blood Glucose levels

1. A1C test: A1C measures your average blood sugar levels over the past two or three months. A normal A1C level is below 5.7%, a level of 5.7% to 6.4% indicates prediabetes, and a level of 6.5% or more indicates diabetes.

2. Fasting blood sugar test: After an overnight fast (without eating), your blood sugar is measured. Having a fasting blood sugar level of 99 mg/dL or less is considered normal, 100 to 125 mg/dL indicates prediabetes, and 126 mg/dL or higher indicates diabetes.

3. Glucose tolerance test: A glucose-containing liquid is consumed before and after this device measures your blood sugar. Before the test, you will fast overnight and have your blood drawn to determine your fasting blood sugar level. After drinking the liquid, your blood sugar level will be checked for one hour, two hours, and possibly three hours later. After two hours, a blood sugar level of 140 mg/dL or lower is considered normal, 140 to 199 mg/dL indicates prediabetes, and 200 mg/dL or higher indicates diabetes.

4. Random blood sugar test: The blood sugar level is measured at the moment you are tested. It is possible to take this test at any time. You do not need to fast before taking it. Diabetes is diagnosed when your blood sugar level exceeds 200 mg/dL.

5. Post-meal glucose: Blood sugar levels are determined not only by fasting glucose but by how your body reacts to food and its ability to return to that set-point quickly. We expect glucose to rise after a meal (though if we eat carefully, it won’t rise much). If your body is not able to return to that baseline quickly, you may have insulin resistance, which prevents insulin from functioning well. We can gain some insight into that function by measuring post-meal glucose levels.

6. Continuous Glucose Monitoring: We become more aware of the limitations of single-point measurements when we are aware of the damage caused by high and low blood sugar levels. The A1C or FPG of a person whose glucose levels spike and crash regularly could still be “normal.” The sensor can be inserted under the skin of your belly in a quick and painless manner, or it can be applied to the back of your arm. A transmitter on the sensor then sends information to a wireless belt-clip monitor that looks like a pager. Your sugar level is displayed every 1, 5, 10, or 15 minutes.

Your monitor will sound an alarm if your sugar drops to a dangerously low level or a high preset level. This information can be used together with your doctor to create a personalised plan to manage your diabetes, including how much insulin to take, how many meals and snacks you should eat each day, and what medications you should take. A research paper recently concluded that “Continuous glucose monitoring is more sensitive than HbA1c and fasting glucose in detecting dysglycemia (an abnormality in blood sugar stability including both hypoglycemia or hyperglycemia) in a Spanish population without diabetes.”

Glycemic variability
It refers to the ups and downs of blood glucose levels during the day. You can only measure this with a continuous glucose monitor, which measures the interstitial fluid under your skin throughout the day.

Importance glucose monitoring

Importance of Monitoring Glucose

It is important to monitor your blood sugar levels to determine if you are meeting your glucose targets, and reducing the symptoms of high and low blood sugar, by tracking your numbers, you can determine what makes them fluctuate, such as eating different foods or being physically active. You should remember that numbers neither mean good nor bad things, but translate into insights to help you learn what is working well and identify areas for improvement for optimal metabolic health.

Consequences of Glucose levels going unregulated

Metabolic health is described as having ideal levels of blood sugar, triglycerides, high-density lipoprotein (HDL) cholesterol, blood pressure, and waist circumference, without using medications.

Metabolic syndrome refers to a group of conditions that simultaneously occur, elevating your risk of heart disease, stroke and type 2 diabetes. These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels. Blood sugar levels before and after eating are among the most important markers. Your pre- and post-eating blood sugar levels might be harder to test in a regular medical setting, but the comprehensive metabolic panel (CMP) covers your fasting blood glucose. Fasting blood glucose less than 99 mg/dL is considered ‘normal,’ but doctors recommend a number around 70 or 80 mg/dL.

Please refer to the table below for,

Ideal range of Blood Glucose Levels Acc. Center for Disease Control and Prevention

blood Glucose Levels

Essentially, insulin is a hormone released by your pancreas when you eat or drink something. When food is digested, it is converted into sugar (or glucose) that enters your bloodstream. By releasing glucose into your blood, your pancreas secretes insulin, the key that “unlocks” your cells, allowing them to pull sugar from your blood and convert it to energy. The pancreas overproduces insulin when sugar is constantly pumped into the bloodstream, and your cells stop responding to it as a result. This is known as insulin resistance.

Even though your pancreas tries harder to force the cells to respond, it cannot sustain the effort forever. Sugar in your blood cannot reach your cells, so your blood sugar levels stay high for a long time. It puts you at a heightened risk of diabetes, which increases your risk of heart disease and developing metabolic syndrome. Regularly monitoring blood glucose levels can avert the risk of developing chronic health conditions and metabolic syndrome.

What do Blood Glucose spikes at night mean?

The Somogyi effect

High blood sugar levels in the morning are generally caused by ill-timed insulin, which depletes blood sugar so much at night that hormone secretion causes a rebound. A sharp spike in glucose levels occurs after a fast or a missed meal. Night sweats are often associated with the condition.

The Dawn effect 

As the name suggests, it occurs at dawn when there is an abnormal increase in blood sugar levels from being asleep. In this scenario, hyperglycemia occurs as the body prepares to rise and get ready for the day. Hypoglycemia or low blood sugar levels leading up to bedtime are significant causes of the spike in blood glucose at night. Glucagon and epinephrine are released by the body when glucose levels drop dramatically. These hormones cause the liver to convert glycogen into glucose.

Glucose levels and Athletic Performance

When it comes to athletic performance and exercise, your glucose level plays a critical role. Those who perform intense exercises or are running marathons should maintain a healthy glucose level. If that number drops below what is considered normal, they should replenish their body with glucose before doing any more strenuous activity. 

Athletes need proper nutrition to maximise their performance for training and competition. The macronutrient targets an athlete should have will depend on the sport, the time of exercise, and the season. They should set both daily and activity-specific goals for obtaining the fuel needed for successful training. Athletes have many strategies they can use when fuelling for performance. Diet plays an important role in optimising training sessions, as well as in recovery and metabolic adaptation.

Your body’s energy is measured in calories. Dietary macronutrients include carbohydrates, proteins, and fats. Different macronutrients contain different amounts of energy. Unlike fat, which contains 9 calories per gram, protein and carbohydrates contain 4 calories each. Since fat represents the most energy per gram, you may assume that fats are the best choice for athletic performance. But this is not as simple as it seems.

Carbohydrates provide less energy and are more easily digestible. Even though fat molecules offer more energy, they take longer to disband and become fuel. When used skillfully for energy, fats and carbohydrates can both enhance performance.

Optimising glucose diet

How to optimise Blood Glucose levels

1. Sleep: Sleep and glucose metabolism go hand in hand. A lack of sleep can affect glucose regulation by increasing circulating cortisol (a stress hormone), leading to gluconeogenesis (the production of glucose from non-carbohydrate sources). In a study, it was discovered that 6 days of sleep restriction was associated with an increase in evening cortisol levels and nighttime growth hormone concentrations, resulting in a rapid drop in muscle glucose uptake.

2. Stress: The sympathetic nervous system controls the body’s response to danger. Stress stimulates the sympathetic nervous system, which releases cortisol. Besides regulating blood pressure and blood sugar levels, cortisol is the body’s natural alarm system. As a result of increased glucose levels as an immediate energy source, cortisol inhibits insulin sensitivity in stressful situations. Chronic stress and chronically elevated glucose levels cause the pancreas (which produces insulin to lower glucose levels in the blood) to become less effective at responding to a high glucose stimulus, causing a drop in insulin activity.

3. Exercise: Exercises like HIIT, resistance training, aerobics, and low-impact cardio are often recommended. Exercise can be segmented into vigorous/intense workouts and low/moderate intensity exercises. In anaerobic activity, glucose is broken down without oxygen being used for energy. By using an incessant supply of oxygen, aerobic activity produces energy without any additional energy source. HIIT uses fast-twitch muscle fibres, while aerobic exercise uses slow-twitch muscle fibres. While HIIT enhances cardio-metabolic metrics and bone formation, aerobic exercise is associated with fat metabolism. Exercise is proven to not only improve insulin sensitivity but also improve metabolic health.

4. Diet: Glycemic Index refers to a relative measure of the incremental glucose response per gram of carbohydrate. This has proven to be a more reliable parameter for defining carbohydrates than complex and simple carbs, with important implications for the food industry. Low GI foods are associated with smaller fluctuations in blood glucose levels in comparison with foods with high GI. However, the GI tells only part of the story about the carbohydrate content of food. Some criticize its ranking system for not reflecting a food’s overall healthfulness. In this discussion, both glycemic load and glycemic variability are relevant. Considering a food’s nutritional value as a whole is recommended.

Advertisements, the news, and popular fitness pages portray many foods as good for your blood sugar. However, many of these foods can actually be harmful. It is even possible for wholesome foods to cause blood sugar spikes. We need to carefully monitor foods like oatmeal, brown rice, fresh fruit juice, sweet potatoes, etc. Low glycemic index foods are known to lower blood sugar levels.

In 1995, 2002, and 2008, international tables of GI values were published. According to some, the GI values of the same foods vary over such a wide range that their GI cannot be predicted. There may be differences in food GI values because of differences in variety, processing, growing conditions, and so forth. Not all carbohydrates are created equal. The glycemic index (GI) ranks carbohydrates in food on a scale from 0 to 100, according to their blood sugar-raising potential.

Although Glycemic Index (GI) isn’t an exact measurement, it does indicate how the body digests or absorbs food (especially carbohydrates), influencing blood glucose levels. According to sources, foods with a low GI (up to 55) to moderate GI (56-69) include legumes, barley, yoghurt, oats, and beans. According to a study, a low-carbohydrate diet, high in saturated fat, improved insulin-resistant dyslipoproteinemia and lipoprotein(a) without adverse effects on LDL cholesterol.

It is also important to avoid high levels of sugary foods and drinks, trans fats, and simple carbohydrates or foods with a high glycemic index and glycemic load. The Mediterranean diet may also reduce insulin resistance. In this diet, the main focus is on eating seasonal foods and using plant-based fats, such as olive oil for cooking and certain fruits for desserts. The main sources of protein in this diet are fish, poultry, legumes, and nuts.


A major source of energy for your cells, glucose is one of the most crucial molecules in your body. Disruptions in glucose levels can affect every cell in our bodies, from the skin to the brain to our organs to our nervous system, because glucose affects every cell. It can also disrupt hormones, such as insulin, causing more health problems. Fortunately, we can control our glucose levels. With the right combination of aerobic (uses oxygen to break down glucose) and anaerobic exercises (glucose is broken down without oxygen), one can not only improve insulin sensitivity but also improve metabolic health.

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.


  1. Digestive System Processes
  2. Glycemic Variability: Should we and can we prevent it?
  3. An overview of insulin
  4. Hypoglycemia
  5. High Blood Sugar and Diabetes

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