Why Blood Sugar Matters

The rundown on blood sugar

• Blood sugar is the body’s primary fuel and naturally rises and falls in response to eating, movement and daily demands.
• Normal blood sugar levels are described as a range rather than a single number, and can vary depending on whether you’re fasting, eating or active.
• Both low and high blood sugar levels can show up in different ways and are often influenced by meal timing, activity, stress or routine changes.
• Balanced meals, regular eating patterns, hydration, movement and sleep all play a role in supporting healthy blood sugar levels over time.

Blood sugar plays an important role in how the body fuels itself. From the first meal of the day to the last, it shifts in response to eating, movement and daily demands, helping the body meet its energy needs.

Blood sugar, also known as blood glucose, is the main source of energy for cells in the body¹. Inside cells, glucose is broken down to produce energy-rich molecules that power essential cellular processes¹. It helps supply energy to cells, supports brain function and responds to the demands placed on the body throughout the day.

So, what are normal blood sugar levels? And why is it important to balance them? Let’s explore exactly what it is and some practical ways to support healthy blood sugar levels.

What is blood sugar?

When people talk about blood sugar levels or a blood sugar range, they’re generally referring to how much glucose is circulating in the blood at a particular time¹ ².

Glucose is a type of sugar that the body uses as its main source of energy¹. Most of the glucose in the body comes from carbohydrates in food. These carbohydrates are broken down during digestion and released into the bloodstream¹. The glucose is then taken up by cells and used to produce energy that supports everyday processes throughout the body¹. Your body regulates how much glucose remains in the bloodstream and how much is taken up by cells so it can be used efficiently as an energy source². 

Why is blood sugar so important?

Blood sugar levels help support how the body functions day to day. A steady supply of glucose helps support normal physical processes as well as alertness and concentration¹.

The brain also relies on glucose to support thinking processes such as memory, attention and decision-making³. When glucose availability is consistent, it can help the brain carry out these everyday tasks more efficiently³.

Blood sugar balance also plays a role in how energy feels across the day. Large swings in blood sugar levels may leave you feeling drained by the afternoon, while steadier levels tend to support more consistent energy and concentration¹ ².

What is a normal blood sugar level?

Blood sugar levels reflect how the body manages glucose availability for energy, rather than staying fixed at one exact number¹ ². Normal blood sugar levels for adults are usually described as a range, not a single value. This range typically sits between 4.0–7.8 millimoles of glucose per litre of blood (mmol/L), but can vary depending on whether you’re fasting or have recently eaten. Fasting blood sugar (after not eating for at least 8 hours) generally sits at a lower level, while your blood sugar levels will typically rise after eating and then return to fasting levels⁴.

Blood sugar levels can also shift in response to everyday factors such as:

• The type and timing of food eaten
• Physical activity and movement
• Emotional stress or illness

It’s normal for blood sugar levels to move within a range across the day. What matters most is how effectively the body manages these changes to support steady energy, focus and normal body processes⁴.

Symptoms of low blood sugar

Low blood sugar can show up in different ways, and symptoms may vary from person to person. Some common signs that may indicate low blood sugar include:

• Feeling shaky or unsteady
• Light-headedness or dizziness
• Feeling unusually tired or low in energy
• Irritability or mood changes
• Difficulty concentrating or feeling mentally foggy

These signs can appear gradually or come on more suddenly. In many cases, they may be linked to everyday factors such as long gaps between meals, increased physical activity or changes in routine⁵ ⁶. 

If symptoms are frequent, persistent or concerning, it’s important to speak with a healthcare professional for personalised advice and support⁵.

Signs that your blood sugar is too high

Unlike low blood sugar, which can sometimes be felt quickly, high blood sugar levels often develop more gradually. The signs aren’t always obvious at first and may build over time as the body works to manage excess glucose.

Common high blood sugar symptoms may include:

• Feeling more tired or lethargic than usual
• Increased thirst
• Needing to urinate more frequently
• Difficulty concentrating or feeling mentally foggy
• Feeling generally unwell or low in energy

These signs are often linked to how the body regulates fluids and energy when glucose levels remain elevated. Factors such as food choices, reduced activity, stress or illness can all influence how blood sugar is managed from day to day⁵ ⁷.

If symptoms are ongoing, worsening or feel out of the ordinary, it’s important to speak with a healthcare professional for personalised advice⁵.

How to control blood sugar levels

Small, consistent habits can make a meaningful difference to your body’s sugar balance, supporting how steadily energy is released and how the body responds to food across the day. Here are some ways to help support your blood sugar levels: 

• Eating a balanced meal: Balancing carbohydrates with protein and healthy fats can help slow digestion and support a more gradual release of glucose into the bloodstream^{8 9}. Including fibre-rich foods, such as whole grains, vegetables, legumes and foods containing fibres, can also support this process⁹.
• Eating at regular times: Spacing meals consistently through the day, rather than skipping meals or eating very late at night, can help support steadier blood sugar responses¹⁰. This rhythm can help the body anticipate energy needs and respond more smoothly to food intake.
• Hydration:  A simple but often overlooked habit, drinking enough water helps the body function efficiently throughout the day⁸.
• Regular movement: Gentle, consistent physical activity like walking or stretching has been shown to influence how the body manages glucose after meals^{8 10 11}. 

Why everyday habits matter for normal sugar levels

Your blood sugar levels aren’t shaped by one meal or one day. Instead, everyday habits around eating, movement and sleep work together to support how the body manages glucose as part of normal daily functioning¹¹.

Nutrition plays a role, but it doesn’t act alone. Regular movement helps the body use glucose more efficiently after meals, while consistent sleep patterns support how the body responds to food across the day^{10 11}. When these habits are out of sync, blood sugar responses can feel less steady.

Stress and lifestyle patterns also matter. Busy schedules, disrupted routines or eating late at night can influence how the body processes glucose¹⁰.

Looking for more guidance on wellness? Explore the Swisse Wellness Hub for articles including how to restore your electrolyte balance and how to make time for mindfulness.  

References:

1. Lema-Pérez, L. (2021). Main Organs Involved in Glucose Metabolism. In Sugar Intake - Risks and Benefits and the Global Diabetes Epidemic. IntechOpen. https://www.intechopen.com/chapters/74163
2. Gupta, S. R. N. (2025). Quantitative measurement of concentration of glucose in whole blood of teaching staff, non-teaching staff and postgraduate students and their data analysis category wise and classification wise. International Journal of Science and Research Archive, 15(2), 1718–1741. https://doi.org/10.30574/ijsra.2025.15.2.1342
3. Arshad, M. T., Maqsood, S., Altalhi, R., Shamlan, G., Mohamed Ahmed, I. A., Ikram, A., & Abdullahi, M. A. (2025). Role of dietary carbohydrates in cognitive function: A review. Food Science & Nutrition, 13(7), e70516. https://doi.org/10.1002/fsn3.70516
4. Diabetes Australia. (2025). Blood glucose level range. Diabetes Australia. https://www.diabetesaustralia.com.au/managing-diabetes/blood-glucose-range/
5. Healthdirect Australia. (2024). Hypoglycaemia (low blood sugar). Australian Government. https://www.healthdirect.gov.au/hypoglycaemia-low-blood-sugar
6. Loumpardia, P., & Huda, M. S. B. (2019). Symptoms of hypoglycaemia. In Blood Glucose Levels. IntechOpen. https://www.intechopen.com/chapters/69558
7. Mouri, M., & Badireddy, M. (2023). Hyperglycemia. In StatPearls. National Library of Medicine. https://www.ncbi.nlm.nih.gov/books/NBK430900/
8. Zhang, X., Imperatore, G., Thomas, W., et al. (2017). Effect of lifestyle interventions on glucose regulation among adults without impaired glucose tolerance or diabetes: A systematic review and meta-analysis. Diabetes Research and Clinical Practice, 123, 149–164. https://doi.org/10.1016/j.diabres.2016.11.020
9. Pasmans, K., Meex, R. C. R., van Loon, L. J. C., & Blaak, E. E. (2022). Nutritional strategies to attenuate postprandial glycaemic response. Obesity Reviews, 23(9), e13486. https://doi.org/10.1111/obr.13486
10. Papakonstantinou, E., Oikonomou, C., Nychas, G., & Dimitriadis, G. D. (2022). Effects of diet, lifestyle, chrononutrition and alternative dietary interventions on postprandial glycaemia and insulin resistance. Nutrients, 14(4), 823. https://doi.org/10.3390/nu14040823
11. Yao, J., Brugger, V. K., Edney, S. M., et al. (2024). Diet, physical activity, and sleep in relation to postprandial glucose responses under free-living conditions. International Journal of Behavioral Nutrition and Physical Activity, 21(1), 142. https://doi.org/10.1186/s12966-024-01693-5