If you have clients struggling with fatigue – do they know what their blood sugar levels are? Blood sugar levels can either be checked by requesting the HbA1c blood test (3 month average of blood sugars) from the GP and/or by using a blood sugar monitor at home. The healthy blood sugar range is between 4 – 7 mol/L (or an HbA1c under 42 mmol/mol).

High blood sugar levels can cause fatigue…1

After a catastrophic injury, weight gain is common (2, 3) and this can lead to pre-diabetes or Type 2 diabetes, both of which cause high blood sugar levels.  

Foods which increase blood sugar levels include any food with carbohydrate (eg. Starchy foods, fruit, milk and food with added sugar).  After you eat a carbohydrate-rich food or meal, the body will try to produce sufficient amounts of insulin to stop blood sugar levels from rising too high.  Insulin’s job is to move the sugar (glucose) from the bloodstream into the body’s cells for energy.  In people with pre-diabetes and diabetes, this system isn’t working correctly and their body either doesn’t produce enough insulin or the insulin they are producing isn’t working properly.  In both cases, blood sugar levels end up too high which can cause a variety of health problems ranging from fatigue and oral/vaginal thrush to cardiovascular disease and kidney damage.1,4

…low blood sugar levels can cause fatigue as well.5

Most people know that clients on insulin have to be careful about their blood sugar levels going too low.  However, even in clients without diabetes, I have come across a few cases where fatigue levels were directly linked to blood sugar levels spiking quickly and then dropping just as fast (also called rebound hypoglycaemia).6  This can be a consequence of eating foods very high in refined carbohydrate (eg. white bread/rice/crackers/biscuits/cold cereals), particularly if there is very little fat or protein at that meal.  Symptoms tend to occur 2-4 hours after eating.  I’ve also had clients where low blood sugar levels were caused by skipping meals and erratic eating habits.  The only way to know if the fatigue is due to low blood sugar levels, is to test with a monitor at home (the HbA1c test will not pick this up).  

Sadly, the NHS simply can’t afford to pay for the blood glucose testing strips for everyone who would benefit.  This is why blood sugar testing at home tends to be discouraged in the UK unless someone is on insulin or on medication which puts them at risk of low blood sugar levels.  However, you don’t need a prescription to buy a blood glucose monitor or testing strips, which means that clients can choose to purchase these on their own if they wish. 

There are two blood sugar monitoring systems available:

1) Finger prick blood glucose monitoring

This is the least expensive and most familiar option.  Clients would need to prick their finger with a sharp lancet each time they want to know what their blood sugar level is.  The fact that this is a little painful often limits how frequently clients are willing to test and so we usually end up with less “data” to work with.

2) 24 hour continuous blood sugar monitoring (without any finger pricks)

There is only one monitor in the UK like this and that is the Abbott FreeStyle Libre blood glucose monitor.  The FreeStyle Libre is a painless sensor that sticks on your arm and transmits information on blood sugar levels by waving a meter or smart phone in front of the sensor.  The sensor automatically checks blood sugar levels every 15 minutes.  Up until a few weeks ago there was a supply issue with these meters, so sale was limited to people with Type 1 diabetes.  However, the supply issue has now been corrected and it is now available for anyone to purchase by clicking HERE.   Note: The NHS will only provide this monitor to clients with Type 1 diabetes, so other clients will need to pay for it themselves.

How blood sugar monitoring motivates clients

One of the main downsides to improving eating habits is that people can’t always “feel” the difference straight away and this can lead to reduced levels of motivation.  Self-monitoring of blood sugar levels is highly empowering, because clients can immediately see that what they are eating has a direct impact on their blood sugar levels and how they feel.  The blood sugar monitoring doesn’t have to go on long-term either — often just a few weeks will have the desired impact.

The reality is that everyone’s body responds differently to food.  While I can tell people how research has found different foods to affect blood sugar levels (called the glycemic index of food), in reality, we don’t know how someone’s body will respond until we actually check.  I don’t like guessing, so if there is a way to have tangible data on what is going on in someone’s body, that is always my preference.

If you have a client who would benefit from expert advice around blood sugar testing, interpreting the results and/or if they want education around how different foods affect blood sugar levels, then please get in touch with Sheri Taylor, Specialist Rehab Dietitian at 0121 384 7087 or info@specialistnutritionrehab.co.uk.  To receive articles like this one straight to your inbox, please sign up for my monthly newsletter below.