I had such great feedback on my last blog ‘Blood Pressure for Runners’ that I’ve decided to stick with the ‘medicine made easy’ theme for this blog too. I want to to look at the subject of blood sugar. Like blood pressure this can seem a confusing topic; hypoglycaemia, hyperglycaemia, diabetes, insulin etc etc. What does it all mean and why is it important, even for the most active of us?
What is blood sugar?
When we’re talking about blood sugar we’re really talking about glucose. All of our cells need glucose to function, it’s their main source of energy. When we eat carbohydrate (of any sort) our body breaks it down into smaller molecules and glucose is one of these.
Our body works hard to keep our glucose level nice and even. Generally our systems prefer to be in a ‘steady state’ with not too many ups and downs of anything. Obviously our glucose level varies a bit, especially when we eat, but before we eat a normal blood glucose is between 4 and 7 mmol/L.
Hypoglycaemia and hyperglycaemia
Fancy words but break them down and it’s easy to understand and remember what they mean. Hypo means low, glyc is short for sugar and aemia means in the blood. So hypoglycaemia means low sugar in the blood and hyperglycaemia means high sugar in the blood. Easy!
Hypoglycaemia can happen to all of us. Our body wants glucose badly so it makes us feel very unpleasant. You might have experienced the jitters or shakes, irritability, nausea or headache. It’s quickly resolved by eating or drinking some carbohydrate. As runners this can happen if we’ve not taken enough food on board to fuel a hard run or simply gone way too long in between eating. It’s easily avoidable, treatable and is nothing to worry about. If hypoglycaemia is happening at other times then you need to see your GP as there are a few other conditions that can cause it. Remember alcohol can cause hypoglycaemia too and falling blood glucose levels can reach dangerous levels if you’re too drunk to do anything about it.
Having ‘hypos’ is not a sign of diabetes. It’s a common misconception; patients often come to me worried they might have diabetes because they keep going hypo. People with diabetes can have hypos but it’s because of their treatment and not because of their condition. Diabetics have too much glucose circulating in their blood – hyperglyacaemia. If they start a treatment that might cause hypoglycaemia then they’re carefully educated about the dangers before they commence it.
When we eat something and our blood glucose levels rise then a hormone called insulin is released from a gland called the pancreas. (The pancreas sits just close to our stomach). Insulin causes glucose to move from our blood and into cells. This then lowers the blood glucose level. When our cells have enough glucose then any extra is stored as glycogen in our muscles and liver.
People with diabetes have less insulin. Either they aren’t making enough or the body doesn’t respond properly to the insulin that’s there, we call this insulin resistance. So, with a lack of insulin, less glucose moves into cells, more remains in the blood stream and you get hyperglycaemia.
Hyperglycaemia for a prolonged length of time can damage the body. It gives you five times the risk of heart disease and stroke. It can cause blindness by damaging the blood vessels in your eyes. It leads to kidney damage and failure. It damages your nerves leading to numbness and problems with your feet. It might cause difficulties with erections and it causes problems in pregnancy too. The list is endless….
Symptoms that might indicate a high blood glucose include: feeling thirsty and having a dry mouth, passing lots of urine especially during the night, feeling very tired and getting lots of skin infections such as boils or thrush.
We think about 1 in 17 people in the UK have Type 2 diabetes (the commonest type of diabetes) many are unaware they have it. Many more are at high risk of developing it. If you’re concerned you may have diabetes then you can speak to your practice nurse to arrange a blood test.
There are several blood tests that can confirm diabetes. A random blood glucose (above 11.0 mmol/L), a fasting blood glucose (above 7.0 mmol/L), a glucose tolerance test (above 11.0 mmol/L 2 hours after the test) and a test called HbA1c. The latter is being used more and more now to diagnose and monitor diabetes. It’s a clever test because it doesn’t just give a snap shot of the glucose level at the time the test was taken, it gives an idea of what it’s been over the last 8 to 12 weeks. It’s measured in % and an HbA1c of over 6.5% is classed as diabetic. Importantly it helps us to detect those who are at high risk of developing diabetes (HbA1c of 6.0% to 6.4%). This is a huge group of people and with lots of encouragement and lifestyle changes they can often prevent their condition developing into diabetes.
Steps to help maintain a healthy blood sugar
We can’t change our age, our genetics or our ethnicity (all factors affecting our risk of diabetes) but let’s finish on a positive; what can we do to look after our blood sugar levels?
1) Eat a sensible healthy diet.
2) Take regular exercise (not an issue for most runners).
3) Avoid long periods of sitting and break up sedentary periods with a couple of minutes of walking. Very important for all of us, even if we do a 30 minute run in the evening when we get home.
4) Use the above tips to help us achieve and maintain a healthy weight.
Diabetes is a hugely important condition because of the sheer numbers of people affected and the health problems it causes. Taking simple steps to improve lifestyle and to generally move more can stop it developing and help in the treatment for those that have it. If you’re doing a great job looking after your own blood sugar then why not help a friend get active to reduce theirs.