When people without diabetes are physically active, their blood glucose levels are finely regulated by their body. There is a surge of extra hormones, notably adrenalin, which causes the body to make extra glucose to fuel muscles and, when this happens, there is an automatic mechanism in the body which shuts off the flow of insulin.
Hypoglycemia
People with Type 1 diabetes don’t have the automatic ‘fine tuning’. This means physical activity may cause a hypo as your muscles use energy.
To reduce the chances of this, bear in mind the following:
- injection sites should be away from the limbs which will be used during activity (eg, the thigh if playing football)
- fast-acting carbohydrate snacks should be at hand while being active
- pre- and post-activity blood glucose monitoring is essential
- delayed hypos, up to 36 hours later, can occur as the muscles refuel after activity.
- If you’re doing a more strenuous activity or one for longer than an hour, marathon running, for example, you’ll need to eat extra carbohydrate while you are active.
Hyperglycemia
As well as causing hypos, activity can actually cause high blood glucose levels – hyperglycaemia.
This could happen if you haven’t injected enough insulin, because of the dominating effect of adrenalin. Having hyperglycaemia can cause you to develop ketones, so check for these, just in case.
Do not do any physical activity if your blood glucose levels are above 14mmol/l or if you have ketones in your urine.
To sum up
You’ve got to consider:
- timing
- your last meal
- blood testing before and after
- glucose tablets
- your insulin.
Do I need to do anything before I start increasing my activity levels?
Before you start any activity regime, you need to check with your GP.
If you’re trying to lose weight or starting to take vigorous activity regularly, you may need to change your dose of insulin, or test your blood glucose levels more often; or it could be that certain types of activity aren’t suitable for you at the moment because of other health conditions.
There’ll probably be a fair amount of trial and error when you start to try and balance your insulin and food with activity.