In the last post we looked at the two types of diabetes and the differences between them. Perhaps the most obvious difference is that people with Type 1 diabetes must rely on insulin injections to control their blood sugar levels. This can be tricky enough on a normal day. Get the insulin dose too high, and too much glucose (sugar) will be absorbed from the blood into cells, leading to low blood sugar levels (hypoglycaemia). Get the dose of insulin too low, and not enough of the sugar will be absorbed by muscle and liver cells, leading to high blood sugar levels (hyperglycemia).
This becomes more complicated when you add exercise to the mix. In non diabetics, the release of hormones during exercise signals the liver to release more glucose into the blood, so it can be used to fuel working muscles. At the same time, these working muscle cells become more sensitive to the action of insulin, so they absorb more glucose with a smaller amount of insulin. To compensate for this, they body releases less insulin. The longer and more intense the exercise, the more sensitive muscle cells become, so the lower insulin levels fall.
However, a Type 1 diabetic controls their insulin levels using injections. The cells still become more sensitive to the action of insulin with exercise, so they will need to inject less insulin on a day they plan to exercise. How much less depends on the type and duration of the exercise, and the diabetic’s own body. This means experimenting with different types of exercise and doses of insulin, and risking hyper or hypo-glycemia. What’s more, blood sugar levels can continue to fluctuate for hours after exercise as the body restocks muscle glycogen stores.
Sadly this complexity has led many health care professionals over the years to recommend Type 1 diabetics avoid all exercise. The problem is, most diabetics do not die of diabetes – they die of cardiovascular disease and cancer like everyone else. Diseases which we know are prevented, at least in part, by regular exercise.
So it is worth the time and effort to determine how a particular diabetic reacts to exercise. A continuous blood glucose monitoring device can make all of this much easier, and save the diabetic from having to stop exercising every 10 minutes to check their blood sugar. After a few exercise sessions they should see a trends in how their body reacts and be able to adjust their insulin accordingly.
The most likely problem is a hypoglycaemic episode (low blood sugar). The early symptoms of low blood sugar levels are shakiness, dizziness, sweating, hunger, headache, irritability or moodiness, and anxiety or nervousness. Unfortunately, some of these are also symptoms of exercise, especially in a competition situation, so it can be hard for diabetics to diagnose low blood sugar without testing. With practice, most become adept at identifying when they “have gone hypo”. The treatment is relatively straightforward – a sugary snack. And most sports drinks and gels are ideal as they are designed to provide easy to digest, quick sugars.
Because of the risk of hypoglycaemia, Type 1 diabetics should never exercise alone. Having a workout partner or coach who can help should they have an episode is an essential safety precaution. It can also give the diabetic the confidence to get out there and give exercise a go.
With proper precautions and medical monitoring, there is no reason why Type 1 diabetics should avoid exercise. It may not always go smoothly, but the long-term health benefits and joy of sport make it all worthwhile.