We all know that exercise is good for us but diabetes presents some challenges - blood sugar levels can drop low or rise unexpectedly during exercise, but don't be deterred! People with diabetes can achieve amazing things - US Olympic Swimmer Gary Hall Jnr and UK Rower Steve Redgrave both have diabetes. Zippora Karz, a member with the New York City Ballet, was diagnosed in the middle of her career at 21 and went on to be appointed soloist at 27. Closer to home, AFL footballer Dale 'The Flea' Weightman was also diagnosed in the middle of his career but it didn't stop him becoming a legend of the game. More recently, Nathan Bassett hasn't let type 1 stop him from becoming a player in the Crows Adelaide football team..

Dr. Sheri Colberg-Ochs, an Associate Professor of Exercise Science at Old Dominion University, author of the book The Diabetic Athlete, and a diabetic athlete herself, provides some useful information for managing diabetes around whichever exercise you may wish to do or continue doing.

• Regular exercise is the most important activity that you can do to slow the ageing process, manage your blood sugars, and stay healthy.
• The best way to deal with the multitude of variables is to learn your own responses to all of them by checking blood sugar levels before, during, and after exercise. 
• Intense exercise can cause a large increase in blood sugars due to the surge in glucose-raising hormones. 
• You may find that after training for several weeks, your blood glucose does not drop as significantly as it did when you first started training.
• Regular physical activity improves blood glucose control by increasing the body's sensitivity to insulin.

It is crucial to know when your insulins peak in order to determine your blood sugar response to exercise and your need for supplement carbohydrates

Dr Colberg-Ochs recently answered some people with diabetes' questions in an interview with About.com.

Jennifer asks: "Why does my blood sugar actually rise after my regular morning exercise session?"

Dr. Colberg-Ochs answers: Many things can affect your blood sugar response to exercise, and it is normal for intense exercise to actually cause a rise in blood sugars.

In all likelihood, both the time of day that you are exercising and what you are eating for breakfast are probably having a large effect on your sugars. Morning exercise is notorious for causing less of a drop in blood sugars, even when compared with the exact same type of exercise done later in the day. The reason for this is that after you fast overnight (not eating between dinner and breakfast), your body releases extra hormones to keep your blood sugars normal, particularly high levels of cortisol and growth hormone, and the livers in diabetic people often overproduce glucose overnight as well. These hormones, while working well to keep your blood sugars normal overnight, also make your insulin less effective, thereby creating an "insulin resistant" state in your body in the early AM. By eating breakfast, you 'break' your 'fast' and provide alternate fuels that allow the levels of these hormones to then drop. So, breakfast is important, but it is also the meal at which our bodies have the hardest time with carbohydrates causing a bigger increase in our blood sugars. You may want to stick with a lower carb breakfast, saving them for after your workout when your insulin action has improved. Also, you may want to experiment with exercising at different times of day to see the effect. If you do continue with your morning exercise, though, the temporary elevations in your blood sugar will be just that: temporary. If they begin persisting past an hour or two, though, then you will need to rethink your strategy."

Carl asks: "I want to exercise to decrease weight and become more healthy. However, I have found that my sugar level drops quickly when I exercise. This of course leads me to feel as if I need to eat, and in return for eating I feel I defeated the purpose of the exercise which was to burn calories and lose weight. Is this cycle avoidable? Or is the eating actually ok?"

Dr. Colberg-Ochs answers: If you're using exercise to try to lose weight, then it would definitely be better to minimize the additional eating. However, a few simple changes in your diet and/or medications could easily help you to break this cycle. If you are able to make changes to your regimen, then you should be able to correct this problem. If exercise is causing your blood sugar to drop, then you can either lower your insulin dosages (consult with your physician if you don't know how to do this on your own), or adjust your diet for exercise. When you know that you are going to exercise following a meal or snack, eat foods with more carbohydrates in them (but that have approximately the same calorie content as what you would have eaten otherwise). These carbs will then be available to your body during exercise and should help prevent any drops in blood sugar. If you still have to eat something afterwards to compensate, consume only quick-acting carbs that will quickly correct your 'low' feeling, like a glass of soft drink, or 5-6 dry biscuits, but that will add relatively few calories. Do not eat foods high in fat or protein as they will not quickly correct a low blood sugar!

General exercise guidelines for athletes with type 1 diabetes

From the American Diabetes Association and American College of Sports Medicine.

Metabolic control before exercise:

• Ingest carbohydrates if glucose levels are below 5.5 mMol/L.
• Avoid exercising if fasting glucose levels are more than 14mMol/L and ketosis is present, and use caution if glucose levels are greater than 17mMol/L and no ketosis is present.

Blood glucose monioring before and after exercise:

• Identify when changes in insulin or food intake are necessary.
• Learn the glycaemic response to different exercise conditions.

Food intake :

• Consume carbohydrate as needed to avoid hypoglycaemia.
• Keep carbohydrate-based foods readily available during and after exercise.

Further reading about Diabetes and Exercise

The Diabetic Athlete by Dr Sheri Colberg-Ochs is available on order via your local bookshop or by contacting Human Kinetics Publishers, phone 08 8277 1555 or visit www.humankinetics.com 

Diabetes Exercise and Sports Association (US-based): www.diabetes-exercise.org

Fact sheet from the Australian Institute of Sport: www.ais.org.au/nutrition/documents/FactDiabetes.pdf

Hypoactive - information about Type 1 diabetes and exercise, plus events that Australasian diabetics have entered, and inspiring individual achievements  www.hypoactive.org