Fitness training: ADA recommends

The American Diabetes Association gives good advice on how to avoid low blood glucose (hypoglycemia) during exercise.

Blood glucose measurement

Timing: Exercise 1 to 3 hours after a meal. Blood glucose is at its highest.

Insulin peak: Don't exercise when your insulin injection is peaking. If using rapid-acting or regular insulin, this means avoiding sports in the first 1 to 2 hours after injection.

Adam Morrison

Insulin absorption: Exercise increases blood flow, which speeds up how fast insulin works.

Duration and intensity: If your activity is moderate to high intensity, or if it's moderate and long, consider decreasing the insulin dose that's working while you exercise.

Blood glucose response: Build up knowledge and experience of how your blood glucose responds to different types of exercise. Monitor blood glucose (BG) often: before, during, and after activity.

Insulin injection

BG stable or dropping: If you are going to be doing demanding exercise for a long time, check your BG 1 hour before you begin, then check 30 minutes before to find out if your blood glucose is stable or falling.

Eating during exercise: you might need to eat during or after sporting activity if you work out hard, or if it lasts longer than an hour.

Length of BG reaction: You can have a blood glucose reaction up to 24 hours after exercise, depending on how hard or long your workout.


Follow links to the top stories simmering on typ1diabetes

1: Missy Foy: T1DM & ultramarathon racing

2: Adam Morrison's match with DKA

3: Soccer star collapses with hypoglycemia

4: Team Type 1 rides for victory

5: Fitness coaching for T1DM

6: Horrors of insulin shock therapy

7: Halle Berry's type 1/ type 2 confusion

8: Milestones in diabetes treatment

9: My young child has T1DM

10: Treating ketoacidosis in hospital


Clear, accurate answers to your diabetes questions

1: What is type 1 diabetes (T1DM)?

2: Why is insulin important in the body?

3: What does glucose do in the body?

4: When was insulin invented?

5: Why is low blood sugar a problem?

6: Why is high blood sugar a problem?

7: What causes low blood sugar?

8: What causes high blood sugar

9: Is there a cure for type 1 diabetes?

10: Explain diabetes to a young kid

Diabetes advice

By Alan L. Rubin MD, Type 1 Diabetes For Dummies gives clear, easy-to-understand explanations and advice on living with type 1 diabetes.

This is an excellent choice for busy parents of kids with type one diabetes.

Standard text

By Richard K. Bernstein, Dr. Bernstein's Diabetes Solution: The Complete Guide to Achieving Normal Blood Sugars is the standard text on living with diabetes, newly revised and updated with all the latest scientific findings. Accurate blood sugar monitoring is the key to successful diabetes management.

Exercise and fitness with T1DM

Running on beach

VISIT our sister sites and pages:

Courage to run

How to start

Run at 40+

Too busy?

Running shoes

Exercise and fitness training are good for everybody, including people with T1DM. But in addition to the demands of training, type ones must constantly monitor blood sugar levels to prevent deep lows and excessive highs.

T1DM does not place impossible barriers in the path of athletic excellence. Ultra-runner Missy Foy, pro-cyclist Phil Southerland, pro basketball player Adam Morrison, and soccer pro Par Zetterberg are all elite athletes with type 1 diabetes.

Pro athletes

Not so many years ago, they would probably have been discouraged from pursuing a demanding career in pro sports. It would have been considered way to difficult to maintain healthy blood sugar levels while training at elite levels.

Ultra marathon runner Missy Foy explains, Doctors thought it would be too difficult, too stressful, to balance insulin and the intensity of training.

All that has changed. Dr. Larry Deeb, president of medicine and science at the American Diabetes Association, says, I want kids with diabetes to be empowered to take care of themselves and to know and believe that there are no impediments before them. If patients want to run a marathon, I would encourage them.

Blood sugar management

User friendly blood sugar meters and small, convenient insulin pumps have made it much easier to be an elite athlete with T1DM. But there's still the need to keep an eagle eye on blood glucose and insulin levels.

As pro cyclist Phil Southerland explains, The tough part is, if we have too much insulin on board before the race, we’ll bonk immediately. If our blood sugar is too high we won’t perform at our best, and if it’s too low we won’t perform at all.

Southerland checks his blood sugar 18 to 25 times a day. He says, We are the C.E.O.’s of our own bodies and we don’t get a break from them.

Regular routines and attention to detail are essential to success. David Weingard, an Ironman competitor, says, I figured out what it's like to go in the pool at exactly the time the race would start, to test myself during the swim, then to come out and see how much insulin I needed to take. I learned what my routine would be every single hour.

Glucose-insulin dance

Glucose and insulin work in tandem in the body, so it's not easy to talk about one without mentioning the other. But it's helpful to treat them separately and explain what each one does in the body during exercise.


Usually when talking about diabetes, it's all about glucose making its way from food into the bloodstream.

But glucose is also found in muscles, where it is stored as glycogen ready for use as energy.

When you start to exercise, your body uses the glucose stored in your muscles and liver. As these stores runs low, your body uses glucose from your blood, which causes a drop in blood glucose.

After exercise, the body replenishes glucose stores in the muscles and liver. This can further lower blood glucose, even hours after you have stopped physical activity.

A person with T1DM who exercises in the evening can become hypoglycemic while they sleep. That's why it's good to monitor blood glucose before and after exercise.


The body absorbs insulin differently from day to day. Add to that the fact that exercise affects insulin absorption by increasing blood flow through the body. This speeds up the time it takes an insulin injection to work.

Injecting into an arm or leg that is directly involved in the exercise speeds up absorption even more.

All this makes it essential to keep monitoring blood glucose levels before, during, and after exercise.

Highs and lows

You might think that exercise is only likely to lead to low blood glucose (hypoglycemia) but it can result in high blood glucose too.

If you exercise vigorously, nerves signal to the liver to release stored glucose, which can result in a rapid rise in blood glucose.

This can occur with moderate exercise too if your insulin levels are low. As a result, ketones can be produced, resulting in ketoacidosis.

During gentle to moderate exercise that doesn't last too long, the opposite is likely to happen: blood sugar will fall during and after exercise, which means a risk of hypoglycemia.

Snack during workout

You might need to eat a snack during exercise. The American Diabetes Association recommends snacks that are low in fat with 15 to 30 grams of carbs.

During very demanding exercise, you might have to snack twice. It's a fine balancing act based on what you ate before exercise, how demanding the workout is, and what your insulin levels are.

Rapid insulin

It's not recommended to exercise within 1 to 2 hours of taking rapid-acting insulin. The insulin will be peaking, exposing you to the risk of hypoglycemia.

If you think a low blood glucose reaction is on its way, stop exercising at once. Do not take any risks.

Keep some glucose handy in case this happens. If you drink soda or fruit juice, it will provide glucose and much-needed fluids.

By David Hay Jones

(Fact-checking: This information has been double-checked against The American Diabetes Association recommendations in its American Diabetes Association Complete Guide to Diabetes: The Ultimate Home Reference from the Diabetes Experts and Alan L. Rubin's Type 1 Diabetes For Dummies, both of which are excellent resources.) Thanks also to the New York Times.