Exercising with diabetes.

? I'm 62, 4' 10", 95 pounds. I have been fighting diabetes for three years without medication, and have been able to consistently keep my morning readings below 110. However, I've noticed after high-intensity tennis or running, my blood sugar count is often in the 200 range. An hour or so later, the level is back down to around 120. My tennis games are very competitive, and I play four or five times a week. Am I harming my body? In addition to tennis, I try to speedwalk or jog 20 miles a week, and I've noticed my blood sugar level does not spike on days when I just speedwalk. By comparison, my last run was a 5K at 9:15 mile pace, and my blood sugar level was 240 ten minutes after the race. My diet consists mainly of vegetables, oil and protein.

Susan Stevens, Los Angeles, CA

I have type 1 diabetes and have managed it with an insulin pump for 14 years. I've completed seven marathons since being diagnosed in 1991. I emphatically urge you to continue your exercise regimen--the benefits, both physical and psychological, are just too great to give up. That said, please know that it is very common for diabetics to progress over time from managing their disease with diet and exercise, then to taking one or more oral medications, and finally to insulin. It's good that you test regularly. I would keep your doctor informed about your blood glucose response to the vigorous workouts, as he/she may one day feel the need to prescribe medication to help you manage; this is not a bad thing. You should continue your workouts. Your body's response to them is not unusual, and may be related to catecholamine release. This is a stress hormone that causes the liver to produce glucose. You seem to follow a low-carb diet. Your age at diagnosis suggests that you may have overt type 2 diabetes, which is well controlled with diet and exercise. Remember, however, that diabetes can be a progressive disease and so medications may become necessary down the line.

Kevin Foley, MS, Baltimore, MD

Exercise typically lowers blood sugar level in type 2 diabetics during the event and for one to two days following, which is one reason why exercise is recommended for diabetics. Therefore, I suspect you are not as well controlled as you think you are. Check your glycohemoglobin with your doctor. This is a measure of long-term blood glucose control. It is reflective of the last three months of blood sugar levels, and more meaningful than individual blood sugars. I think you may need some type of once-a-day medicine that will make you more sensitive to the insulin your body makes. Another consideration is how much glucose loading you are doing in the meals before (and during) exercise. On a side note, I recommend having a stress test or heart scan, since diabetes is a major risk factor for coronary artery disease, which is often asymptomatic.

Peter Mendel, MD, Woodbridge, VA

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