The topic of exercise and diabetes has been in press since the mid 1920’s when studies revealed that exercise has an insulin-like effect on blood sugars. Reports over the past 70 years have concentrated mostly on the physiological action of exercise on metabolism and muscle, and not so much in constructing the best way of exercising to improve overall health.
None the less, if most persons with diabetes (especially type 2 adult onset) would engage in a walking program every day for 15-30 minutes, they could significantly reduce their chances of having diabetes complications that are associated with the disease over time.
A recent report in a fitness publication revealed the average diabetic’s distane for exercise. A survey of 1,000 diabetics from the Joslin Clinic in Boston revealed that over 75% of them would rather take daily insulin injections for their control than perform regular exercise. That about sums it up in terms of their preference – but how did this scenario happen in the first place? Well, as it turns out, most diabetes physician caution their patients against exercise if their blood glucose levels are too high. It seems that if the sugar levels exceed a certain blood volume, then ketoacidosis could result if exercise proceds.
In my tenure as a diabetes and exercise researcher, I never could find the exact study that showed blood glucose levels actually increased if they were at a certain level (the ADA used the figure of 250 mg/dl). As a matter of fact, in my own studies, I found that as persons increased their fitness levels (say, after 2-3 weeks of exercise) their blood sugars would drop, even if they exceeded that 250 mg/dl amount pre-exercise. However, I never had any collaborating research to back up my work until last year.
One study in 1996 has come to my attention that deserves mention for all of theose health professionals who caution against exercise if blood glucose levels exceed that 250 mg/dl number. In a presentation at the 1996 American Association of Diabetes Educators national meeting in New Orleans, LA, Robert Hanisch and Ann Snyder presented information that will dramatically change the way exercise programs are applied to diabetics. In a study of over 1,000 consecutive exercise sessions, the authors attempted to identify if the classic information given to exercise instructors not to perform conditioning on a diabetic with blood glucose levels over 250 mg/dl was prudent advice. Over 300 exercise sessions were performed on patients with pre-exercise BGL’s over 240 mg/dl. However, only 4 sessions resulted in an increase in BG. The mean increase for these 4 sessions was 23.5 mg/dl. Conversely, the mean change in BG of the remaining 311 sessions was a decrease of 52.5 mg/dl. The mean decrease in type 1 subjects (n=133) was 61.3 mg/dl. The mean decrease in type 2 subjects was 46 mg/dl (n=178).
For 98.7% of this group, the advice to delay exercise due to a possible deterioration in the metabolic control post-exercise would have been incorrect. Therefore, the commonly provided advice regarding acceptable pre-exercise BG levels for a person with diabetes should be reconsidered.
My own experience with diabetes mirrors this advice. I tell trainers who may not be familiar with diabetes and exercise that conditioning sessions should be “blood glucose dependent” – meaning that higher levels constitute a more vigorous and longer training session (more glucose to burn). Lower levels (under 120 mg/dl) constitute a less vigorous session for less time. If these principles are followed, emergencies will be highly unlikely.
Exercise has been shown to be effective in preventing the occurance of diabetes in persons who are at high risk for contracting the disease. Studies also show that exercise may be performed with persons who have diabetes complications (although not at severe levels), and that persons can perform intense exercise and even sports competition with the disease without suffering undo problems.
With over 70 years worth of information on the benefits of exercise for diabetic persons, it should be part of EVERY diabetic persons’ medical plan to include daily moderate exercise for their diabetes control, weight management, muscle strength, aerobic fitness, and self esteem. In this instance, a little exercise goes a LONG way to improving health.
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