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Secret #27: Make It Strenuous

Nov 6, 2007

Excerpted from 50 Secrets of the Longest Living People with Diabetes



By Sheri Colberg, Ph.D., FACSM




There are certain benefits to be had from doing more intense exercise that some old-timers have recognized. Increasing exercise intensity even briefly works for everyone. For instance, in one study, unfit men and women in their thirties and forties experienced major gains in their aerobic capacity by doing a total of only six to eight minutes of harder exercise a week.

Such results explain the sudden interest in the ROM – The 4-Minute CrossTrainer available in specialized gyms that requires you to work out for only four minutes at day, but at a near-maximal pace. Workouts like those, although strenuous, are not likely to improve your cardiovascular fitness as much as longer sessions of aerobic exercise can, but short, intense work does have its benefits. The same intensity principle applies to almost every kind of exercise you do, from walking to cycling to gardening. In fact, even competitive athletes generally plateau at a certain level of fitness and performance unless they do some version of this heavier “interval” training from time to time.
Dr. Dick Bernstein, a sixty-one-year diabetes survivor, says that regular, strenuous exercise is what has kept him looking younger and in better shape than most nondiabetic people his age (seventy-three years old). He exercises every night, but in a non-conventional way. “For resistance training, I do one set with the highest weight I can lift three to four times, and then I use lighter weights to take each set up to twenty repetitions total,” he says. For cardiovascular exercise, he says, “If you’re in proper cardiac shape, for which you should get tested first, start off easy, but then you should finally get your heart rate above your theoretical max, back off, work it back up, back off . . . as many times as you have time for.” He believes that this type of training conditions your heart to work fast, but to slow down to a normal pace quickly (which is, incidentally, a sign of higher levels of cardiovascular fitness). He recommends alternating cardio and upper-body training with lower-body training and other upper-body exercises. “Increasing your muscle mass decreases insulin resistance, which is essential for all type 2s,” he explains. “For type 1s, exercise can sometimes complicate diabetes treatment, but is essential for health benefits.”

Dr. Sheri Colberg, being an exercise physiologist who specializes in diabetes and exercise, has some additional suggestions for gaining the most benefits from your workouts. A research study in the July 2006 issue of Diabetes Care tested out the exact type of training regimen she usually recommends. In that study, people with type 2 diabetes already walking over 10,000 steps a day began a program called “Pick Up the Pace,” or PUP. It still involved walking, but at increased speeds. Once they measured their usual walking speed (in steps taken per minute measured with a pedometer), they were asked to begin walking for 30 minutes, three times a week, at a pace that was only 10 percent higher than normal (e.g., a usual pace of ninety steps per minute would be upped to about 100 instead). Twelve weeks of PUP training for ninety minutes a week additionally increased their fitness without requiring them to take any extra steps.

Thus, to get the greatest health and diabetes benefits from your aerobic exercise, keep the PUP study in mind. During any activity, you can simply increase the intensity of your exercise for short periods of time (so-called “interval training”) to gain more from it. To start with, when you’re walking, speed up slightly for a short distance (such as between two light poles or mailboxes) before slowing back down to your original pace. During the course of your walk, continue to include these short, faster intervals occasionally, and as you are able to, lengthen them out to last two to five minutes each (or even up to thirty minutes, like was done in the PUP study). Not only will you become more fit and use up extra calories using this technique, but you also will likely feel more tired when you finish your walk (which is actually a good thing). Over the course of several weeks, you may even find that your general walking speed has increased due to the extra conditioning from your interspersed bouts of faster walking.

Also remember, though, that doing intense exercise may actually cause a rise in your blood glucose levels (which is usually only temporary in type 2s, but that may require some additional insulin to bring down in insulin users). For example, if you have type 2 diabetes and you do ten minutes of strenuous aerobic or resistance training, your blood glucose could possibly rise from a level like 130 mg/dl to 165 or higher. After an hour or two at most, your blood sugars will return to the level where they started, if not lower. It’s due to the same release of glucose-raising hormones (like adrenaline) that type 1 diabetic swimmer Gary Hall, Jr., often sees his blood sugars rise from 100 mg/dl to 300 from a 21-second all-out sprint down the length of a 50-meter (Olympic size) swimming pool during competitions. Since he doesn’t make his own insulin, though, he has to inject a couple units of rapid-acting insulin to bring his levels back down to normal. If you do an intense workout, one trick to try to counteract this effect is to do ten to twenty minutes of easier aerobic exercise afterward, which will have a glucose-lowering effect rather than a glucose-raising one.

On the other hand, an interesting recent study showed that if you do a short sprint (e.g., ten seconds) at the end of a moderate aerobic workout, your blood sugars will remain more stable (without dropping) for longer following the activity. The study only followed the first two hours, but likely the effect would be lost shortly after that. Accordingly, Dr. Colberg now frequently advises people who are getting low blood sugar during exercise (but who know that they don’t have high levels of insulin in their blood from a recent injection or bolus) to do a short sprint to raise their sugars back into a normal range and prevent hypoglycemia. For her, it works great!


Sign up for the newly-launched DIABETES "Fit Brain, Fit Body!" fitness/lifestyle programs or for 5 free Healthy Living Reports at www.lifelongexercise.com, and access more articles and information at www.shericolberg.com. If you need tips for getting safely started on an exercise program, check out The 7 Step Diabetes Fitness Plan. For people with any type of diabetes who are already more active, consult the Diabetic Athlete’s Handbook.

Click here for a full list of all of Sheri Colberg’s articles on fitness and diabetes.

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