What You Really Need to Know about Exercise and Diabetes. By Sheri Colberg, Ph.D.

 Diabetes Living Today presents an “exclusive guest post” written by Dr. Sheri Colberg for our reader’s:


What You Really Need to Know about Exercise and Diabetes

By Sheri Colberg, Ph.D.

Even though I have personally been living with diabetes since I was four years old (in 1968), I knew even back then-more than a decade before the era of home blood glucose monitoring began-that exercise did good things for my blood sugars.  How could I tell without a blood glucose meter?  Mainly I knew because being active always made me feel better, physically and emotionally, in ways that nothing else could.  In fact, as I went through my teenage years without any way to know what my blood sugars were, exercising regularly gave me the only sense of control that I had over my diabetes.  There are some things that I know now about exercise that I wish someone had told me years ago.  Luckily, times have changed, and you have access to information now about exercise and diabetes (any type) that I did not.

For starters, did you know that exercise can virtually erase your blood sugar mistakes?  I knew it helped me, but it wasn’t until I got my first monitor in the mid-1980s that I found out how much.  Why?  Exercise acts as an extra dose of insulin by getting the sugar out of your blood and into your muscles without insulin (through an insulin-independent mechanism related to muscle contractions themselves).  When you’re not being active, your body needs insulin to stimulate that uptake.  Being regularly active makes your muscles more sensitive to any insulin in your body as well, so it takes less to get the job done.  What better way to help erase a little overeating of carbs (or a slight lack of insulin or insulin resistance) than a moderate dose of exercise to lower your blood sugar?

Something else I wish I’d known is that exercise doesn’t always make your blood sugar come down, at least not right away.  When you do really intense exercise, the glucose-raising hormones that your body releases (like adrenaline and glucagon) can actually raise your blood sugar somewhat instead, albeit usually only temporarily.  This phenomenon in true for people with type 1, type 1.5, type 2, and gestational diabetes, and even for anyone without diabetes.  However, even if a workout raises it in the short run, over a longer period of time (2-3 hours), the residual effects of the exercise will bring your blood sugar back down while you’re replacing the carbs in your muscles that you used.  If you take insulin, be careful to take less than normal to correct a post-workout high or your blood sugar will likely be crashing low a few hours later.  If you don’t take insulin, just give it some time to come back down or do a cool-down of less intense exercise (like less-than-brisk walking) to help bring it back to normal.

Another thing to know is that how much muscle you have really makes a big difference.  Exercise helps you build and retain your muscle mass, which is the main place you store carbs after you eat them.  Almost any type of exercise uses up some of those stores-known as muscle glycogen-but if you don’t exercise regularly, your muscles remain packed with it.  There is a maximal amount that fits in muscles, which is why building up your muscle mass helps with being able to handle the carbs you eat more effectively.  Your liver stores some glucose as glycogen, but not that much relative to your muscles’ total storage capacity.  Thus, being sedentary ensures that no amount of insulin is going to be able stimulate more blood glucose uptake into your muscles.  Without regular exercise to use up some of that glycogen, you really have nowhere to store carbs, so your blood sugars go up and some of the excess gets turned into body fat instead (since still works to stimulate fat storage even when your muscles are insulin resistant).  You can’t lose body fat if your insulin levels are high (or you take large doses).  Having more muscle-which is an insulin sensitive body tissue-is definitely a good thing, but something you have to work at since aging causes you to lose the muscle fibers you don’t use regularly.  Doing resistance or weight training is critical to maintaining the muscle mass you have and offsetting the effects of getting older as much as possible.

I have an even longer list of all the things I wish I had known about exercise and diabetes, but let me share just a few more tidbits with you to whet your appetite for more.  Exercise is probably the best way to control emotional stress and to stave off depression-far better than antidepressant medications and with no bad side-effects!  What’s more, exercise naturally bestows your body with antioxidant effect, which is why regular exercisers are less likely to develop most types of cancer; why they generally feel and act younger than their chronological age; why they’re less likely to even get a cold if doing moderate amounts of regular exercise; and why exercise is about the best medicine that there is for so many other health conditions (so don’t forget to take your daily dose).  Finally, there are many different ways to exercise, including standing up more, taking extra steps during the day, fidgeting, and just generally being on the move whenever and wherever possible.  Knowing that hopefully takes away all of your excuses for not being more active.  If you can’t get in a “planned” workout on any given day, you can certainly add in more steps or other activity all day long instead (or do it in addition to your usual exercise).  Every bit of movement you do during the day counts, so fidget away!

If you need motivation or tips for getting started on an exercise program, check out my book entitled The 7 Step Diabetes Fitness Plan.  For people with any type of diabetes who are already more active but want more in-depth information, my latest book released in November 2008, Diabetic Athlete’s Handbook, is for you; it’s packed with good information for type 1 and type 2 exercisers, along with real-life athlete examples, athlete profiles, and over 100 sports and recreational activities.  For inspiration about living long and well with diabetes, consider reading 50 Secrets of the Longest Living People with Diabetes.  For all sorts of other tips on exercise, fitness, diabetes, nutrition, and more, please visit my Web site and exercise blog at www.shericolberg.com

Photo Above: Dr. Sheri Colberg