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My experience wearing a continuous blood glucose monitor

Published by Cheryl Mussatto, MS, RD, LD on Feb 15, 2017

Working as a clinical registered dietitian at an endocrinology clinic always brings new challenges and opportunities of interacting with patients. Individuals with diabetes need dietitians’ expertise and advice to help better manage blood glucose levels gaining optimal control of their disease to reduce and prevent health complications. And what better way to do this than to step into the shoes to experience what someone with diabetes goes through.

A while back, my supervisor, Barbara, at the clinic asked if I would be willing to wear a continuous glucose monitor (CGM) for a few days. I do not have diabetes but the purpose was to one, give me the perspective and experience of what someone with diabetes has when wearing such a device. Secondly, actually wearing one would provide me the opportunity to have a better understanding of how a CGM works.

A CGM is a device for people with diabetes to measure their glucose levels in real-time throughout the day and night. It provides a more complete picture of glucose levels which can lead to better blood glucose control and treatment decisions. This device does not deliver insulin into a person as it only monitors a person’s blood glucose levels.

For those of us without diabetes, our body naturally tracks our glucose levels all hours of the day and night making sure the right amount of insulin, a hormone released by the pancreas, is provided at the right time. If our blood glucose goes too high (hyperglycemia), the pancreas will release insulin to bring the glucose levels back down to a normal range. If our blood glucose goes too low (hypoglycemia), the pancreas releases another hormone called glucagon that stimulates the liver to release glycogen which is stored glucose to bring the blood glucose levels back up into a normal range.

I agreed to wear a CGM and here is a summary of what my experience was like:

Wednesday – Barbara, who is also a dietitian, inserted the device with an applicator which looks basically like a shot. It made me a little nervous but I thought, hey, I can do this. Typically the device is inserted into fatty areas of the body such as the abdomen, love handles on the back, or the back of the upper arm. I chose my abdomen for placement which is the most common area of placement.

Before inserting it, Barbara showed me the tiny, extremely thin electrode attached to a glucose sensor that would be placed directly under my skin to measure glucose levels in my tissue fluid. It appeared to be less than an inch in length and looked harmless.

The initial insertion hurt slightly more than a shot, but like I said the actual electrode is quite thin and small and once it was in, I didn’t feel a thing. In fact, 99% of the time I wore it, I didn’t feel it at all – no itching, pain, redness or swelling occurred – very comfortable. The actual sensor sitting on top of the electrode was small enough to be easily covered up with clothing and no one would know you are wearing one.

After insertion, a small sticky patch is used to firmly hold it in place for up to 7 days before it needs to be removed and replaced with a new insertion of a CGM.

Barbara then explained in detail how to use the second device that goes along with the CGM sensor called a CGM transmitter. A CGM transmitter receives information from the glucose sensor inserted in my abdomen. The CGM transmitter is a small lightweight device – smaller than an Iphone 7 – that was not attached to the CGM sensor on my abdomen but it needed to be within a 20 foot range of the CGM sensor in order to record glucose readings which were done every 5 minutes. In order to have as a continuous amount of readings as possible, I chose to primarily keep the transmitter on me about 95% of the time, except for when I slept which then I placed the transmitter next to me on my nightstand.

To get the most accurate blood glucose readings, the transmitter needed to be calibrated twice a day, 12 hours a part. Therefore, I was also sent home with a blood glucose meter to prick my finger for a drop of blood to perform this task. Each time this was done, I plugged in the reading or number from the blood glucose meter into the CGM transmitter.

No matter where the CGM sensors are placed on the body, they can be worn when taking a bath, shower, swimming, exercise, sleep, or while doing just about anything.

Once I was home, I found myself checking my blood glucose about every 5 minutes! That first evening it seemed my glucose levels were all over the place – up and down. In fact, after eating dinner, it spiked above the 180 mg/dl level Barbara had set as the “high” for me. The transmitter sent out a buzzing sound warning me my blood glucose was too high. A warning signal is used to alert a person if their blood glucose is too high or too low, to help avoid wide swings in blood sugar that could spell trouble.

That first evening was the only time I got “buzzed” for my blood glucose being above 180 mg/dl – it never did go below what Barbara had set for a too low blood sugar of 70 mg/dl. The transmitter was apparently still adjusting to my blood glucose readings on that first day after being inserted.

Thursday – This day was uneventful. I took my blood sugar reading at 5:30 am and again at 5:30 pm. It was very interesting to watch every time soon after eating food the reading on the transmitter rise. Mine always seemed to peak at around one hour after a meal and then had a gradual decline afterwards.

Friday – I took my blood glucose at approximately 5:30 am which read 114 mg/dl. My CGM transmitter however read 128 mg/dl. Every time I went to calibrate the transmitter, the reading I got from pricking my finger was always different from the reading on the transmitter.

However, I remembered Barbara telling me not to expect the CGM readings to match the transmitter readings as there is up to a 5 second delay between readings and the fact that our blood glucose fluctuates each and every second of the day.

Saturday – I decided to do an experiment to test out how exercise affects blood glucose. At 5:30 am I tested my blood sugar on the blood glucose monitor and it read 119 mg/dl whereas the reading on the transmitter read 123 mg/dl.

I ate breakfast first – at 5:45 I checked my blood sugar according to what the transmitter said which was 109 mg/dl. I had ½ cup oatmeal, ½ cup orange juice, 1 ½ scrambled eggs, ¼ cup blueberries and about 2 teaspoons of cinnamon mixed with sugar for my oatmeal – I like it a little bit sweet. After eating, I walked on my treadmill for 30 minutes. I checked my blood glucose on the transmitter and it read 112 mg/dl. Two hours later after eating breakfast at 7:45 am, my blood sugar was 93 mg/dl. That tells me that exercise really does make a big difference in helping to keep blood glucose levels in check preventing them from getting too high.

Sunday – This time I walked on the treadmill before breakfast. I took my blood glucose reading before exercising which was 115 mg/dl. Thirty minutes later, when I was done, I checked my blood glucose again and it had gone down to 108 mg/dl. Otherwise, it was an uneventful day with my readings responding accordingly to what I ate and how much I moved or exercised during the day.

Monday – I had the device removed on this day when I went back to work. The tape was removed and then the glucose sensor was simply pulled out with no pain whatsoever.

What I learned from wearing a CGM

  • Portions sizes really matter. If you’re going to have foods such as pasta, potatoes, corn, etc., keep the portion sizes small. These “starchy” foods can flood our blood vessels with too much glucose making it harder for our pancreas to keep up supplying sufficient insulin removing the glucose from the bloodstream into the cells of our body.

  • Consistency and regularly timed meals are important. Eat about the same amount at each meal or snack to avoid wide swings in blood glucose levels.

  • If you’re going to eat a food composed of a lot of sugar, such as a cookie, to keep blood sugar levels from spiking too high, eat it with a meal composed of high fiber/protein foods (veggies, fruits, nuts, whole grains) to slow down digestion keeping blood glucose levels from rising higher than it would if you a sweet such as a cookie by itself.

  • On that same note, composition of all meals and snacks should be a combination of foods of healthy carbs with fiber and foods with protein. For example, a snack of grapes with a cheese stick will be a better choice than a handful of just crackers. Combining a protein source with a carb helps slow down digestion preventing blood glucose spikes keeping the readings more level. This prevents the pancreas from working overtime pumping out insulin to deal with a high blood glucose.

  • Any kind of movement or exercise clearly made a big difference in keeping my blood glucose levels from getting too high. After eating, if possible, get up and move around, go for a walk, do what you can to be active. This creates a demand of your body to use up more circulating glucose in your bloodstream lowering blood glucose levels.

  • I’ve always eaten my meals at regular times and never skip a meal. I do believe consistency of eating about every 3-5 hours throughout the day helps so much in regulating blood glucose throughout the day. Wearing the CGM clearly showed this.

  • Wearing the CGM made me much more aware of my food choices. I already eat well-balanced meals but wearing the device puts everything into perspective showing that the kind, amount and timing of food along with the kind and amount of exercise throughout the day clearly influence blood glucose levels. However, other factors can also affect blood glucose levels such as stress, medications, and illnesses.

  • This experience gave me a much better understanding and respect for anyone with diabetes, whether type 1 or type 2. They live with this disease every single day of their lives making decisions on how to better manage their condition.

  • I do believe if more individuals with either type 1 or type 2 diabetes could wear a CGM, even for just a little while, it could help them become more aware and motivated by making the connection the importance of choosing healthy foods at appropriate portion sizes, consistent exercise, adequate sleep and reducing stress can greatly manage their blood glucose levels reducing the risk of serious complications.

Continuous glucose monitors are primarily meant for people with type 1 diabetes but physicians can and do prescribe them for those with type 2 diabetes. Depending on the type of medical insurance a person has will depend on whether a CGM is covered or at least partially covered. Anyone with diabetes can always discuss with their physician the advantages of wearing a CGM to see if it would be appropriate for them.

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Cheryl Mussatto, MS, RD, LD

Cheryl Mussatto MS, RD, LD is a registered dietitian with a master’s degree in Dietetics and Nutrition from the University of Kansas and a bachelor’s degree in Dietetics and Institutional Management from Kansas State University. She is a clinical dietitian for Cotton O’Neil Clinics in Topeka and Osage City; an adjunct professor for Allen Community College, Burlingame, KS where she teaches Basic Nutrition; and is a freelance writer and blog contributor for Dr. David Samadi, Urologic Oncologist Expert and World Renowned Robotic Surgeon in New York City. Cheryl is also the author of The Nourished Brain, The Latest Science on Food’s Power for Protecting the Brain from Alzheimers and Dementia and The Prediabetes Action Plan and Cookbook, both available on Amazon in Kindle and paperback editions.