The woman rises slinkily from the hot tub-long, wet hair glistening in the sunlight, a picturesque sunrise before her-and the glucose monitor continues to be perfectly centered on the back of her right arm.
Here’s a scene from an ad for one of those trendy continuous glucose monitors (also known as CGMs) that popped up on my social feed recently.
It’s not like my life with CGM—and I need to know what this life is like. I have type 1 diabetes for a quarter of a century, since I was 12. And I have used various CGM products for more than a decade, from relatively large sensors “stapled” to the stomach to pill-sized sensors implanted. under the skin of the upper arm.
And let me tell you, it’s not a glamorous life.
In the latest trend in health wearables, manufacturers of technology developed to help diabetics – by warning of potentially deadly high and low glucose episodes – are now marketing their products to non-diabetics. The distance: Sensors inserted between the layers of the skin via spring-loaded needles will provide metabolic insights that can lead to changes in diet and exercise.
Don’t get me wrong – I am very grateful for CGM technology. It’s come a long way over the years, from anxiety-inducing distractions that constantly throw off false alarms, to life-saving technology that almost always reliably alerts me to high and low glucose levels.
But I don’t look like a model. After years of getting a CGM on the back of my upper arm (also injecting insulin and putting an insulin pump and infusion site pod in there), mine is worn and bruised—to the point where I sometimes question whether I’m safe going forward.
And a long soak in a hot tub? It’s a no-go (or “proceed with extreme caution”) for me, as someone whose CGM is medically necessary. Diabetics are warned to be very careful in hot tubs, as the heat can cause hypoglycemic awareness that prevents warning signs of low blood sugar, such as shaking and sweating.
You would hope my CGM would alert me to low glucose episodes but—as I know first hand from testing in long, hot baths—they tend to stop reading if submerged for a while. (I spend more time ignoring the “lost signal” alarm than relaxing.)
If you’re relying on readings from your CGM, be wary of longer periods of time in the water – that’s one lesson I’ve learned from more than a decade of wearing CGMs. Here are some more.
Getty Images
1. CGM does not measure blood sugar.
Yes, you read that right. And yes, a lot of people say it wrong – even some of the so-called “pros”. CGMs do not measure blood glucose levels. They measure glucose in the interstitial fluid, between the layers of tissue. Glucose tends to flow from the blood vessels into the surrounding tissues. Interstitial fluid glucose levels are similar to blood glucose levels, but are delayed by 15 minutes or more.
For non-diabetics, lag makes no difference. For diabetic patients, it may mean delaying the signs of low glucose levels and, therefore, treatment.
Getty Images
2. Food and exercise are not the only factors that affect glucose levels.
CGM is marketed to non-diabetics as a tool that allows them to observe the effect of food on glucose levels. But many other factors can affect these levels, from certain illnesses and medications to stress, lack of sleep, and menstrual cycles. I once attended a meeting with my son’s school with a fairly normal blood glucose level, and then got angry—and read in the 400s. (The meeting didn’t go well, to say the least.)
Getty Images
3. The sensor is easy to wear for a week or two-and much harder to wear more than that.
Some companies are marketing CGMs to non-diabetics as a temporary inconvenience. Wear the sensor for two weeks and get data on the effect of food on the correct level of glucose for a year, he said.
But this scenario does not apply to diabetic patients, especially those who do not know hypoglycemia.
The longer one has diabetes, the greater the chance of developing the condition, a form of neuropathy that makes CGM a daily necessity. Don’t get me wrong – I am very thankful for my CGM. But my arms looked broken—as did my stomach, when I wore them there.
(Regular CGM users are encouraged to rotate “sites” when possible—arms, legs, abdomen, upper buttocks—to conserve “real estate”. The latter cannot be reached without assistance. And, not all sites work for all diabetic patients.)
Getty Images
4. CGMs can alleviate the “cognitive load” of diabetes—but they have the opposite effect for non-diabetics.
It is estimated that people with type 1 diabetes make about 180 health-related decisions every day to maintain their glucose and ketone levels. The medical term for this: “cognitive load.”
When I was younger, my dad would sometimes sit down on Saturday mornings and monitor my glucose levels using a traditional blood-based monitor, so I could get some extra sleep. Using a CGM is like having that level of assistance—but better, and all the time. It allows me to move more focus elsewhere, knowing that someone is keeping an eye on things. It helps shoulder the cognitive load.
For non-diabetics, however, CGMs can have the opposite effect. Unless you have hypoglycemia, pre-diabetes, or other health conditions that put you at risk of high or low blood glucose levels, you may find that the sensors cause a situation of information overload. As someone who has no problem maintaining healthy oxygen saturation or blood pressure levels, I can’t imagine being presented with a constant stream of data (and trying to process and interpret relatively small variations). Honestly, such a “tool” would probably send anxiety through the roof—and I have to wonder if CGMs do the same for at least some non-diabetics.
5. Not everyone has equal access to this life-saving technology—and that’s a problem.
Insulin, insulin pumps, and now CGM—add to the list of expensive treatments that diabetes requires but cannot afford. For diabetes-especially type 1s-the cognitive burden is a thing, but also a financial burden.
But there is a lack of access to CGM among racial and ethnic “minorities” that cannot be explained by socioeconomic status alone. According to a study published this year in a medical journal diabetes treatment, using diabetes technology like insulin pumps and CGMs is more than 20% less expensive in black patients compared to white patients. And according to a 2021 study in the same journal, less than a third of black youth have access to insulin pumps and CGM, while nearly three-quarters of white patients (40% of Hispanic patients have access).
Among the reasons: provider bias, systemic racism, and (understandably) distrust of the medical system, the authors of the next study speculate.
For non-diabetics using CGMs, my message is this: Enjoy the new gadget-even if the insertion can be quite painful, which takes away some of the fun. Use the data to improve your health, if you can. And if you find that’s not all you want, consider donating unused, unexpired CGM sensors to charities like Insulin For Life, which distributes supplies to diabetics in developing countries.
A device that annoys and disappoints you can save the life of a diabetic patient.