**Denver Trackers: Altitude Lies About Blood Sugar?**
By Franklin Everett ShawImagine stepping out of the Denver airport, the crisp mountain air filling your lungs. You’re ready for a hike, a conference, or maybe just a relaxing vacation. But if you’re one of the many people in Denver managing diabetes with a continuous glucose monitor (CGM), that initial breath of fresh air might be the start of a confusing experience. Your CGM readings might seem…off. Higher than expected, lower than they should be, or just plain inconsistent. What’s going on? The answer, surprisingly, might lie in the altitude.
Denver, the “Mile High City,” sits at 5,280 feet above sea level. This altitude, while invigorating for some, presents unique physiological challenges, especially for those using CGMs. The thinner air means less oxygen, and this can subtly, yet significantly, impact how your CGM functions and how your body processes glucose. It’s not a flaw in the technology, but rather an interaction between the device and the high-altitude environment.
CGMs don’t directly measure blood glucose. Instead, they measure glucose levels in the interstitial fluid, the fluid surrounding your cells. This measurement is then translated into an estimated blood glucose reading. At higher altitudes, the body responds to lower oxygen levels by increasing red blood cell production. This, in turn, can affect the composition and flow of interstitial fluid, potentially altering the accuracy of CGM readings.
One key factor is blood oxygen saturation. At altitude, your blood oxygen saturation naturally decreases. This hypoxia (low oxygen) triggers a cascade of physiological responses, including increased heart rate and altered blood flow. Some studies suggest that lower oxygen saturation can interfere with the electrochemical reactions within the CGM sensor, leading to inaccurate readings. While the exact mechanisms are still being researched, the correlation is becoming increasingly clear.
So, what can a Denver resident with a CGM do to navigate this high-altitude hurdle? Here’s a practical, step-by-step approach:
Acknowledge the Potential Discrepancy: Understand that your CGM might not be perfectly accurate at altitude, especially during the initial acclimatization period. Don’t panic if you see unexpected readings.
Fingerstick Confirmation is Key: Regularly confirm your CGM readings with a traditional fingerstick blood glucose meter, particularly when making critical decisions about insulin dosing or treating hypoglycemia. This is especially important in the first few days after arriving in Denver or when engaging in strenuous activity.
Calibrate More Frequently: If your CGM allows for calibration, consider calibrating it more frequently than usual, especially if you notice significant discrepancies between your CGM and fingerstick readings. Follow the manufacturer’s instructions carefully.
Hydrate, Hydrate, Hydrate: Dehydration exacerbates the effects of altitude. Drink plenty of water to maintain adequate blood volume and fluid balance, which can help stabilize CGM readings. Aim for at least eight glasses of water per day, and even more if you’re active.
Monitor for Symptoms of Altitude Sickness: Altitude sickness can further complicate blood sugar management. Symptoms like headache, nausea, and fatigue can mimic hypoglycemia or hyperglycemia. If you experience these symptoms, consult a healthcare professional.
Adjust Insulin Doses Carefully: Be cautious when adjusting insulin doses based solely on CGM readings at altitude. Err on the side of caution and consult with your endocrinologist or diabetes educator before making significant changes to your insulin regimen.
Consider CGM Placement: While not definitively proven, some individuals find that CGM placement can affect accuracy. Experiment with different insertion sites to see if one location provides more consistent readings than others. Avoid areas with poor circulation or excessive sweating.
Communicate with Your Healthcare Team: This is perhaps the most crucial step. Inform your endocrinologist or diabetes educator that you live in Denver and are using a CGM. They can provide personalized advice and adjust your treatment plan accordingly.
To gain further insight, I spoke with Dr. Emily Carter, an endocrinologist at the University of Colorado Hospital in Aurora, a suburb of Denver. “We see this issue frequently with our patients,” she explained. “The altitude definitely impacts CGM accuracy for some individuals. We emphasize the importance of fingerstick checks, especially during the initial acclimatization period. We also encourage patients to discuss their experiences with us so we can tailor their treatment plans.”
Dr. Carter also highlighted the importance of considering individual variability. “Not everyone experiences the same degree of CGM inaccuracy at altitude. Factors like age, overall health, and the specific type of CGM used can all play a role.” She recommends that patients keep a detailed log of their CGM readings, fingerstick results, and any symptoms they experience to help identify patterns and potential triggers.
One common pitfall is relying solely on CGM readings without confirming them with fingersticks. This can lead to incorrect insulin dosing and potentially dangerous blood sugar fluctuations. Another mistake is assuming that the CGM is always wrong. While altitude can affect accuracy, the CGM can still provide valuable insights into blood sugar trends and patterns.
Another challenge is differentiating between altitude-related CGM inaccuracies and other factors that can affect CGM performance, such as sensor placement, hydration levels, and medication interactions. A systematic approach, involving regular fingerstick checks and communication with your healthcare team, is essential for accurate blood sugar management.
For example, consider a Denver resident named Sarah, who recently started using a CGM. Initially, she was thrilled with the convenience of continuous monitoring. However, she soon noticed that her CGM readings were consistently higher than her fingerstick results, especially after her morning hikes in the foothills. After consulting with her endocrinologist, she learned about the potential impact of altitude on CGM accuracy. She started calibrating her CGM more frequently and carefully confirming her readings with fingersticks. She also adjusted her insulin doses slightly, under the guidance of her doctor. As a result, she was able to regain control of her blood sugar levels and continue enjoying her active lifestyle.
Living in Denver with diabetes and using a CGM requires a proactive and informed approach. By understanding the potential impact of altitude on CGM accuracy, regularly confirming your readings with fingersticks, and communicating with your healthcare team, you can effectively manage your blood sugar levels and enjoy all that the Mile High City has to offer. Don’t let the altitude be a barrier to your health and well-being. Embrace the challenge, adapt your strategies, and thrive in the mountains.