Continuous Glucose Monitoring while Running

I find a CGM to be of limited use during exercise as my levels change too fast for the 15 minute delay. By the time the CGM notices my levels have started to fall, I may already be hypo.
However, it is great to review what happens and change my approach next time.
Regarding which CGM to use depends upon your budget, your body (some people get better accuracy from one CGM and others get better accuracy from a different one) and your techiness (you can adopt the native readers or use unofficial apps to get more out of the CGM).
Libre is the most common due to its low cost. Assuming you have diabetes, you can get a free trial for 2 weeks from their website.

NCC1701 said:

Hi all. Any amateur runners out there that have tried Continuous Glucose Monitors and have T2 with meds Metformin and Gliclazide?
Can you share your experiences of these and perhaps recommend one?

I am training for 5km which I've done before but want to be the fastest I can be. Last race I was beaten by a 70 year old non diabetic! So something wrong on the energy transfer. I run this distance in 26:10 but aiming for 25mins...

Also training for half marathon. Has anyone used a CG monitor while training for such and which one please.

Many thanks all.

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Hi, I'm T1 but I have plenty experience running so here's some thoughts:

I was actually diagnosed quite late in life and already had a long background running. Initially I didn't have a CGM but found that I could run okay (ish) if I did short loops (around 5k ish) and would check by bloods by finger pricks each loop. During this time, I was cautious of doing longer runs, runs in really bad weather, or high intensity training sessions due to the uncertainty of how my bloods would react.

I went on to use the Libre. Instantly I was much more confident and happy to go on longer runs. The libre reader can be carried with you and buzzed against your sensor every couple of kms. I did notice that the sensor itself often failed if it was too cold (anything below around 5 degrees) so I would recommend long sleeved t-shirts and waterproof jacket if its raining.

I now use a dexcom. The thing is fantastic. No issue with cold or wet weather (its attached to my stomach, which probably keeps it warmer). It transmits data by bluetooth so if you carry a phone, you can get readings at whatever interval suits you. I also run with a garmin watch and use a third party app (XDrip +) to capture my BG and transmit the data to my watch so that I can see it at a glance when running.

One thing that I would stress is that whatever choice you make the key is that you should check BGs before during and after exercise and take fast acting carbs with you on the run. I use a trail running backpack that I pack with gels and glucose tabs. Gels normally contain around 20-25g of carbs and glucose tablets are normally around 3g/tab.

The FSL really has a delay of only 2.4 minutes on average so it does pick up fast changes while you exercise, I see this every day.

Unfortunately it falls off really easy and officially you are not allowed to wear a band aid or have the sensor on any other place than your arm. It also can’t handle cold or moisture and the algoritme really doesn’t like exercise at all, measurements are more than 50% off and my A1c came in 36% higher than predicted by FSL. In my case it often doesn’t pick up postprandial rises at all, so there is a lot I can’t learn from it. I really wish I had a Dexcom instead.

NCC1701 said:

I understand running with HR about 80% of max for my age can result in increase in BG so need to think about how to control that if I want to run faster for that PB! Thanks again

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I'd be very carefull, especially if you use BG lowering medication.
What helps is running later in the day or evening or at less than 80% of max.