Continuous Blood Glucose Monitoring for Endurance Athletes

5-minute increments, it looks like.

The sensor measures the level of glucose in the tissue every 10 seconds and sends the information via a wire to a cell phone-sized device called a "monitor" that you attach to a belt or the waistline of your pants. The system automatically records an average glucose value every five minutes for up to 72 hours.

I'm sure they'll speed things up in the next few years... I'm still not sure about sweat interference - since they measure a sample of interstitial fluid.  There's also the standard business practice that "It doesn't have to work - it just has to look good on TV."

I have had days where I was sure my nutrition was fine, but was really sucking at my workout.  A pack of gu later and I'm suddenly doing great...  Makes me wonder how often I thought I was just a wus, but really just had low glucose.  I've considered doing the pin test at various places/feelings during workouts for a while just out of curiosity.  On the other hand - I never even log my workouts unless garmin does it for me, so...yeah.  I'll probably will never do it.

I guess I wasn't clear on my point -- by the time it shows up in the blood, your stores are depleted to the point where you're not going to catch up without seriously affecting your performance.

But you might be able to catch a downward pattern (e.g. 150 to 120 to 90 in a short period of time) before it's "too late", no?

Like folks with Diabetes do...

steroids are VERY popular with recreational athletes and just general gym rats.  i've seen it firsthand in the bbing world and it's common in the military, but i wouldn't be surprised that other sports have significant levels of use.

While I agree that steroids are pretty common in rec. athletes, I think her point is that people who "just wanted to know" wouldn't be all that inclined to stick themselves to find out. After all, it's not like knowing your glucose will help you with the curls for the girls.

maybe it could turn into a new pickup line...like...."look how sweet i am!"

maybe not.

"sugar?"

"No thanks, I'm sweet enough already."

I found this thread because I periodically look for the word 'diabetes' on the forums here...

I have Type 1 diabetes, and use an insulin pump and a cgm (continuous glucose monitor).  Some points:  a) the cgm is actually measuring the glucose in your interstitial fluid, so there's a delayed effect.  For instance, recently when running I felt low.  My cgm said I was 98 (perfectly reasonable) and heading downward quickly.  Well, actually my blood sugar was already in the toilet (probably 50s), but the cgm hadn't quite gotten there yet.. :-).  but b) the cgm is very useful in general, and especially for getting trend data.

It might be interesting data to see what happens with a non-diabetic's blood sugar during endurance events, but I suspect you'd find not much happens at all.  If your blood sugar varies this much <>, my range is this: <                                      >, and sometimes it bounces around in there often and wildly. 

A cgm costs about $1000 to get started and about $360/month for the sensors (I use a Dexcom, and the sensors are technically good for a week, but you can get more time than that out of them).  Since many people with diabetes have insurance that won't approve a cgm, I can guarantee that it won't pay for this technology for a non-diabetic.

A cheaper option, which you may've discussed before, is to get a glucose meter and strips.  Then test when you feel bad, or at set points in an effort.  Certainly some people experience hypoglycemia when in the middle of a swim/bike/run (the head coach of my training group has had real problems with this), but it's not as common as supposed.  There are other reasons for the dreaded bonk...

That's interesting info.  At least we know it works during activity.

I didn't know there was a question of it "working" or not... just the delay?

My nephew wears what Prudence does, the Dexcom. I think if people (recreational athletes to be specific) knew exactly what was involved with the site changes and issues that come with the device, plus the cost without insurance assistance--- it wouldn't be remotely appealing or even brought up in discussions... would you agree Prudence?

Given the current info, cost, and capabilities that it's not a worthwhile consideration.  I did know they were sampling interstitial fluid, and wondered if copious amounts of sweating would interfere with that sample.  I guess I'm not familiar with the Dexcom - I was only thinking of non-invasive gadgets being useful for recreational athletes.  (no needles - no site changes).  The little I know of them, they are in their infancy.  Give it a few years, and maybe they'll get better and come down in price.  I'm imagining a device that's as easy to use as our HRMs.

Even with a lot of sweating, the cgm works fine.  You could even stick the receiver in an Aquapak if you want to take it swimming (I've done that with my not-waterproof insulin pump for really long -- Ironman -- swims, but usually don't bother being hooked up to the pump when swimming).  Some people do have problems with the adhesive coming loose with lots of sweating, but I don't, and there are all kinds of bandage tapes and adhesive liquids to help with that.

Really, though, if you're interested in the data and don't want to spend copious amounts of money (and I believe the cgm requires a prescription, too), you could easily purchase a glucose meter.  Now, this involves stopping and pricking your finger and all (and you can't do it in the middle of an OWS :-), but it might give you good information if you suspect your blood sugar is tanking sometimes. This way you'd also not have a needle stuck into you for a week, which may not appeal to many.  If you do find that you're going low, a visit to a dietician (a sports dietician who works with diabetic athletes would be best, but there aren't many of those) and some trial and error should fix the problem.

In the diabetes world, the cgm is a luxury that provides useful information and I'm grateful for it (especially when training long and hard).  That said, it's an imperfect and costly tool, yes even with insurance -- unless your insurance will pay 100%, but I don't think any will do that now.  I think it's great that non-diabetic athletes are thinking of using this, I do, but I'm kind of torn.  I wish everyone with T1D could get one first...

Sorry to dampen the lighthearted nature of this thread.