Endurance athletes and Hb A1c

Marbles

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Until recently, I was not aware of most of the below, and I doubt many providers are as it applies to a small subset of American society. But, probably a much larger subset of RS, so I figured I would share it here and perhaps save someone else some stress.

At my recent well check my A1c was in the American prediabetic range at 5.8%. I'm also over weight by BMI, but not over fat by Dexa scan (19.2% body fat). So, at an office visit I look like a higher risk individual than I am and lifestyle modification was recommended (weight loss, exercise, diet improvement).

Endurance athletes commonly have Hb A1c's that are high by the American standards, but have excellent metabolic flexibility (not prediabetic, no metabolic syndrome).

The question becomes, does one have glucose regulation issues as this influences lifestyle recommendations. In the end accurate assessment, not denial, is the goal. Health care providers see a lot of denial, and the arguments in this post would certainly come across as such. So, the following things can clarify the clinical picture for both patient and provider:
-A normal fasting glucose argues against this (mine was normal).
-A normal fasting insulin argues against this (mine is normal, I had to request it)
-If my provider remains concerned, I will ask for a glucose challenge test as that gives the most direct assessment of glucose management in the body.
-A LPIR (Lipoprotein Insulin Resistance score) comes up, I'm not sure if it is validated in endurance athletes, and being an indirect measure used to assess risk it is of questionable value in any population it was not validated in.

The other difficulty is proper fueling as an athlete, which is driven by lots of carbs. The key here is full blown diabetes should consume carbs at the level recommended for none diabetes during exercise. So on heavy days 900+ grams of carbs (over 3500 calories of carbs) fall within my recommend consumption range.

The ADA (American Diabetic Association) is the only organization that recommends the 5.6% threshold on Hb A1c as being prediabetic, the rest of the world uses 6.0%. Athletes engaging in more that 300 minutes of moderat to high intensity cardio a week probably shouldn't be concerned until they are 6.0%.

The 300 minute cut point is based on intuition, there is not much hard data available on athletes when it comes to this topic. Anyone getting less than 300 minutes a week is leaving easy long term health gains on the table anyway, so increasing would be to their benefit regardless of if the Hb A1c is a sign of a problem or not.
 
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