Borderline A1C levels (pre-diabetes)

Anyone here dealing with having elevated A1C levels in the range? I have had levels of 5.6-6.0% over the past 5 years, which as part of my annual physical flags me as someone needing to investigate more. Their typical advice – lose weight, exercise more, eat better, doesn’t really apply to most of us, given our levels of fitness. I AM investigating the eat better lever. I generally eat very healthily, but want to look into dialing in macro balance, timing, portions, better. And while I don’t eat fast food, sugary snacks/drinks off the bike, I of course eat lots of sugar on the bike and wonder if something I am doing is inadvertently impacting my body’s ability to regulate blood sugar.

My physical this year had some other borderline results that may/may not be related (slightly elevated potassium, low specific gravity), so I am digging in a little more.

I have read some articles/studies about endurance athletes and predisposition for diabetes, but not sure I am any wiser. Maybe a podcast topic?

I’m betting that we’re going to see an increase in a cohort of people who participate in endurance sports succumbing to type 2 diabetes and pre diabetes.

The doctor’s advice of losing weight and eating better will still apply and that may be where an endurance athlete is lulled into a sense of security. By the metrics of the general population, it would appear that an endurance athlete is not that overweight/obese and gets plenty of exercise. The constants that you can’t control, however, is time (old age) and genetics. Overweight and obesity are risk factors, but uncontrolled blood sugars is multifactorial and specific to the individual. A primary care physician may only be versed in dealing with the general risk factors but specific and specialized care may take a more well versed professional.

The biggest thing you can do is to measure and probably decrease your carb consumption. How deep down the rabbit hole of measuring do you want to go? The first part is to measure yourself. If diabetes runs in the family and/or you’ve done some genetic risk factor testing, that’d be a start. One of the best baseline tests of your ability to handle carbs is the Glucose Tolerance Test (GTT). If you go more advanced, and with the help of a physician in the know, you can couple that GTT test with an insulin test. From this, you’ll get a good idea of how you respond to a glucose challenge. The goal with this combo test is to see if you’re in this weird area where you may have glucose control but am seeing some insulin resistance.

The next step is that you can start measuring your post meal blood glucose. Your fasting blood glucose probably won’t tell you much but knowing the trend of your glucose levels after a meal can be pretty eye opening. Maybe some favorite meals in which you thought was healthy is devastating from the perspective of insulin resistance. Finger stick based testing is very cheap nowadays but we’re interested in your post meal trends so some sort of continuous glucose monitoring is most desirable. That’s more expensive and in some countries a prescription is required. From there you can address diet and behavioral changes while getting some immediate feedback through the glucose testing.

Other risk factors with regard to diet include saturated fat consumption. Higher saturated fat consumption increases the chances of insulin resistance. Timing of carb consumption is important. Are you loading carbs throughout the day? Only carb up for your activity and also an appropriate amount. What are your goals for cycling? Health? or Podium finishes? Maybe you don’t need much carbs at all if being a peak performer isn’t your objective.

Do you fast? Evidence shows that fasting every once can have beneficial effects that last. Another behavioral change that should be considered.

I would say the biggest controllable risk factor for endurance athletes and the predisposition for diabetes is behavioral. It’s not knowing how they are being impacted by their diet and not adapting to their aging body.


Wow. I can’t thank you enough for your detailed response. You have provided essentially a great roadmap for me to think about. I already made an appointment

I’ve tracked food before and talked to a general nutritionist who was checking for my macros and quality/quantity of food, but didn’t dive into timing or testing. Seems like a logical next step. This year I DID increase my carb intake to fuel indoor rides in the early AM, or the night before big weekend rides.

I am 45, 5’ 11" 70kg and have generally have felt fit. Pre-diabetes is part of a larger health concern that is building as I get older and ailments accumulate (Reynaud’s, Orthostatic Hypotension, Low BP/Blood Volume, Periodic viral brain infection, recent enlarged heart diagnosis) that all impact my quality of life, let alone quality of training. I have found that exercise, and cycling specifically, has been a critical component to balancing my health.

Thank you again. Very much appreciated.

Get a fasting insulin level test. Blood sugar levels don’t give any real clue as to your level of insulin resistance. I think there was a Flo podcast recently talking about this subject with respect to endurance athletes.

1 Like is the mentioned podcast.

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No problem!

You’re still young and your BMI is so low! Considering diabetes only brings on complications of the circulatory system it’s a good thing you’re trying to head it off before it becomes a bigger problem. Have you considered going low carb? If you’re just cycling for fitness, it seems like the pros would outweigh the cons.

I have tried low carb in the past. When I was 40 and 82kg I started with that for about 2 years. Then I started going to the gym, then started cycling. It was when cycling became the major portion of my fitness routine (2016) that carbs starting coming back into my diet. 2014 was my first A1C test (Dr. started including it in blood panel) and it was 5.7%. Dr. wasn’t too concerned, but said to monitor. At that time I was going to the gym regularly (no cycling), at a healthy weight, and probably was low-ish carbs.

Most doctors are great at healthcare, however, IMO healthcare has a different meaning. It should really be called sickcare. Their training leans towards the focus on identifying, and treating diseases without nearly as much of a focus on prevention.

Not to scare you or anything but if you’re in the 5.6-6.0% range I would really work on doing what you can. That statistic puts you at a higher risk category for type 2 diabetes. I know a lot of the trainerroad podcasts advocate carbs for high intensity, but if you’re not in it to win it, focus on your health.

An ounce of prevention is worth a pound of cure and I think you have a great opportunity here to get a lot done. Type 1 diabetics have an extremely hard time keeping their A1Cs below 6 and I’ve known a family with type 1 teenager be able to get his down to a 5.0 which is a huge accomplishment. If you’re ever looking for ideas on diet, a good type 1 diabetics group will probably have the best info you can find as they have to know.

What you described is exactly what I have, A1C of 5.7 to 6.2 for the last 10 years. Lost a bunch of weight and exercise, didn’t help. It went down to 5.4 once after donating blood.
However, more concerning, what got my attention is your enlarged heart diagnosis. I had that diagnosis back in 1992, which led to heart surgery for birth defect I had for 30 some years, SVASD. Along with your Reynaud’s, Orthostatic Hypotension, Low BP/Blood Volume you might want to have that investigated further.

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This gives me a little bit of pause as it’s not “of course”. I ride 8-12 hours per week and hardly ever resort to sugar. I usually take a banana with me, a rice cake bar sometimes, and only some extra sugar when I know it’s going to be a long/intense 4+ hour ride. I’ve only resorted to gels in fondos/events.

Anyway, it’s something to think about. Most rides don’t need to be “fueled” other than with healthy food.

There are conditions where a HgA1c test might not be accurate. I have a genetic anemia (thalassemia minor) that presents no problems for daily life and requires zero treatment but if I take a HgA1c test it will show as borderline or high. There are a bunch of things that can cause this borderline result so I’d research that and rule them all out before you decide you are borderline.

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Thanks very much!

To give an update, I ended up monitoring my blood sugar for two months and it never went out of range, which satisfied my doctors. I also deep a deep investigation of my heart - they debunked the enlarged heart, did 2 MRIs with contrast, and other tests and my ticker is fine, which was a relief (understatement!).

You make a great point, and I have started experimenting with adding much more “real” food on the bike. I have found though that I do require a fair bit more of energy on the bike that I have been consuming in the past to avoid fatigue. So trying to get that in line. Thanks!

If you are interested you can google “James Morton” and “carbohydrate periodization”. He is the exercise physiologist that works with Ineos and a lot of other pro teams.

The gist is that you can train your body over time towards better fat utilization. If you give your body sugar for every workout you train it towards glycolysis.

Actually, I just just reading this Alan Couzens article on the same subject: