Bicycling: Effects on Fasting Blood Glucose

Ok, I’ve been bicycling for 7 days now, attempting to lower my fasting blood glucose (FBG).  Before I get into whether or not this is having the desired effect, let’s look at my history of using this particular exercise to reduce FBG.

In the Spring of 2011, a good 9 months before entering the online world of nutrition gurus, I bicycled every day for a couple weeks.  At this time my blood sugar was in the pre-diabetic range.  I was eating a standard American diet (SAD), probably not much sugar, some starches, some processed food, diet coke every day, still eating gluten.  Here were the effects at that time of bicycling and tracking calories:2011 Blood Sugar

Now, I don’t recall exactly what “tracking calories” meant – I didn’t have a blog back then so I can’t revisit those dates and see what I was doing.  Knowing me though, I was trying to stick to around a 1500 calorie diet.  As you can see from the graph above, bicycling + tracking calories was a good thing – my FBG was in the 90s within a few days and in the 80s within about a week and a half.  I was biking for about 30 minutes at a time on flat terrain, moderate intensity – just enough to sweat and breathe a little harder but not enough to be exhausted. I stopped because I got sick (I don’t remember what with) and the temperatures outside soared to over 110 degrees.  Got out of the habit and didn’t restart.  Maybe because my diet was consistently making me depressed.

Fast forward to September 2013 – my next experiment with biking.  Here’s a graph of my FBG then:

2013 blood sugar

This was a month before I began my Peat-inspired lifestyle.  Fasting blood sugar at the time was mostly in the pre-diabetic range (under 126) with occasional higher spikes.  I began a “lower-cal diet” and bicycling, and continued with that for almost 2 weeks. “Lower-cal” at that time meant shooting for 1500 net calories (after exercise).  I remember being kinda hungry – but I didn’t really spend a lot of time researching low-calorie high-nutrient high-satiety foods at that time.  About 50% of my calories were in the form of fat, 25% protein, 25% carbohydrate.  Other than that, nutrients weren’t really on the radar yet.

During that time my blood sugar stabilized around 100 (a good 15 points lower), with dips into the 90s as early as 6 days into the program.  If I had continued the trend may have continued.  I stopped because my focus at that time was weight loss, and I wasn’t losing.  My temperature and pulse were dropping, and new-found information from Ray Peat world made me think my metabolism might be suffering.  So I stopped.

Ok, so now let’s look at today.  I’ve been bicycling with NO dietary change, for 7 days now.  As in the previous exercise programs I’ve been biking for 30 minutes or so, medium intensity, flat terrain.  Let’s look at the data:

FBG May 2014

Blood sugar is….remarkably stable.  And unchanged in the last week. NO CHANGE.  It may have been unrealistic for me to aim for the 90s within two weeks, considering my baseline level is higher now, but I would hope to see at least SOME movement in the right direction.

So what’s missing?

Well, the previous two times I biked regularly I was also counting calories, shooting for around 1500 calories per day.  Over the past week I haven’t been monitoring what I eat at all.  My weight is down a pound or so and I haven’t been overeating, but I haven’t been counting anything.  I tend to eat around 2200 calories a day when not attempting to reduce, so it’s safe to say I’ve been consuming at least that much.

So it appears that for me, blood sugar management is going to involve not just regular exercise but also a reduced-calorie diet.  I don’t know if it has anything at all to do with eating low-fat….just low-energy (calorie).  I’ll have to research ways to stay full.  Hunger has always been the obstacle to me sticking to a reduced calorie diet.

I’ve started counting calories today.  Will continue on with bicycling.

Score one for conventional wisdom.

7 thoughts on “Bicycling: Effects on Fasting Blood Glucose

  1. Hmmm fasting sugars consistently above 140. Not good. Are you bumping up the RS and probiotics yet? How much thyroid are you on now?

  2. Do you get hypoglycemic with thyroid? Its going to be a difficult battle without thyroid support.

  3. I was taking a tiny bit before and my temps/pulses were good. I stopped taking it and they’re actually a little better (probably because of the starches, not because of stopping thyroid). Now my waking temp is usually over 98, and daytime over 99. Seems weird to add thyroid with that as my baseline. What do you think?

  4. That is weird. I would imagine you have enough PUFA stored to supress your thyroid. At 1.65 your TSH is not too high also. But it could be lower and your lipid profile might benefit from a bit. It would be interesting to see if your temps might actually fall with some thyroid. It could indicate more adrenaline/cortisol and explain the high sugars.

  5. I’d like to blame my high sugars on adrenaline/cortisol, but my post prandial readings are high too. I’m just diabetic. I could give thyroid another go. Wouldn’t hurt I guess.

  6. @Newtopaleo,

    May I ask what brand of thyroid you recommend? My TSH is about 2.9, I’ve got some issues with low energy levels (but I tend to attribute that to chronic insomnia) and I’m always a little colder than those around me. Just curious about possibly experimenting a little.

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