I've been tinkering around measuring my blood glucose levels at various times over the last couple of days. The primary reason for doing this is that there are reckoned to be a large number of undiagnosed type 2 diabetics in the UK and I thought it would be a reasonable thing to do to make sure that my blood glucose levels were generally in the normal range. Undiagnosed diabetes can do untold damage prior to it being diagnosed and I reckoned why not do a few tests out of interest.
Anyway, the results have been fine and I was also very interested to see whether my revised dietary regime was resulting in the desired level of blood glucose stability. I have been very happy with the results, my blood glucose levels, even when measured 60 minutes after a meal, have remained within the normal range, generally between 5-0 and 5.5mmol/L. The foods I'm consistently eating now are resulting in essentially no major fluctuations in my blood glucose readings, which was the primary reason for the modifications I've made.
Tonight I thought I would examine the effect of a 90+ minute endurance ride on the VELOtron on my blood glucose level. I rode the Port de Pailheres ErgVideo at a L2 intensity and measured my blood glucose before and after the session. During the ride itself I drank only water, I ate nothing and I didn't take on any specific carbohydrate foodstuffs before the session.
Prior to commencing the ride by blood glucose measurement was 5.7mmol/L and during the ride itself I performed 1124kJ. As you can see the calorie burn was not insignificant without taking on nutrition of any sort, I averaged about 200W for the duration of the session. There were some higer intensity efforts towards the end of the ride and at the end of the sesion I felt fine and my blood glucose level was 4.2mmol/L. Though lower this reading was still within the normal range which I was encouraged by, it looks as if I wasn't on the verge of a blood sugar "crash". This, to me at any rate, suggests that a substantial proportion of the energy requirements from the session were probably met from fat rather than carbohydrate stores, but I'm open to any interpretations folks may choose to offer! I think if I'd been using a lot of glycogen during this ride, given that I drank just water, the end level would have been far lower.
It's just interesting to try to build up a picture of what's going on inside when we do these exercise sessions and of course to be able to confirm these consistently normal readings is reassuring.