This is where it all started - running in Chamonix in September made me want to do an ultra marathon in Chamonix. I found out yesterday that I have a place in the CCC - a 100km race from Courmayeur in Italy to Chamonix. It includes 7500m of vertical height difference.

This is where it all started – running in Chamonix in September made me want to do an ultra marathon in Chamonix. I found out yesterday that I have a place in the CCC – a 100km race from Courmayeur in Italy to Chamonix. It includes 7500m of vertical height difference.

Waking glucose – it was perfect for a few weeks round the start of December

I’m still in the honeymoon phase. That means my body produces a small amount of its own insulin and is therefore capable of controlling my blood sugar to some extent. In theory, if I was sensitive enough to this insulin, could my body control its sugar levels like a healthy person? Who knows!

For a few weeks before Christmas, I was consistently waking up with blood glucose readings of between 5 and 6 mmol/litre. That is basically PERFECT. It’s what a healthy person would wake up with. I started noticing that, and I also noticed that it was often 5.7 regardless of what level it was when I went to bed.

Over the past month it’s been between 6 and 7 when I wake up. That’s still good, but not PERFECT. I’ve noticed the change in trend and want to know why.

(Click on charts to enlarge.)

Wake up glucose

The blue line in the chart above shows my average waking up glucose. You can see a golden period before Christmas, where average waking up glucose was about five despite average glucose when I went to bed (red line) being higher. For the rest of the time, glucose on waking is pretty well correlated to glucose when I went to sleep. This suggests that my long acting insulin (Lantus – I take it before bed and it acts like “background” insulin, staying in my system for 24 hours or more) dose is about right.

What explains the really good waking glucose levels, and what explains them not being quite as good now? Please forgive the very busy chart below – it shows average waking and bed time glucose, how many minutes of running I did a day on average and average grams of carbs I eat before bed.

Factors affecting wakeup glucose

It’s not lantus

My Lantus dose has been steadily dropping as I seem to become more sensitive to insulin over time. (You can see I took it down to just four units while I was skiing, but it’s back up to 5 now.) There’s no obvious correlation between Lantus dose and waking blood sugar.

It’s not what food I eat at bedtime

If my blood sugar is a bit low when I go to bed, I normally eat something so that I don’t get a hypo. Am I eating more before bed now than I was? You can see from the chart that the opposite is actually true – I was eating slightly more before bed at the same time as my waking blood sugar was best controlled.

Could it be the running?

The other line on the chart is the number of minutes I’ve run a day, on average. In the lead up to my ultra, I was doing a lot of running (between 50 and 70 miles a week, or over 40 minutes a day on average). I wonder if doing all this running makes my body sensitive enough to insulin to enable my own insulin production to control my blood glucose to the optimal level? I’m going to ask my doctor.

The chart below shows my waking blood glucose, with periods where I’ve done over 35 minutes a day of running on average. You can see that there’s a rough correlation between waking with blood sugar of between 5 and 6 and me doing lots of running.

Running vs waking BG

I’m ramping up my running training again ahead of the London Marathon. I managed ten miles yesterday, 14 today and hopefully will do eight tomorrow. I’ll continue to monitor my waking glucose (of course!) and will be interested to see whether it starts coming in between 5 and 6 again.

I feel great to be running a lot again, and if it helps control my blood sugar better then that’s a nice bonus!


  1. Hi. Yes I think it makes a huge difference. I use running as one of my main forms of control. When I bust my ACL in 2007and had to stop for a while my HbA1c went from 6.5 to double figures and eye surgery to remove clots.
    Back now at 6.2 for last couple years, with ultra running as the reason. On my böog I discuss an experiment monitoring the effect of running v cycling. For me cycling pushes me too low. But that’s just me. Nice blog. Keep at it.


    1. Love the blog. My daughter is T1, she is 10 years old. Shortly after being diagnosed at age 9 we realised that exercise was a great way to control insulin intake and BG levels. She can walk up to 20miles during a walk. Her BG levels are so stable and this continues through to the next day. She swims 3 times a week and does other activities, each of them have slightly different reactions to her levels. Love reading things like this. Check her out on facebook: walkingwithdiabetes we just completed a week skiing where her BG were nearly perfect, her insulin intake greatly reduced. Now back home and less exercise and her insulin intake is back up and BG levels not so stable. We stopped posting on the affects on BG as we found some didn’t like us reporting on lows, but for us it was part of the learning experience, new to the insulin pump, so had to find the correct level. What are you doing in regards to lows when out running?


      1. Thanks for the comment and brilliant about all her exercise! When I’m running I normally know exactly how many carbs I have to take to keep blood sugar high enough: 10g each ten minutes. The only tricky bit is knowing when to start eating because my BG will go up or stay the same for the first 20 to 60 minutes depending on what kind of running i’m doing or just how my body reacts that day. I can guess what it’s going to do but I always test myself after 30 minutes in case it starts to drop. I haven’t actually had many instances of low BG whilst running because it’s relatively predictable and I’ve spent a lot of time understanding it (plus I very rarely exercise within 4 hours of taking short acting insulin – a constraint I wouldn’t have if I had a pump!). I’m surprised you’ve had comments about posting on low BG. I agree that it should help inform others. One of the reasons I wrote this blog is because I couldn’t find much information on exercise and type one, so hopefully discussing the highs and lows of blood sugar management is helpful to others!


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