I am of course exaggerating with the title of this blog post. I have type-1 diabetes, therefore I am insulin dependent.

However, since being diagnosed seven weeks ago, I have become much less dependent on insulin than at first. In my opinion, this is down to two things. Firstly, when newly diagnosed, diabetics often experience the “honeymoon effect”. I don’t think this is fully understood, but it seems that before treatment starts, the remaining insulin producing beta cells are working flat-out and are totally knackered. (A bit like the shortly-to-be diagnosed diabetic!) When treatment starts, these cells recover a bit and can produce more insulin which helps newly diagnosed diabetics to control their blood sugar fairly easily.

Secondly, exercise makes the body more sensitive to insulin. I asked Dr Liu (she is running the monopepT1De clinical trial I’m taking part in) about this. The answer is clearly very complicated, Dr Liu simplified it for my benefit: when the body exercises, the body’s cells need to use more glucose for fuel. Rather than wait for the pancreas to produce more insulin, a process occurs locally which makes the cells more receptive to insulin.

September snow fall at 1800m. Beautiful running but I had cold feet!

September snow fall in Chamonix at 1800m. Beautiful running but I had cold feet!

Diabetics have to be aware of this because they don’t need to take as much insulin during and after exercising. Yesterday for instance, I went for a two-hour run followed by a six-hour walk both into the mountains. During the walk I ate about 120g of carbohydrate without taking any insulin – if I hadn’t been exercising this would have sent my blood sugar through the roof. However, if I didn’t eat it I would have experienced a severe hypo. This is why it’s really important that I do regular blood tests while I’m exercising – particularly as I get used to how different exercise affects me. This is fine for walking or climbing, but a little annoying while running.

My theory though is that during periods like now, when I’m exercising like a maniac, because my body is so much more sensitive to insulin, this allows the small amount of insulin I can still produce make a difference if my blood sugar gets high. I think this is probably why my blood sugar has been so well controlled. A diabetic marathon runner who did a quantified self presentation in the US said the same thing – his HbA1c levels (a measure of blood glucose control) were a full percentage point lower whilst training for a marathon.

I can manipulate the data I’m collecting to show the ratio of insulin to carb intake. The chart below shows this since my diagnosis. Now I need less than 0.25 units of insulin for each 10g of carbs. This creates a novel problem for me – my insulin pen doesn’t dispense small enough units! For instance, my plate of pasta this evening had 60g of carbs in. Do I take one or two units of insulin? One probably won’t be enough, but two would be too much. I solved this by taking two, and eating a peach and a square of chocolate after dinner. In the end I had to eat two more squares of chocolate (nightmare!) to avoid a hypo, taking my total carb consumption for dinner to 95 (and about 800 calories).

The blue line shows how many units of short acting (SA) insulin I am taking per 10g of carbohydrate I eat (three-day moving average). The pinky orange bars show are different heights depending on how much exercise I've done in those three days.

The blue line shows how many units of short acting (SA) insulin I am taking per 10g of carbohydrate I eat (three-day moving average). The pinky orange bars are different heights depending on how much exercise I’ve done in those three days.

From my very small, and statistically insignificant data set, I have drawn a strong conclusion. Exercise helps manage diabetes! I’m sure this goes for those with type-2 diabetes too.

For me this is great. My worries about diabetes stopping me from exercising have been addressed: running an ultra marathon might be difficult, but I am more motivated than ever to understand my blood sugar fluctuations so that I can do the stuff I love and manage my diabetes at the same time.


    1. Thanks for the comment. I’ve had a read of your blog and it’s really interesting. I was particularly interested to see your blood sugar results after cycling vs running. I find that my blood sugar goes up quite a bit after a twenty five minute hard run (I think because my liver releases glucose into my blood) and often goes up a little bit (but less) after a twenty minute cycle commute – which is obviously much less strenuous. On what kind of exercise is best for a type two diabetic – I’m not a doctor so obviously don’t really know – but I suspect that longer distance endurance runs make one more sensitive to insulin for the day or two afterwards. That was certainly true of when I actually ran the ultra – I had over 1000g of carbs that weekend – about 500 during then run but another 500 over the next day and a half, and I didn’t need any short acting insulin. That is remarkable. So I suspect that exercise has two effects – the first is the glucose change (driven up if the liver releases enough glucose into the system, and driven down if the exercise is long enough to deplete the liver’s glucose stores) and the second is the body’s sensitivity to insulin following exercise.


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