Running On Insulin

Running On Insulin

Running was alien to me back in April. I didn’t have a clue how my blood sugars would react to running. Would I go high due to the exercise? Would the exertion cause me to drop like a stone? In reality I didn’t have a clue what would happen. 

I had a look around online and it is awash with information, some of it really good, some of it pretty dangerous to be fair. So armed with very little knowledge I laced up my trainers and set off to have a run about. In fairness, this is probably the best approach. Any person with diabetes will tell you that none of this can come straight from a text-book. Our diabetes is as unique to us as our fingerprints, the only way you will learn what works for you is to try it.


In this blog I want to share what I have learnt about my diabetes and running on insulin in the past 8 months. Take from this what you wish, but please be aware this approach works for me, it might not be any use to you at all. I am not a qualified Dr, nor a sports scientist, this is just my experiences I’m sharing with you. Having run over 1200 KM since April, I’m starting to get the knack of it now.

One thing to note is the general rule that running will cause a drop in blood sugars, it is this that I needed to learn to manage.


Don’t Suspend Basal 

This was how I started off with running. I had a few runs where I was going low, first thought was to just leave my pump at home. Sure it helped with the lows, but the unexpected side effect was ketones. Even although my blood sugars were at a very nice 6 come the end of the run, my ketones were at 3.8 All it takes from this point is my blood sugar to go haywire and DKA will be beckoning.

running on insulin
Insulin, My LifeFuel, My Nemesis


Reduce Basal

After lots of trial and error I have found my sweet spot. If I am out for a long run I reduce my basal by 90% 1.5 hours before I start running and whilst running too. This may work for you, I would suggest starting with less of a decrease and using trial and error to find your own sweet spot.


Active Bolus – A No Go

Key for me is to ensure I have no active bolus insulin on board when I’m running. This means either running early in the morning before breakfast in my fasted state or at least 4 hours after my last bolus.


Why Not Just Start With Higher Blood Sugar

This was an approach I used early on, sadly it doesn’t work. When you look into where the body draws fuel from when running you will see why this approach just doesn’t work. You will still drop like a stone, and in most cases for me the hypo is worse if I have dropped from a height! Fueling properly is the key here.


Glucose Is For Fuel – Not Just Hypos

This was a big one for me. I was finding that I could start a run on a 9 or 10 and within half an hour be having a hypo. The key to stopping this was to fuel myself correctly. It seems odd to take 3 glucose tablets when your bloods are already at a 9, but trust me it works. I get a small spike from the initial glucose hit but then I level out and I’m good for 40 minutes of running. At the 40 minute mark I need another 3 glucose tablets then I’m good for another half an hour or so.

running on insulin
Example Of Fuelling A Run

Using a CGM I can see this approach enables me to stay pretty much flat whilst exercising. This has given me the confidence to start a run on a 5.5 nowdays. 

running on insulin
It’s Not Always Like This


Keep Hydration And Fuel Separate

Go on to any running website and they are awash with different hydration drinks. The vast majority of these will also contain carbs. I have found that if I use the carbs in these drinks as my fuel, instead of the glucose tabs, then I still struggle to hit my sweet spot on the blood sugar front. My rule now is to keep my hydration and my fuel as two separate things. In honesty I use water to hydrate, it’s natural, free and it works.


Rehydrate After Too

Exercise will take its toll on levels in the body. It is essential to replace the lost nutrients after exercise as well as before and during. Using a hydration tablet is a great idea, get the correct ones and they shouldn’t affect your blood glucose. There are so many on the market, a few can be found  ➡ Here

running on insulin
Image Courtesy Of J.Moran Sports Nutritionist


Carbs Are Not The Work Of The Devil

I’m not putting this here to start the whole low carb debate, in fact I used to go down this route. If you want to be a runner, and perform well carbs are your friend and not the enemy. I like to use the analogy ” You can run a car on vegetable oil (low carb), but if you want performance petrol (carbs) works better” If you try to run without fuel on board the inevitable will happen. 

running on insulin
Image Courtesy Of J.Moran Sports Nutritionist


Trial And Error Is Your Best Friend

This is never truer than when applied to diabetes and exercise. All aspects of my diabetes have been tuned using this method. Try something, see the results and make what changes you think. Then try it again and see if it worked.


The 10 Second Sprint – Who Knew

This is a great little trick and it works. If you see your blood sugars are dropping low, put in a 10 second sprint. By sprint I mean absolutely flat-out, as if you were being chased by a lion type of sprint. This will result in a spike in your blood sugar levels, pulling you back into the range you want to be in.


CGM Really Helps

If you have a CGM then it will fast become your best friend when running. I use the Dexcom G5 and by running through Nightscout I can have my blood sugars on my Garmin watch. Being able to see a trend arrow really does help prevent hypos. As soon as I see the trend arrow going downwards I start to think about taking some glucose on board.


No Run Is A Fail

When starting out you will find that very often you will end up high, low or just plain knackered. Don’t be disheartened, use the run as a lesson. Analyze it and see what happened and try to have a plan to prevent it happening next time out. 

I am now at a stage where if I do hypo mid run, I will stop, treat the hypo, wait and then carry on with my run. Diabetes is no barrier to determination. 


I hope this blog has given you a little insight in to the approach I take to running on insulin. I’m not saying any of this is the only way, or even the right way, but it works for me….. well most of the time anyway. All of the above is just to do with my diabetes and running, the fitness side of things, well that’s down to you! The best thing about running, all the gear you get to treat yourself to. 

running on insulin
Got To Love A Bit Of Branding


If this blog has helped you to understand what happens when we try to run on insulin then I’m well chuffed. I will be using all of the above techniques in the build up to my ➡ marathon challenge in 2018. If you could support me in my fund-raising that would be amazing and very much appreciated.

JustGiving - Sponsor me now!




For now

 Take Care, Tips Are Here




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