LCHF pushes my BS up when exercising

I have been on LCHF for about 4 weeks now. I have noticed that my BS go up during pretty much any exercise - aerobic as well as anaerobic. I went jogging today and my BS would go up by 1 mmol in just 10 mins of running.

When I went to play badminton the other day, my BS just surged and even kicked me out of ketosis.

In my pre-LCHF life, my BS would go down during exercise, not up.

It looks like I will have to bolus before exercise and that could end up really tricky as my BS could drop too fast during some intense activity.

So, I have two questions:
1. How not to be kicked out of ketosis during exercise
2. How to manage BS during an intense exercise such as badminton.

Any advice much appreciated.

Thanks, I have read 2 books by Phinney and Volek, really helpful in many ways but could not find a direct answer to my situation.

However, here is an update. I have just come back home from my Sunday badminton game(s). This time I took a bolus (just 1 unit NovoRapid) and let it peak before the game started.

My BS:
4.7 - before bolus
4.1 - bolus peak, 30 mins before playing
4.6 - 5 mins before game
5.4 - 10 mins into the game
7.2 - 30 mins into the game - here I discontinued because I did not want to get again to 11 like last week.

Next time, I will bolus again but try to let it peak in the middle of the game that lasts 60 mins.

I still cannot believe what is happening here - badminton is like a meal of pasta for me now

Thanks so much everyone for the insightful comments.

So, my understanding is the following based on your input: The glycogen stores in my muscles are rather depleted thanks to the ketogenic diet and so when doing an anaerobic exercise, my muscles badly request glycogen. The liver comes to help and dumps glucose into the bloodstream. Since I am T1, my pancreas does not counteract by providing insulin and so the muscles cannot effectively process the glucose and request more of it, the pancrease keeps dumping even more and my BS goes high. The only solution to this is to bolus before the game or switch to an aerobic sports activity.

Ok, so if I bolus and play badminton, my blood sugar should not go too high but I still wonder if I could be kicked out of ketosis due to all that glucose in my blood stream. Any thoughts? My guess is that I may be kicked out of ketosis but then perhaps the ketosis should come back again quickly thanks to the massive glycogen depletion. (see below)

And, by the way, here is an interesting account of what happened the first time I played badminton when in ketosis (about 3 weeks ago):
- I did not take any bolus with my low carb dinner and I also skipped my basal as the badminton game finishes at 10pm and I could potentially go low at night (my basal is still quite low, between 4 and 6 units of Levemir, so I can do this).
- But instead of going low, I went quite high - from around 5 to 11 during the game. I could not believe the meter as this was an absolutely new development for me. In my pre-LCHF period, I would have to eat a banana before the game and then drink apple juice during the game not to go too low.
- Equally interesting was what happened after the game. My ketones dropped to 0.4 immediately after the game but the next morning spiked to over 7! My BS went very low, I woke up with 3.9. I had to stop taking any bolus and basal for full 6 days after the game in order not to go too low. My fasting BS was consistently at 3.9, post-prandial around 5 and most of the day I was at 4.7. I am sure this was because of the total depletion of glycogen. My ketones returned to around 2 after about 3 days.

tim2000s said:

@cz_dave I've never heard of anyone getting the reaction you had which suggests you are still producing your own insulin to some extent (even though a very small extent).

Click to expand...

When I got my C-peptide tested back in March, it was in the normal range. So, I certainly have some insulin. It is just not able to compensate carb-loaded meals. But it can still compensate to an extent the glucose that my liver produces under normal circumstances (not when playing badminton, clearly).

So, while I am still in honeymoon, the combination of low-carb diet and sports activity has some interesting effects

Spiker, I think you nailed it.

I just got back from my Sunday badminton game. This time I bolused 30 minutes before the game and it worked out quite well. I started at 5.6, 30 minutes into the game I peaked at 6.8 and at the end of the game I went down a bit fast to 4.7, so I corrected with a sip of apple juice. Now I am at 4.5 and will probably have another sip of apple juice before going to bed.