This topic contains 13 replies, has 3 voices, and was last updated by Anonymous 4 years, 6 months ago.
5 September, 2013 at 7:40 am #15460
Sorry.. couldn’t resist.
I’m still feeling like a noob with my pump and need suggestions for my sports basal adjustment. Technically I could probably ask my doctors, but their reply is (as always, correctly) going to be: You’ll need to find out for yourself. Which is all well and good, but I want a starting point somewhere.
So … cycling. I do cycle a bit, and the basal rate seems to be fine in the mornings with or without sports (meaning: I don’t change in on the weekends, when I stay in bed lazily, and don’t get any highs). When I get to work, my sugar is typically near the lower end of my acceptable range (90-110mg/dl for me … but we use different units. 5-6.1mmol/l if my internet conversion thing is right). This is the time affected by my breakfast (decent meal with about 60g of carbs) and the breakfast bolus (reduced by 20% for following sports).
However, in the afternoon I obviously don’t have a second breakfast (hmmm…), so the only option so far is to reduce my basal rate. I aim for “half an hour before, -20%”, grab a drink of juice before I head out (25g of carbs) and drop from a sensible blood glucose level (say 5.5mmol/l) to something entirely indecent when I arrive (say 2.2mmol/l).
Obviously too much insulin. Easy so far. As I don’t adjust my basal rate in the mornings (at all), it would appear the mornings are covered by the breakfast and breakfast bolus reduction. Which is rubbish. Now I don’t know what would happen without brekky and I have lows in the afternoon. Any suggestions on how much further to drop basal rate in the afternoons?
Insulin used: Humalog (one of those high speed insulin-analog thingies)
Sports used: Cycling at ~18-20mph average speed, heart rate >150, peaking >170 for more than 2 minutes. Typically too tired for max puls sprints in the evening.
5 September, 2013 at 3:35 pm #15461
As always, your diabetes will vary, but when I go out on the bike I drop my basal down to about 10-15% about half an hour before I go out (if – and it’s a big if – I remember). I will then knock a bit off my next bolus. Not very scientific but it seems to work.
During the Roman Rumble (when I cycled across Britain) I had a 10% basal during the day and put in 1-2 units of bolus for breakfast and lunch. It was as if I was cured!
9 September, 2013 at 7:06 am #15462
Doubly, in fact, because not only was that a suggestion value that seems interesting (I tried 50% last friday, which was still too much – blood glucose dropped from 11 to 5.5), but you have somewhat given away that you’d know long distance cycling.
So …all my Paris-Brest-Paris questions will now be headed your way. Sorry 🙂
9 September, 2013 at 12:48 pm #15463
He he! More than happy to discuss cycling & diabetes all day long! 🙂
9 September, 2013 at 2:52 pm #15464
Now I just need a way to sneak Diabetes into every bike-discussion. Possibly by starting my posts with: I tested my blood glucose just now and found I had a 9.3mmol/l. Now I have trouble deciding wether I am allowed a mountain bike along with the road bike and the rando-bike. Help me convince my wife that three bikes are not too much! 🙂
9 September, 2013 at 4:21 pm #15465
The one (and only) advantage about running your own diabetes web site is that you can discuss what the hell you like – so it’s cycling all the way! @alison may object but it won’t be first time we’ve bitterly, bitterly argued*
I think you should get a mountain bike. I got one last year after being a committed road bike person for years. As I live on the doorstep of the Pentland Hills there are tonnes of good tracks within ten minute’s ride, so it seemed silly not to. Mountain biking is a different discipline and I find the style different from road-biking but it’s bloody good fun.
As my starter bike I went for a Specialized Hardrock – it’s not particularly rugged and as a result I keep breaking it but it was relatively lightweight (though about three tonnes heavier than my road bike!) and relatively cheap. If I was buying again, I would probably save up a few more hundred pounds and go for something tougher.
* this isn’t true by the way.
10 September, 2013 at 8:52 am #15467
I bought a cyclocross race-bike last winter, as I finally had to admit that slick tyres don’t work all that well on snow and ice. Which is probably more than a little stupid, as new tyres might have done the trick, but I blame that on something else. Sleep-deprivation due to little child, maybe … or onset of old age. Or something.
However, it looks like there might be enough room in the shed for a roadbike and a mountain bike. The bicycle test said I need a “touring fully”. Which only helped a little bit, if I’m honest – but I accept and appreciate that I’m not looking for a downhill racing bike. Luckily, we have (at least) two rather good bicycle internet shoppy things over here. Their bikes are usually tested as “bloody brilliant” and they are a LOT cheaper than the ones in the shops. With the obvious drawback that there is no local salesperson you can beg to fix it all. Components are usually about two grades higher than what you get for the same cost in the shops, though.
And … it seems my wife actually supports another bike. Which makes me wonder – does she want me out of the house? (<- this also isn’t true :).
10 September, 2013 at 10:41 am #15469
Part 2: 400km Brevet “Around northern Bavaria”
Insulin: Levemir and Novorapid, ICT with two Levemir injections (mornings and evenings).
The second brevet this year was supposed to be a longer distance. I had skipped the 300km one due to family obligations (they did not want to postpone the wedding so I could go cycling *sigh*). The results were “interesting(tm)”.
The start was set for Friday evening (20.10h), and the time limit for the 400km is 27 hours. Which meant that even the slowest cyclists have to be back at the start by 23.00h Saturdays – in time to catch the last train to civilisation and allowing the organizing people to actually go to bed eventually. The weather forecast said “cloudy, likelyhood of rain 60%” – which technically only applied to the location of the start/finish and the distance was too long to check everything in advance. So I packed a jacket and some spare socks.
As the Friday was a normal work-day for me, blood glucose and insulin both were “normal”. My lunch meal still had the normal bolus. The goal: a normal blood glucose level for the starting time and then a large dinner before heading out . Interesting (and I still don’t know what happened there) was the train trip to the start (around 18.00h). Blood glucose kept rising without additional carbohydrates. When I arrived, I had a blood glucose of 420mg/dl (23.3mmol/l) – which is not what usually happens on Friday evenings. Honest! I check! I can only hazard a guess: Stress, because of the unusual event caused my sugar to rise. Which would fit the previous event.
The first order of business was a correction dose of insulin then (6 I.E. for the theoretical reduction of 420->120 mg/dl (23.3->6.7mmol/l)). The dinner at the start I obviously did not skip (Spaghetti), but I used only 50% of the normal bolus for the carbs. The evening injection of Levemir was also on time – and I reduced it to 70% of normal (slightly less than last times 75% basal rate, which is mostly due to “even numbers only by pen”). All this lead to a remarkable 530mg/dl (29.4mmol/l) at the starting time – no ketones, so I did the same as last time and ignored it.
The start was brilliant. I found a group of fit road bikers, who dragged me along in their slipstream. The first 65km (40 miles) flew past at a speed that was apparently too high for me. At the first hill after that I got dropped. Hard. My puls was too high, my strength was gone and I bonked. As the group had reached the top of the hill anyway, I thought this would be a good time to test. Bllod glucose at a near-perfect 130mg/dl (7.2mmol/l). After one hour, 45 minutes. So I started to eat and drink (which I may possibly have neglected in the previous 2 hours – and which sufficiently explains the bonking ).
Unfortunately the lack of liquids lead to problems on the next 60km (40 miles). Cramps in the calves and thighs, lack of power and generally not feeling well. See , really. I can do better. Someone caught me up, though, and gave me some help and tips (like: the water on graveyards in Germany is drinking quality and can refresh both flowers and cyclists. Especially at 02.00h in the night in the middle of the countryside, where pubs are … sparse).
In total darkness I finished the first 200km (125 miles). With a slightly slower group – who caught me up somewhere on the way. After 120km (75miles) and 200km (125miles) my blood glucose was in the range of 100-130mg/dl (5.6-7.2mmol/l). Provided I was continuously feeding myself with bananas.
A fabulous stop at the 200km control: We got to a small McDonalds on the side of a motorway (by the back entrance – we didn’t cycle on the motorway!). They had two people manning the restaurant in the early morning hours (we arrived around 05.00h). Around 100 cyclists, clad in various amounts of lycra, sweating and hungry, arrived over a few hours. When the first 20 or so reached the till and asked for fries with lots of salt, the girl at the till showed proper foresight, looked at the rest of the group queueing to the outside and flipped on all the deep-friers.
With the break of dawn we reached the Frankonian hills. My morning basal rate (Levemir) was reduced to 75% (again – a problem with the units in a pen) . I didn’t need any bolus insulin any more, though. With a relatively constant blood glucose I continued till the early afternoon.
After about 18 hours I had to give up (kilometer 360 (225miles)). Apparently I lost so many minerals during the night/day, that I started getting cramps again – and eventually my brain decided that enough was wnough .
Interestingly, the recovery was not as pronounced this time. I reduced the basal rate to 70% again the following evening but already woke up with a slightly raised blood sugar the morning after. Definitely better than a night-time low, though.
Good things, though – the DNF was not due to my diabetes (which is nice), but due to over-excertion on the first part and not enough drinks while cycling. Could have happened to anyone.
The highlight were without a doubt the 1000g of carbohydrates that I got to eat without injections. In retrospect this obviously means that my basal rate was way too high. As the sore muscles have returned to normal, I’m looking forward to the next event, though.
 This still sounds like a good idea. I don’t need highs during the day before that reduce my power and send me to the loo all the time.
 Due to my lack of experience with long distance cycling, I’d say. All of this was new for me this year and I make mistakes. Stupid mistakes, but mistakes.
 I normally use 4 I.E. in the morning. 2 seemed too low, 3 is a bit too much. The new pump will make everything better. Room for improvement, though.
 “I do not want to cycle up that hill” and “I’m slowing down my group – they are all much fitter than I am” was what I was mainly thinking. A long break at this point would probably have done (and in fact I felt much better by the time my summoned sag wagon (i.e. my wife) arrived). However, the little village we were in at the time when I stopped wanting to go on didn’t even have a restaurant/pub/anything. It would only have been 10 more miles to the next control with a large spread of food. I need to work on mental toughness, it would appear.
10 September, 2013 at 1:55 pm #15478
Epic posts there @Flo123! I enjoyed them!
11 September, 2013 at 8:08 pm #15480
Not sure if this will be useful for you super-cycling heroic types, but I found a good website that suggests how to adjust extra carbs/insulin reductions for exercise: http://www.excarbs.com/
Interesting basic suggestion is that you should aim to replace 1g of carbs for every kg you weigh per hour. (So a 70kg person exercising for 30 mins should take 35g extra carbs or compensate for that amount by reducing insulin). They get more technical than that but I’m looking at the easy options first! Haven’t tried it out yet of course…
12 September, 2013 at 9:23 am #15481
That looks interesting – though the maths looks insanely complicated. I struggle with basic arithmetic at the best of times…
13 September, 2013 at 8:39 am #15483
Naha! Actually it’s even easier and better. I (or rather http://www.excarbs.com/ ) calculate my cycling on a brevet to use 65-70g of carbs per hour. I can supply this by a combination of reducing basal insulin and eating, eating, eating.
This is total genius.
For my post-work-home-sprint, I apparently need 80g of carbs per hour. Which makes sense, as it’s more intensive, as it’s shorter.
This is total genius again.
I understand it now. I think. Practise to follow on monday (independent of weather) or the weekend (if it’s sunny).
10 September, 2013 at 9:42 am #15468
Before this all goes completely off-topic (the diabetes topic, that is), I thought I’d share my bicycle cycling experience on the two brevets I did this year. Complete with insulin types used and stupid mistakes made and everything. Might come in handy for someone else looking into it. Possibly. At least I’ll be a bad example.
Part 1: 200km Brevet “Along the Altmühl River ”
Insulins: Lanthus basal, Novorapid bolus. ICT with one Lanthus injection in the evening.
The trip started on a fine Saturday morning. I reduced the basal injection the night before (around 9pm) to 75% of normal . The morning after I had to get up at stupid-o’clock to travel to the starting point. A large breakfast with loads of tasty carbohydrates was consumed – with slightly more Novorapid to cover for the lack of basal insulin. Morning blood glucose wasn’t too bad, actually, which surprised me with the reduced basal rate. After that: cycle to the train station, hop onto a train and check the blood glucose levels, approximately 1.5 hours after breakfast – a duigusting 220mg/dl (12.2mmol/l) was the result .
Commence heroic correction (yes, that was stupid)! Meet up with all the other strange people, who enjoy cycling until it hurts, for a common breakfast at the starting line. Another blood glucose test found 80mg/dl (4.4mmol/l). Which I considered a bit low, just before sports. The correction for the “low” consisted of three pieces of cake – without a bolus injection, which turned out to lead to a high blood glucose during the morning – which isn’t that surprising, in hindsight).
Start of the actual event was at 9.15h in a large group of cyclist in front of a backdrop of black clouds, sunshine and a strong tailwind. Up to the first control (places to stop and get a stamp at – to prove you went the right way) I then had to keep correcting my way too high blood glucose (I used Novorapid at 1 I.E. per 50mg/dl(2.8mmol/l) reduction – which is identical to what I use outside of sports ). I attempted to test my blood glucose on the bike with the Accucheck Mobile taped to my top tube – which didn’t work. At all. The lancet device requires two hands. We did, however, stop occasionally allowing me to test. For the record: The highest blood glucose tested during the beginning of the event was 500mg/dl (27.8mmol/l) .
After roughly 75km (46 miles) my blood glucose had dropped to 120mg/dl (6.7mmol/l) and no further corrections were necessary. The speed at which we were travelling was set to about 24km/h (14 miles/h) – brevets are not a race, more of a friendly cycletour – so I felt quite happy at this blood sugar levels.
At that time, I fell back to my normal feeding plan for cycling. Which is not ideal for weight loss, but I’m all for the “can’t have everything” motto. Approximately every 45 minutes I consumed 40g of carbohydrates in varied shape and form (all of them relatively quick: bananas, dates, coke, sport-gels) and at every control (~ every 40 miles) I added something savoury. Typically a cheese or ham sandwich, so I wasn’t forced to eat sweets all day.
The good news: blood glucose stayed stable for the rest of the day. Between 105mg/dl and 130mg/dl (5.8-7.2mmol/l) – which apparently means I did everything right!  An interesting (and not diabetes related) problem in the afternoon: We stopped at a supermarket to get a cup of espresso and I grabbed a bottle of Strawberry/Banana-Smoothie instead of the juice I had had in mind. This is drinkable from a bicycle bottle (barely), but it’s not ideal. At all.
There were problems, of course. A crash in our group forced two to quit due to damage to the bikes (too many broken spokes on one, a broken brake lever on the second bike). A few hailstones fell on our jerseys in the early afternoon, when the thunderstorms caught up. My elbows started to hurt (at around the 150km mark (95 miles)) and my bottom complained (starting around the 175km mark (110 miles)). Any climb over 18% (luckily there were only two) was not much fun – especially in my weight class.
Useful side effect: I noticed that my Lanthus dose worked for almost exactly 24 hours (this is apparently sometimes debatable). After 24 hours 15 minutes my blood glucose started going up, which I covered with more food and some extra bolus to prevent complete lack of insulin.
The recovery period lasted for about 8 hours afterwards – with a still reduced insulin amount (again: 75% Lanthus) and more food (which I was quite happy for at that time, I’ll freely admit).
Total time for the 232km (144 miles) was about 13 hours. With plenty of breaks and a lovely group. The plan for the next ride was to go about everything a good bit more relaxed and to not correct too much (in both directions – cake and starting sugar).
 A Lanthus problem. As the period of effect is 24 hours, I need to reduce the basal rate long before the sport actually started. This obviously leads to high blood glucose levels in the morning. This got better on the next attempt, using Levemir, and should not be a problem any more with the pump. Yay for technology in this case!
 Yes, I should have known this was only the post-breakfast high and that the breakfast bolus was still working. I probably was just too tired (or stupid, but I shall heroically ignore that possibility).
 And this is probably too high. Not recommended for imitation.
 General consensus is: this is too high to do sports. I could not detect any ketones and actually felt good, so I continued. I would definitely recommend against this, though. Blame it on my stupidity.
 Lest this sounds too impressive. I got lucky. My group also had a work collegue (who cycles a lot more than me and who’s got plenty of long-distance experience) and his wife (who cycles a tiny bit slower than me). They set a pace that was ideal for me with only minimal exertion. This was probably perfect for my “diet plan”. Next time I’ll be on my own and will have to eat more, as I’ll probably not be able to pace myself as well.
 Oh “Along the river”? A horrible LIE! The part along the river (which is by definition relatively flat) was limited to about 32km (20 miles) – the rest was a bloody up and down the surrounding hills.
13 September, 2013 at 8:21 am #15482
Thank you for the link, Hilary.
Edit for clarity: Everything below the line I’ll draw is my napkin math and can probably be safely ignored:
From what I’ve seen so far: I managed a combination of eating 60g of carbs per hour and reducing bolus for another 5g of carbs per hour (tentatively – my math is dodgy there). This is very very close to what they calculated for a 90kg athlete (which wasn’t all that wrong, if I’m generous) as the maximum edible. I will personally aim for 65-70g of carbs per hour for long distance events in the future, but I will try to get more of that from basal reduction and less from food. It’s ridiculous to have to eat that much.
(^ that there is the line I drew. Anything from here on is probably useless).
I’ve bookmarked it and will check it back after the next longer ride to see if it holds up. Might as well use the forums for some napkin math, because I usually work better with my numbers than generalisations.
Recent experiences of mine (been testing since we started this post):
Example 1: Start at a blood glucose of 200mg/dl (11.1mmol/l), reduce basal rate half an hour prior to sports to 30% of normal (reduction by 0,6 I.E./hour) for 1.5 hours (so 0.9 I.E. less than normal in total), eat 36g of carbs 1 hour before sports, using 20% less bolus (in this case: 3.6 I.E. normally are reduced to 2.8 I.E.). Give a bolus to reduce the 200mg/dl (11.1mmol/l) down to 100/5.6 – my designated target. Use 20% less than normal for this due to the following sports (1.6 I.E. instead of 2 I.E.).
After 30 minutes of vigorous cycling (which is not in the list, but we’ll guesstimate later), blood glucose drops to 50mg/dl (or 2.8 mmol/l).
Example 2: Start at a blood glucose of 200mg/dl (11.1mmol/l), reduce basal rate half an hour prior to sports to 20% of normal (reduction by 0.7 I.E./hour) for 1.5 hours (so 1.05 I.E. less than normal in total), eat 36g of carbs 1 hour before sports, using 20% less bolus (in this case: 3.6 I.E. normally are reduced to 2.8 I.E.). Give a bolus to reduce the 200mg/dl (11.1mmol/l) down to 100/5.6 – my designated target. Use 20% less than normal for this due to the following sports (1.6 I.E. instead of 2 I.E.).
After 30 minutes of vigorous cycling (which is not in the list, but we’ll guesstimate later), blood glucose drops to 100mg/dl (or 5.6 mmol/l).
Result 1: Ignore Excarbs limit of 50% [here: http://www.excarbs.com/insulin-injections-pumps-and-exercise/ ] (in my case only – I think it’s a good starting point).
Result 2: 20% seems the way to go for a fed and watered, high starting glucose. Adjustments and meal boluses of 80% are good.
Long distance comparison guess:
I have to guess here, as I don’t have the proper numbers any more. I used a basal rate of 70-75%, and I have to pretend that both Lanthus and Levemir are smooth (otherwise I can’t calculate it). That gives me a reduction of:
Case 1: (4-1=1I.E. per 16 hours for daytime dose of Levemir) -> 0.0625 I.E./hour
Case 2: (12-3=9I.E. per 16 hours for nighttime dose of Levemir) -> 0.5625 I.E./hour
Case 3: (16-4=12I.E. per 24 hours for dose of Lanthus) -> 0.5 I.E./hour
Result 1: No wonder the pump makes things easier. Those doses are off by a factor of 10!
Result 2: 1 I.E. of insulin accounts for 10g of carbs, so if reducing my basal rate by 1 I.E. accounts for 10g of carbs less eaten (that sentence makes my head spin – sorry. I’m a foreigner), then I basically accounted for 5g of carbs per hour with my insulin (no wonder it wasn’t enough on it’s own).
Result 3: The only number I have nailed down is 1000g of carbs over 16.5 hours (which is the total time before DNF on the second attempt minus the two hours of no-food at the beginning). This comes out to 60.6 grams of carbs per hour. Which is very close to what they calculated here: http://www.excarbs.com/adjusting-carbohydrate-for-exercise/ .
That was the number I could squeeze into myself without bolusing by eating as much as I could keep down. It included two rest stops at McDonalds (where I’d usually eat more, but that time barely managed two large fries and a half eaten hamburger plus two cokes at the first stop and two breakfasts plus two cokes at the second), two petrol station with a sandwich and coke each and loads and loads of bananas and cycling type gel foods. I think they are pretty much spot on with “you cannot eat more than 60g of carbs an hour”. Next time I’ll reduce basal rate more, though.
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