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Mountain biking and insulin advice

Discussion in 'Fitness, Exercise and Sport' started by BeckiDover, Feb 17, 2019.

  1. BeckiDover

    BeckiDover Type 1 · Active Member

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    I’ve recently taken up mountain biking and I need some advice on how to adjust my insulin and/or diet to cope with it.

    In the first hour of mountain biking my bloods fell from 9.2 to 2.8. I was running my blood slightly high to cope with the exercise by having a unit less with breakfast and also had a unit less of my AM dose of levemir, but it still dropped dramatically and was quite difficult to bring back up!

    Would appreciate any advice anyone on here has! I also plan to discuss my healthcare team.

    Thank you!
  2. urbanracer

    urbanracer Type 1 · Moderator
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    I don't think there are many T1's around at the moment.

    I cannot think of anyone who's in to mountain biking specifically but I'll tag a few people who I seem to remember like getting physical now and then, @Juicyj @therower @helensaramay - and maybe you'll get some answers later.
  3. Scott-C

    Scott-C Type 1 · Well-Known Member

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    Hi, @BeckiDover , I've not been on a mountain bike for a long time but used to do a fair bit of cycle touring when I was younger.

    The details are a bit hazy now but I recall that if I was cycling for about 6 hours or so a day I'd seriously tail back bolus shots.

    A meal which would normally need about 6 to 8 units would come down to about 2. If it was a week long trip I'd also rake back basal by a few units too, not so much for short trips.

    The way the biology works is that when muscles contract during exercise, a protein called Glut4, glucose transporter, comes to the surface of muscle cells and lets glucose in without the need for insulin, so if you have your normal amount of bolus, you'll get a "double whammy" of both insulin and glut4 lowering levels, so it makes sense to tail back the insulin to avoid that.

    I found snacking on some jam on oatcakes and dried dates throughout the day a good mix of fast and slow carbs to keep things ticking over.

    Beware of "after-drop" too. Glut4 can carry on acting for a while after exercise, and your liver and muscles will be restocking the stored glycogen they used up during exercise, so that can drag you low after exercise too, so also consider smaller boluses for meals afterwards too.

    Have fun!
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  4. therower

    therower Type 1 · Well-Known Member

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    Hi @BeckiDover . Basically everything Scott has said above.
    Never really done mountain biking myself but have done a bit of road riding a few years back.
    Like most forms of exercise, distance biking can for me fall into two categories.
    1. Maintaining a steady pace over a set time, whether it be 1 hr or 5 hrs and for me that would result in a steady drop in BS.
    For this I would be looking to lower my bolus prior to the exercise. Early on in the exercise I’d be looking to have just a few carbs, malt loaf has always been good for me. Takes a while to kick in but provides a good source of energy. Bananas can be a good option as well.
    2. Doing short but intensive sprints or climbs. This type of biking ( probably far less likely to be doing on the open roads ) would see far less of a drop and maybe even an increase in BS. Really pushing your body , getting that adrenaline kick can cause big rises in BS.
    As an individual you’ll be best trying different things and logging down what works best for you and the type of ride you’re going on.
    Most importantly keep fast acting glucose to hand, stop riding until you’re sugars come back up. Cyclists don’t mix well with juggernauts. Once you’ve had something fast acting compliment with something more carby.
    Keep an eye on your BS levels after you’ve finished as Scott so rightly points out they can drop quite dramatically a few hours after.
    Most importantly though is DON’T stop your mountain biking and enjoy yourself.
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  5. Deleted Account

    Deleted Account · Guest

    I’ve done mountain biking a few times but not yet managed to optimise my BG.
    Going downhill, my BG tends to fall unless it is one of those tricky bits where I think I may fall. Then the stress causes my BG to rise.
    I am not so good at going uphill so my BG tends to rise.
    As a result, managing BG for mountain biking means frequent stops and tests but assume my BG will fall when I am having fun and rise when I am struggling
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  6. Wilko 2

    Wilko 2 LADA · Member

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    I mountain bike 2 - 3 times a week. What I find is that on those days I don't need basal insulin. I eat a porridge breakfast,with Chia and Coconut Milk. Im also experimenting with eating more fats at breakfast. Avocado, coffee with cream etc

    I carry a banana, nuts and stop for food if necessary. Test hourly and eat hourly to keep BG in range. With hard efforts, BG rises, but I know that it falls very quickly on stopping or going slower, so food is also vital, keep snacking on the ride. Slow acting carbs are good for this and I find Im better with these than fast acting. Im usually out 3 - 5 hours When I get back I eat normally but find I don't need Insulin until my evening meal
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