FUELLING extended exercise

[gbs42]

I think that it is common ground that our natural body energy bank will typically support about two hours of moderate exercise and that thereafter fuelling up is necessary. Most sport drinks and energy bars etc are carbohydrate/sugar heavy and I am reluctant to consume. The context is typical is a bike ride 75k say 4 hrs of moderate effort. How do others plan for this level of output and the necessary input?

 

[Lucyr]

What happens to your blood sugars and energy levels 2 hrs in?

 

[everydayupsanddowns]

Welcome to the forum @gbs42

I’m going to tag-in @SimonP who lives with T1, rather than T2, but is a keen cyclist.

When I was distance running I’d always take rapid-acting carbs with me to top-up glucose levels after about 30-60 mins of running, alongside having reduced ‘insulin on board’ for carbs I’d already eaten (aiming for a gradually rising BG curve to offset the BG-reducing effect of the running).

Way back I used to post occasional videos about various diabetes-related things. This was an account of BG management (with T1) for a 10K road race

 

[gbs42]

What happens to your blood sugars and energy levels 2 hrs in?

I have never tested myself 2 hours into a ride. I occasionally suffer from hypoglaecemia but that is easily managed.

 

[Lucyr]

I have never tested myself 2 hours into a ride. I occasionally suffer from hypoglaecemia but that is easily managed.

How are your energy levels feeling at that point?

 

[SimonP]

@gbs42 are you on any blood glucose lowering medications? If not (and even if so, though you may need to change dosage in that case), then I'd probably fuel as per a normal person (but not a World Tour rider!) and start at the lower end with say 20-30g of CHO each hour. You could almost certainly get away with less though and probably skip any fuelling in the first hour or two without any undue effects.

I don't eat gels and the like, and prefer cheaper and more palatable (over longer duration) foods if possible - e.g. granola bars, biscuits, ham rolls (for long rides), Skittles if required for BG control and/or hills.

If I ride during the day I would typically tend to eat e.g. a Nature Valley bar (~25g CHO) about 2h into a ride, and then if it's a bit hilly will eat a mini-pack of Skittles (17g CHO) in advance of anything prolonged. For long rides it all changes and I will need to start eating fairly constantly (~60gCHO/hr) eventually (as well as reducing basal) after say 4h, but for <=4h the above would usually be enough.

In the morning I typically ride nearly fasted (a few cups of coffee with milk) to work (which is either ~20 or ~40km, depending on which location I'm heading to) and this is fine from the point of view of not needing to balance bolus insulin vs FotF + breakfast, however, it does mean I need to be a bit careful about power output and I'm not looking at setting records going up hills. I'd probably not start by doing this though, as it was pretty hard work to begin with!

We're all different though, but I'd be tempted to start on the lower end of carb intake and work up rather than vice versa!

 

[gbs42]

@gbs42 are you on any blood glucose lowering medications? If not (and even if so, though you may need to change dosage in that case), then I'd probably fuel as per a normal person (but not a World Tour rider!) and start at the lower end with say 20-30g of CHO each hour. You could almost certainly get away with less though and probably skip any fuelling in the first hour or two without any undue effects.

I don't eat gels and the like, and prefer cheaper and more palatable (over longer duration) foods if possible - e.g. granola bars, biscuits, ham rolls (for long rides), Skittles if required for BG control and/or hills.

If I ride during the day I would typically tend to eat e.g. a Nature Valley bar (~25g CHO) about 2h into a ride, and then if it's a bit hilly will eat a pack of Skittles (17g CHO) in advance of anything prolonged. For long rides it all changes and I will need to start eating fairly constantly (~60gCHO/hr) eventually (as well as reducing basal) after say 4h, but for <=4h the above would usually be enough.

In the morning I typically ride nearly fasted (a few cups of coffee with milk) to work (which is either ~20 or ~40km, depending on which location I'm heading to) and this is fine from the point of view of not needing to balance bolus insulin vs FotF + breakfast, however, it does mean I need to be a bit careful about power output and I'm not looking at setting records going up hills. I'd probably not start by doing this though, as it was pretty hard work to begin with!

We're all different though, but I'd be tempted to start on the lower end of carb intake and work up rather than vice versa!

Thanks for yr comment and practical notes - in the context of longer rides the 60g /hr parameter is particularly helpful. All best, GBS

 

[SimonP]

Thanks for yr comment and practical notes - in the context of longer rides the 60g /hr parameter is particularly helpful. All best, GBS

My requirement for 60gCHO/hr is only related to maintaining BG due to the presence of long acting (basal) insulin, which I can't really reduce much further very easily due to the changes in insulin sensitivity after that sort of duration of riding (I still need it doing something for the first half of a ride). I definitely don't do this until more than 4h into a ride (as I'd go high), and even then I do try to avoid needing to eat this much while riding as digestion is slow when exercising and I'm typically not overly hungry - I find it much more pleasant to ride 100km (with an on-bike snack en-route) then stop to eat something sitting down, then ride back with the food from the stop at least partially delaying the inevitable drop in BG.

So it's not related to nutritional requirements (for which even that amount of food is probably under-fuelling, though this isn't necessarily a bad thing if one is burning predominantly fat while riding) and I don't know how useful it is for someone who's T2 - when experimenting with basal reductions I did some 5h rides without being able to eat anything (BG pegged at ~9 mmol/l) and it was mildly unpleasant towards the end riding up hills as my legs felt empty (I didn't want to take bolus as I'd then get a massive drop in BG and at that point these were quite a long rides for me so I wasn't really feeling much like eating by that point. I would now stop take some bolus if required and eat rather than soldiering on without food for so long).

If I weren't taking insulin or something else that drops BG (are you?) then I'd be very tempted to keep riding until uphill performance took such a dive that I decide I needed some food to perk me up, and then work backwards from there what the hourly rate should be.

If I weren't diabetic I would guess I could happily get away with say 20 - 30gCHO/hr to keep me going on the bike indefinitely, assuming I always ate a decent quantity of food in the meals before/after riding (allowing me to top-up any calorie-deficit in a more enjoyable form), and also ensuring I drank sufficient beer to rehydrate and get some extra calories in 🙂

 

[The_Bowlii]

Hi all, it’s been a while!

I agree with what @SimonP says above - I took his advice when diagnosed with T1 and, with some trial and error, am now in a happy place when cycling. Typically, I do long rides with normal basal plus normal bolus for breakfast and top up with a Nature Valley, banana or Fruesli bar just before heading out. This keeps my BG steady for the first hour or so and then I eat 20-30g of glucose an hour, usually through a jelly baby or two every 15 minutes. If I stop for a coffee and cake, I don’t need to take bolus insulin as long as I’m moving again within 10-15 minutes. As long as I pedal for another 2 hours or so after this, I remain relatively flat and within range (~6.5 mmol/l) until I get home.

On the bike is when I feel most in control so it means I now do more cycling which is a winner!