Hypoglycaemia?

[alp1950]

Interesting observation today. Newbie to road cycling and I've been building my distances over the last month. This week I've have ridden a total of 150 miles. Today, two thirds of the way through a 30 mile run which included a substantial climb I was aware of a mild sensation of disorientation. Difficult to describe, legs felt fine (ie no significant drop off in power) but slightly lightheaded so didn't feel quite so mentally sharp and perhaps a minor feeling of loss of coordination.

Stopped off to buy some (actually quite a lot ) of sweets and the symptoms settled. Since returning home I've had the munchies & have been stuffing my face. I suspect I was mildly hypoglycaemic & wondered whether this is a well recognised phenomenon in cycling?

 

[Fab Foodie]

Yep, it's well recognised, we call it the 'bonk' or 'bonking'. It's the point when you have pretty much exhausted your body's store of glycogen. Hence the craving for sugar... or the 'munchies' as it's known to replenish the lost glycogen.
The further and faster you ride, the more attention you need to spend on fuelling your body. The body can burn both fat and sugar, at lower to moderate intensities more fat is utilised in the fuel mix, at higher intensities the body switches to almost all glycogen. Make sure you have a good carb meal the night before the ride, a good breakfast and then keep nibbling as you ride. I can just about much manage 40 miles at a reasonable on just water when properly fuelled but will have a real crash If I dont get food on board pretty quickly... then I'll eat a whole candy store!

Either use an energy drink or keep nibbling something sweet from the off, jelly babies are good! Malt-loaf and Flap jacks are good slow-release enrgy foods favoured by cyclists. You'll soon find what works for you.

 

[Twenty Inch]

And don't drink too much coffee. The caffeine stimulates the pancreas, which produces more insulin, which removes blood sugar quicker, which leads to the bonk.

 

[yello]

You know, I don't think I've ever bonked. I say I don't think I have because I have felt pretty spent on occasions but nothing like the descriptions I've read of full on bonk.

I've done rides up to 250km, put in some pretty hard rides - by my standards - too (100km with 1200m climbing in a little over 4 hours, for instance) and I can't honestly say that I follow the rules to the letter for re-fuelling etc either. I have ridden 100's on nothing more than porridge for breakfast and 750ml of water.

So I reckon peoples' different body chemistries have a huge part to play in this too.

 

[domtyler]

I have bonked quite a few times, normally my own fault for doing fifty milers on half a bottle of water and no breakfast!

Last time it happened I was just passing a pub! Four pints of beer and large plate of sausage and mash sorted the problem but the ride home was still a struggle after that and didn't fee right again for three or four days.

Fortunately it is less likely to happen as you get fitter and more used to cycling long distances but, as above, it is possible for anyone to suffer if you do not take adequate measures to keep your blood sugar up.

 

[alp1950]

And don't drink too much coffee. The caffeine stimulates the pancreas, which produces more insulin, which removes blood sugar quicker, which leads to the bonk.

Touche.

 

[Fab Foodie]

Fortunately it is less likely to happen as you get fitter and more used to cycling long distances but, as above, it is possible for anyone to suffer if you do not take adequate measures to keep your blood sugar up.

This is very true. You'll learn to listen to your body's needs and also your body will become better conditioned to this kind of effort. A further good tipis a pint of milkshake as soon you get homew, best recovery product for almost no money, Nesquick and milk, fab.

 

[Abitrary]

Difficult to describe, legs felt fine (ie no significant drop off in power) but slightly lightheaded so didn't feel quite so mentally sharp and perhaps a minor feeling of loss of coordination.

I had a similar burnout whilst touring, doing about 60 miles a day, but my head / coordination was fine, but my legs just went, and it took me about 3 hours to get 10 miles to a hotel.... I just couldn't move them.

I reckon that is more in line with what the 'bonk' is perceived to be, and if I'm honest you should get yourself checked for diabetes. Are you overweight?

 

[Bodhbh]

my head / coordination was fine, but my legs just went.... I just couldn't move them.

I reckon that is more in line with what the 'bonk' is perceived to be, and if I'm honest you should get yourself checked for diabetes. Are you overweight?

General have what I've been assuming is the 'bonk' after about 60 miles, sometimes more than once on long runs if not shovelling down enough. Like Alp, for me the most notable thing is going very lightheaded, although generally physically tired too, it's the lightheadeness that makes me stop as it doesn't feel so clever to be riding like this in traffic when my attention to the road starts getting very slapdash.

 

[LLB]

Being Diabetic, I know a little bit about this. Nesquick works well because it is made from Glucose - the body doesn't have to convert it from other sugars found in foods like Sucrose, Lactose or Fructose.

Many Diabetics (and people working out very hard) get into trouble when they drink heavily as the alcohol suppresses the Liver function where the Glucose is stored as Glycogen. What this means is that they have a big night on the razzle and in the night their BG (blood Glucose) levels drop without the reserve capacity which the liver provides, and in their sleep they lapse into a diabetic coma (Hypoglycaemia).

Something similar could happen to a healthy person if they hit the bottle hard and did a 50 miler on their bike.

Flapjacks work very well for endurance because they provide an instant sugar hit with the syrup to get you going, and then provide the slow release carbs through the oats.

I have to keep a fairly close eye on the BG levels when cycling as I don't have the same ability to regulate as I should do, and feel the comparative drop in BG levels as I run highrer that a non diabetic without actually going into hypo (false hypo). I can also run very high BG levels and feel very tired as well as a lack of insulin doesn't allow the cells to take up the Glucose in the blood.

 

[peanut]

Last time it happened I was just passing a pub! Four pints of beer and large plate of sausage and mash sorted the problem but the ride home was still a struggle after that and didn't fee right again for three or four days.

thats the feeblest excuse i've seen yet for scoffing sausage & mash and quaffing 4x pints
Hope it was real ale and home made sausages

 

[domtyler]

thats the feeblest excuse i've seen yet for scoffing sausage & mash and quaffing 4x pints
Hope it was real ale and home made sausages

It sure was! Those first two pints were the quickest I have ever drunk beer in my life! Didn't even touch the sides. I could barely muster the strength to push my bike over to the pub and make it to the bar I felt so weak, I was almost grabbing the glass out of the barmaids hand before she had even finished pulling it!

Seriously, bonking is a pretty unpleasant experience, I was really lucky to have been where I was because it was really in the middle of nowhere, and a very hilly nowhere at that.

 

[peanut]

Seriously, bonking is a pretty unpleasant experience, .

its all in the technique lol


I occasionally get the shakes and wobbly legs in the mornings. I feel faint and very anxious ....weird!
I have to stuff loads of sugary stuff in my face pronto and its half an hour before I stop shaking and feel normal again.

 

[domtyler]

its all in the technique lol


I occasionally get the shakes and wobbly legs in the mornings. I feel faint and very anxious ....weird!
I have to stuff loads of sugary stuff in my face pronto and its half an hour before I stop shaking and feel normal again.

Tut! There's always one who has to drag the conversation down to the level of the gutter isn't there?

 

[LLB]

its all in the technique lol


I occasionally get the shakes and wobbly legs in the mornings. I feel faint and very anxious ....weird!
I have to stuff loads of sugary stuff in my face pronto and its half an hour before I stop shaking and feel normal again.

Pre or post ride ?