Unexpectedly hitting the wall

Morning,

I am doing the VLM this month and yesterday was my last big long-run - a 21 miler.

 I have run 20 miles three times in the trainging schedule I am following and managed it fine each time (coming in around 3hrs).

However yesterday I massively hit the wall at 18-19 miles which has scared the hell out of me. Energy levels dropped hugely and hips, legs, knees, feet - everything started to hurt badly.

The only thing different were that it was warmer than it usually is when I run my long runs - i drank about half a bottle of Lucozade during the run which is a little bit more than normal but not much. I had two energy gels too - the normal amount for anything over 15 miles.

 Any ideas as to why I crashed so badly? I am concerned now for the big day - I managed the last two miles at a proper snail's pace - 12 minute miles or so but I had nothing left in the tank at the end.

 My taper starts now so I should recover by the time the big day rolls round. I am training five days a week and have been since Jan (i am following the sub 4hr schedule that RW recommended on here).

 Any help or advice would be massively appreciated.

Hitting the wall is different to feeling off.  Hitting the wall is the point where your body runs out of glycogen and you would have found it incredibly difficult to carry on, if at all.

By the sounds of things, it was tough though.  When you say you drank half a bottle of drink, are you saying you drank around 150ml for a 20 miler?  That's way, way too little and probably answers part of your question.  I did my last long run yesterday and from start to finish I drank a litre of Lucazade and had water a few points too.  I also had a gel every 4 miles (Sis I think, but isotonic).  

What gels do you use?  If you are using non isotonic ones, and not taking water with them, then you are dehydrating yourself further as the body need water to process it, taking it out from your muscles to your stomach (at least, this is how it has been explained to me).  I used to use Powerbar but it's only fairly recently that I have notice you need to take 400ml of water with each sachet.

Other things to consider are what sort of training you had done over the days leading up to this run, how well and fed and hydrated you were over those days too and how hard you ran.

Sorry, no single answer as so much can influence a long run.  The main thing though is that you are not drinking enough from what I can see.

Sounds more like dehydration than anything else. I've had this happen often during my long runs as sometimes it's difficult to take on or find sufficient water. Shouldn't be an issue on the big day, so long as you drink often.

When doing long runs like this it's sometimes helpful to do circuits where you can regularly pass somewhere to replenish your supply.

I agree that it's probably dehydration, but it is very unlikely to be at all related to what you ate or drank during your run.  Dehydration happens over days and weeks; it's normal to experience some during heavy training, and you counter it by assiduously eating and drinking properly at and between meals.  Topping up with any number of colourful Lucozade products won't make the blindest bit of difference if you were running dry before you set off.

150ml is not "way way too little for a 20 miler".  You should be able to do training runs without the need for refuelling, and if you can't, you're not preparing properly beforehand.

Mark, and Badly Drawn Bloke, I'd suggest you read Noakes' Lore Of Running on these points, especially the extremely dubious statements that "hitting the wall is the point where your body runs out of glycogen".  It's certainly important to keep fuelled, but this idea that "the wall" is a matter of not eating enough syrup as you run is extremely misleading.

You shouldn't get panicked about your run.  Yesterday was the peak of your training and the point at which you'd expect to feel most worn out.  Obviously it would be great if it had gone well, but we all have bad days.

Thanks for help all. The amount I drank on the run yesterday was the same as I had done on previous runs of similar distance, I had never had any problems before. I never drink anything for less than 15 miles as I don't feel I need it. I could not drink much more without constantly stopping to urinate.

I had the High 5 energy gels - two in total, one at about 8 miles and the second at about 14. I don't know if they're isotonic or not.

I agree largely with Tmap that it is likely a combination of a bad day, it being very hot and sunny and not being hydrated enough. I normally drink several litres a day but this may have gone by the wayside in recent days. I certainly drank more than I normally do yesterday following the run.

 Any more advice is gratefully received. I am very keen to break four hours and, until yesterday, I felt very much on track to do so.

TMAP - I agree with all that.  I was just saying that Mark probably hadn't "hit the wall", just giving suggestions as to why his run hadn't gone well.  Eating and drinking sensibly leading up to a long run is essential.  I do fell that drinking half a pint of fluid on a 20 miler is too little though and I know I would really struggle on that.  Thanks for the heads up on the book - I'll check it out.

Mark - like you, I wouldn't bother with a drink usually on runs up to a certain distance, 13 for me , but would expect to have been well fed etc before and to recover after including drinking enough to replenish.

BDB - My reply sounds a bit stroppier than it was meant to be, reading it again.  I get tetchy at this idea that marathons are all about eating enough along the way - they're mainly about training.  The Noakes view, in summary, is that "the wall" is basically the point where your muscle cells lose elasticity and can't easily support your weight.  He also gets very angry at the "drink before you get thirsty" loons.

I'm not suggesting you don't need to eat or drink.  These days I can do them without even water but I can see that if I were able to eat while running it might be beneficial.  However, you often see it stated that if you don't re-fuel during the race you will Hit The Wall and it's not helpful advice, as it's confusing quite different things and encourages over-drinking and the stitches, cramps, and gastric unpleasantness that ruins many runners' races.

Mark - am intrigued by your "I normally drink several litres a day" comment.  Of what?

Worth making sure you're not over-doing it too; I guess that's possible, reading your post again.  I have a pint of squash when I get back from a run, perhaps two after a really big one, but otherwise just drink normally with meals.

That's 4.5 litres.

I'd guess I'm under 3 per day, unless you start to include an extra litre during a hard session at the gym (2 hours). I drink way, way more than anyone else around me, to the extent that people notice and comment on it.

Gosh.  That sounds like a lot - I'm not surprised that you can't take much additional sports drink without needing to stop. 

It would seem unlikely then that you were dehydrated before you started.  It's worth you reading up on hyponatremia too - you can over-do drinking water and it depletes minerals (especially sodium) in your blood.  I don't know what the guidelines are in terms of volume though.  You should look at that as it can be very dangerous.