Dan, I don't get my information off the side of packets but from academic sources. You haven't quoted the sources you cite correctly - Mike Stroud's book (Marathon of the Sands chapter) explains why sports drinks hydrate better than water. www.runnersworld.co.uk can probably direct you to plenty of other academic sources, not to mention plenty of anecdotal evidence in the forums. 1986 is prehistoric in sports research terms, so you'd be better off looking at something more up to date.
You're quite correct that "Polymer sugars - those made up of several glucoses joined together, such as fructose maltose etc - are better than glucose" for several reasons. Go gels and PSP22 (and probably most other brands' similar products) are basically a type of maltodextrin which is 98% in this form, a far greater amount than any 'natural' food, and so much more readily taken up and utilised. For regular activities, of course a whole food is better, but working near your limits for extended periods means your energy needs are different, and you need to supplement your regular meals while you're on the move.
I now know why I don't use them. I can't afford the time to take the degree needed to understand what you're imbibing. Can't wait until Dan comes back from the library...
1. Eating gels - rip the top off with your teeth, the gunge then goes in your mouth. Nasty but effective. It'll still get on your fingers somehow, but ripping the sachet open with your fingers is a passport to disaster...
2. Joan, if you've not already got it, you should take a look at Twight's book 'Extreme Alpinism'. It brings all this stuff together and applies it to climbing use along with a load of other useful gen.
3. Whatever the research shows, for me at least, at medium intensity - eg mountain biking, running, fast alpine mountaineering - a sports drink (not an out of the bottle one like Lucozade btw but powder added to water like PSP22 or High5 Energy Source) is more effective than a combination of plain water and snacks.
4. Tea/coffee a nightmare diuretic - I'm planning to wean myself off caffeine before next big trip simply so I can alpine start without tea.
5. The science doesn't really matter Mike, it's more that in some circumstances, sports drinks and gels work better than plain water and proper energy bars are an effective way of carrying an optimum snack around with you. You don't really need to know what your blood or muscle/liver glycogen is doing for it to work.
6. Back to muscle/liver glycogen. Once you've eaten this, it can take days to replace and can't be topped up while you're exercising. This is why it's important to take it easy early on as hard, anaerobic effort eats it as the main fuel. Once it's gone, you're reliant on fat burning, which in turn needs glycogen to happen. Again you don't really need to know why, just don't go bananas early on a long route or you'll know all about it later on. The other reason not to do this is that if your system isn't well adapted to handling lactic acid, your muscles won't absorb oxygen as efficiently after a hard effort.
I like Isostar for drinking - at half the recommended concentration. It's a bit strong and expensive at full concentration. It comes in tablet form which is very handy, as I can pop a few into my water bottle after each refil - much tidier than a powder. I'm pretty sure that I get a genuine benefit from the salts and carbohydrates in it - especially when I've been sweating up a hill for a couple of hours.
It also covers the taste that Iodine tablets leave after they've killed all the bugs.
First must admit to having an old vested interest as i used to be the guy who looked after the Clif Products when they were in the UK.
So I've had this chat many a time at trade shows, events etc.
The key to all these products is finding what works for you. The only way to do this is to go out and try things. Not going into the science some things work for some people but it varies from person to person.
Most importantly before you reach for bars and gels make sure you are hydrated - this is the biggest reason for starting to fade.
Thanks Rob. It's a shame the Clif stuff's no longer available here as it was far and away my favourite energy bar and gel and no wind either. I won't ask the obvious question about why you stopped importing, since I guess it was simply because you didn't sell enough product to make it viable, but if you know of the whereabouts of a secret stash of Mocha Shots, I can make it worth your while ;-)
Oddly - and this isn't corporate spin - Clif was a victim of it's own sucess in Europe. Demand outstriped supply in the USA, Canada and Europe. They therefore decided to concentrate on home markets and fufill demand there. The production of bars can not be easily out-sourced (for instance Clif products are made in a kosher env. amongst other horribly complicated reasons).
Oh and as far as I know there are no Clif Shots left in the UK which will be within use by date.
So Clif Bar Europe sort of ate itself. Shame really - suggests there's a market for someone to get out and exploit though. SIS and High5 stuff works well enough in my experience, but Clif Bars actually tasted like something you'd want to eat rather than something you had to. Oh well... A trip to the States it is then.
Not what we wanted to hear, Rob, but thanks for the info anyway. I wouldn't have even started this thread if Clif stuff was still available here. Glad to hear they're still going strong in the States though
They also make a women's specific bar called 'Luna', that might be subtle reference to the Tales of Eva Luna or may be something to do with, erm, whatever.
This is interesting/bloody obvious. except one journal artical a theory does not prove.
TI: Title Effects of three hydration beverages on exercise performance during 60 hours of heat exposure.
AU: Author Meyer LG; Horrigan DJ Jr; Lotz WG
SO: Source Aviation, space, and environmental medicine, 1995 Nov, 66(11):1052-7
AB: Abstract Without adequate hydration, profound heat stress and dehydration can occur in people who work in hot environments. This study evaluated the effectiveness of three beverages on temperature regulation, cardiovascular response, and work performance during 60 h of dry heat exposure. Volunteer subjects lived in a climatic chamber in simulated desert conditions varying from 25-45 degrees C at 20% relative humidity. They performed three submaximal exercise sessions on a motorized treadmill at 4-h intervals each day. All of the subjects consumed one of three beverages: a water placebo, a 5% carbohydrate-electrolyte drink, or a 4% carbohydrate-electrolyte drink containing 1% glycerol, during each 60-h session. During exercise, the rating of perceived exertion and heart rate were similar for all beverages and all sessions, but oxygen consumption, core body and average skin temperatures, and sweat rate differed among beverages and sessions. Water alone appeared to provide adequate hydration for working in desert conditions over the 60 h when compared to carbohydrate-electrolyte beverages, with or without a small amount of glycerol.
hmmm - OUTPUT perspiration = salt loss (or electrolyte loss)+ water loss
INTAKE water
over time (remember your salt solution filling a vat A level maths?) there will be a reduction in electrolytes. Whether the reduction is critical or not would be dependent on several other factors for example individual tolerance, start levels, finish levels and so on.
I still like me olives. BTW those sports drinks really do seem to work especially when you most need them!
I thought I was the only one who ate olives while exercising (only low intensity stuff).
Cheers for the good words about Clif stuff. Luna Bars are great (both in terms of taste and science).
Oh and Clif are the only company I know have not one but two climbing walls in the head office.
Would recommend clif bar web site for technical information on this thread - you obviously have to accept the fact it's more than a touch biased. the power bar one is great too.
Seeing as we are all expressing opinions I use SIS stuff now.
Crikey. Just waded through these posts, plenty to think about, and lots of good advice... For what it's worth: a) Like everyone else I have fond memories of Clif bars. And indeed having accidentally consumed a luna bar before realising it wasn't for boys I can report that the lemon flavoured bar was delicious. (My breasts have remained unchanged in size subsequently). b) UK favourite easily available cheapo bar was the apricot organic Geobar - way ahead of dry crumbly obnoxious Nutrigrain offerings. A good, moist bar readily eaten on the go and with plenty of complex carb, plus it tastes good. c) I deal a lot with nutrition and fluids, but we tend to stick it down peoples noses via big tubes, or straight into their veins, and generally it's in the context of critical illness. This invariably means that metabolic handling eg of a carbohydrate group is subtly (or even grossly) different from a normal well human being. So although interesting (well a bit) it's absolutely zip use for this subject! d)for reasons of paranoia mainly I always make up sports drinks about 5-10% too weak: especially out in the field it can be difficult to get the proportions right, and the dangers of making them up too strong are clear. Too weak may not work quite as well (though I have to be convinced about this yet) as just right, but too strong really can make things much worse...
I like Geobars too, but the local Tezzies has just stopped stocking them in favour of some skanky own-brand things. Also concur on mixing concentrations, I usually run mine on the weak side of optimum - I've got it wrong, in the past, at altitude and it's not a good move.
Having had a good trawl through the lit available on the net (not much admittedly) it seems that:
As long as you drink something and eat something in sensible amounts you can maintain your performance for longer.
What it is - plain water, sports drink, maltloaf, whatever - makes no perceptible difference. Of course, if you like it, you'll want to eat or drink more if it.
Have a read of this, an abstract from the British Journal of Sports Medicine:
The hydration and electrolyte maintenance properties of an experimental sports drink J White and MA Ford
Seven highly trained subjects underwent exercise dehydration without fluid replacement (X), resulting in approximately 1.9% and approximately 3.5% body weight (fluid) losses at one and two hours, respectively. Subsequently, subjects underwent two identical exercise trials with isovolumetric fluid replacement of water (W) and an experimental formulation (Q). An anti-dehydration schedule was initiated prior to, and continued throughout the exercise, with W and Q supplied every 15 minutes at 16 degrees C in volumes related to each subject's fluid loss estimate derived from trial X. A rehydration schedule was maintained for two hours of recovery, with total fluid replacement equivalent to the body weight decrement due to fluid losses. In both W and Q trials, selected physiological indices of work performance were maintained closer to homeostatic levels during exercise, with a more rapid return to pre-exercise resting levels during recovery than during that trial X. Furthermore, W and Q were equally effective in preventing plasma volume changes during exercise and restoration to pre-exercise levels during recovery, as well as in preventing plasma osmolality disturbances during exercise and recovery, although minimal plasma electrolyte changes were associated with Q.
Me again: Sure it's old, but the methodolgy seems sound enough.
Oh and an interesting bit about caffeine I found:
THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 11 - NOVEMBER 97:
Caffeine and Hydration
Caffeine also has a diuretic effect--that is, it enhances urine formation, often causing a need to urinate within an hour after consumption. Yet two studies with subjects who took caffeine before they exercised (1,2) showed no detrimental effects on hydration during exercise. Thus it appears that caffeine does not increase urine production during exercise. The extra adrenaline your body secretes during exercise may block caffeine's effect on the kidneys (3). However, responses to caffeine vary, so you should base your preexercise consumption on how caffeine affects your body.
After exercise, caffeine is a poor choice for fluid replacement. The safest bet is to tank up on noncaffeineated beverages just after activity, and then later, if you so desire, enjoy your favorite caffeinated beverage in moderation.
References 1. Falk B, Burstein R, Rosenbloom J, et al: Effects of caffeine ingestion on body fluid balance and thermoregulation during exercise. Can J Physiol Pharmacol 1990;68(7):889-892
2. Gordon NF, Myburgh JL, Kruger PE, et al: Effects of caffeine ingestion on thermoregulatory and myocardial function during endurance performance. S Afr Med J 1982;62(18):644-647
3. Graham TE, Spriet LL: Caffeine and exercise performance. Sports Science Exchange (Gatorade Sports Science Institute) 1996;9(1)
Me: The exercise physiology book, when (if) I go and read it, is the 2001 ed.
