As an addition to the Panorama program on tonight, some folk might fancy a read of the following;
http://www.bmj.com/content/345/bmj.e4797
http://www.bmj.com/content/345/bmj.e4848
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As an addition to the Panorama program on tonight, some folk might fancy a read of the following;
http://www.bmj.com/content/345/bmj.e4797
http://www.bmj.com/content/345/bmj.e4848
Most of those findings don't come as much of a surprise.Quote:
Originally Posted by shaunaneto
But the study sort of overlooks the fact that the simple purpose of sporting carbo drinks, in cycling especially, is just to get some energy on long rides where it's not so easy to eat or carry lots of food.
It's a simple energy in, energy out calculation, with perhaps the added benefit of averting cramp with salts / sugars.
If a proper double-blind test showed that drinks with carbs had no effect on maintaining energy levels, THEN I'd be listening.
For what it is worth this paragraph from the second article certainly goes along with my opinion:
"A more recent systematic review of the effects of exercise induced dehydration on performance in long cycling time trials suggested that drinking according to thirst sensations (as opposed to drinking more or less frequently) was associated with better sports outcomes.(22) One of the studies in the review found that exercise induced dehydration of up to 2.3% of body weight significantly improved performance.(23) The explanation for how exercise induced dehydration might improve performance is straightforward: you carry less weight, and you don’t have to interrupt your exercise."
The "carry less weight" is particularly relevant if you have to carry your own water/drink.
I suspect that once all the evidence is in we will end up with advice along the lines of "drink to thirst, eat to hunger" - with the very important qualification that if you know - because of the length/height gain or the temperature - that you will need to drink/eat during an event then start early with a little and often approach.
Sounds very sensible - except that in my experience being very interested in what I am doing suppresses my awareness of thirst, hunger and needing a loo. I have arrived at the end of LDWA events quite comfortable, only to feel an almost insatiable thirst moments after.Quote:
Originally Posted by Mike T
The "eat when hungry, drink when thirsty" doesn't really work for me, & I imagine it doesn't for a lot of long distance runners. In my personal experience:Quote:
Originally Posted by Alexandra
Eating: I never want to eat anything when I'm running. I'll never get hungry, even when bonking (cycling term: sex while running doesn't appeal either). I have to make myself eat, & I only eat calories as that's all I appear to need. Kendal Mint Cake upsets my stomach least, so that's all I eat. That's a mix of sucrose & glucose, so it gets into & out of my system quickly, so I eat every 45 minutes. The amount is based on what I find I can digest, & Sarah Rowell's advice in her book. 42.5 grams of KMC per 45 mins (3 Romney squares).
Drinking: I can get thirsty when running, but usually I don't, even when getting dehydrated. So I try to make sure I have a drink regularly, every 45-60 mins. Once I start drinking, that's when I find out whether I'm thirsty/dehydrated. I go with what I feel like drinking, & listen to my body - but it only really works when I've started the process by starting to drink. I don't drink more than I feel like drinking, unless it's pretty hot, in which case I might have a little more to allow for the sweating over the next 15-20 minutes.
I've never had any supplements of any kind, or a sports drink. Mind you, I did try Lucozade back in the 60s, when they marketed the same guck as an invalid drink for the elderly. It was horrible then, & I don't imagine that's changed much.
I'm with Splatcher on this. I rarely feel hungry or thirsty even when running for several hours. Despite that I've had one or two bad experiences when I've become pretty dehydrated on a run and definitely feel stronger in the last miles if I do drink & eat. Having said that, I don't eat or drink anything like as much as I see recommended sometimes and nothing "special". Very roughly speaking I only take a drink if I'm planning to run for more than an hour in the tropics (longer in the UK depending on the weather) and drink one or two mouthfuls (100ml?) each hour or so, and it's usually just water or diluted orange juice. I only eat if I'm out for more than about three hours - then it's a banana or handful of raisins, slice of malt loaf.
And I don't think we're unusual in not noticing thirst even when becoming dehydrated. I have lots of friends who do manual work all day under a tropical sun but rarely drink during the day because they say they are not thirsty. They do, however, get frequent headaches caused by dehydration. I know it's dehydration because when they come asking for paracetamol I make them drink a couple of glasses of water and only give the tablets if they still have the headache 20 mins later. They rarely do.
Having said all that, I'm not sure just drinking a lot after the end of a run is necessarily a sign that you were too dehydrated. As Mike's excerpt suggests, being a little dehydrated may actually be helpful but I'm guessing it's a fine line between good dehydration (= less weight) and bad dehydration that impacts your performance negatively. Even though I drink a little while running I'm usually thirsty afterwards (I can easily down a couple of pints of water, milk, tea &/or homemade ORF in the hour or two after a 30 miler). I don't see that as a problem as long as I wasn't becoming wobbly legged or simply finding the going unusually tough in the last miles. Feeling thirsty might be an adequate indicator to avoid this for some people, but not for me.
I would in part agree with some of the above regardind not feeling hunger or thirst.
My reasons may differ, but for me I would be to engrossed in the experience to pay attention. I have lately however been making a conscious effort to ask myself "am I hungry" "am I thirsty" which has not necessarily come naturally. Suffice to say I seem to be running better and with more enjoyment as a result.
Purely from personal experience.
Having now watched the panorama programme, I wasn't too surprised by its findings.
I am constantly amused by the outraged tone of programmes such as this when they describe the action of companies trying to sell things to make more money. I think the questions people should generally ask about the companies are: is it illegal? will it make them more money? if it's "no" and "yes", then of course companies will do it.
My BMJ is becoming better value for money (will never catch up with Fellrunner though :wink:) - 2 major exercise related debates in the last month (there's also been one on exercise and depression).
I don't think it's a good idea to conflate the eating and drinking issues. With eating there is a measurable loss of performance if hypoglycaemia occurs after depletion of glycogen stores and eating some calories thereafter is essential to preserve activity above what fat burning can support. Even in those who have great natural and trained fat burning capability and running economy there will be a benefit from carb calories and ingestion of carbs is worthwhile in the absence of hunger (and often presence of nausea). With drinking there is no good evidence that dehydration impairs performance over the distances and times studied and therefore no reason to advocate drinking in the absence of thirst. There have been deaths in marathons due to over zealous rehydration causing hyponatraemia. Much is also said of the need for electrolyte intake which again lacks any proper evidence and this is also often tied in with prevention of cramp whilst the evidence suggests cramp has nowt to do with electrolyte status. As for f'in' beetroot don't even go there :rolleyes:
As far as sports drinks go my 2p is (in agreement with points others have made) firstly that I find it easier, when driven to drink by thirst during a run, to get something flavoured down my neck than plain water - generally Nuun nowadays as most energy drinks are so sweet as to be off-putting and I can dip stream water and add tabs on the run. Maybe I've still got some illogical attachment to the electrolyte stuff too. Secondly, if you acknowledge the need to get calories in then many will find ingesting them by drink, which is going down for hydration anyway, is the best tolerated and easiest way to do it. So to my mind they're useful and not a complete con but hugely and knowingly oversold by the manufacturers. It is also annoying that so much bad science has been wilfully created to pollute the environment and a shame that all those funds couldn't have been channeled in to some decent research.
I've made a mental note to go back and read the evidence for mixing carb and protein rather then just carb in the endurance setting - I was reasonably convinced by the limited published evidence but can't really remember the ins and outs of it or the level of evidence. There are several products using this mix now -eg a SIS drink - and I maybe convinced to give these a go versus Nuun and food
At the end of the day there's a lot to be said for the placebo effect - if you feel it's doing you good in a sporting context it probably is, mentally at least - so long as the placebo is harmless and not bankrupting
cheers, P
Intriguing post, and one that appears to be based on whimsy rather than science. From Wikipedia...Quote:
Originally Posted by Alexander
Based on Prof Barkoukis' comment, i'd go a long way to avoid drinking one of those prior to a run; and i can't see how an energy drink containing zero carbs could provide any energy whatsoever. Perhaps the Dublin based personal trainer your signature is advertising could shed some light on things?Quote:
Originally Posted by Wikipedia
Interesting how in the Panorama programme they showed Tim Noakes laughing at length at the idea of zero calorie electrolyte replacement drinks, whereas in The Lore of Running (by Noakes) there is a long detailed section on the importance of replacing sodium lost through sweating (4th edition, pp 213-217).
Summary: sodium determines the level of water in extra-cellular fluid; if you lose a significant amount of sodium through sweating and then just drink plain water, excess water is excreted to maintain proper osmolality - ergo, you still end up dehydrated. Therefore electrolyte supplements (eg Nuun) have a role to play.
I think the programme both misrepresented/oversimplified the scientific view and - perhaps more importantly - didn't really give much weight to people's actual experiences beyond setting up a few vox pops coming out of a gym to look like gullible stooges. They did this so they could present a sensationalist picture of credulous consumer-drones being duped by big corporations (again!). Muddled and without much room for nuance.
I think Noakes laughed because the discussion at the the time had mainly been about energy drinks. The electrolyte concentrations in most sports drinks are far too low to differentiate them from non electrolyte containing drinks in any way other than taste - in particular they do not reduce the risk of hyponatremia.Quote:
Originally Posted by eardstapa
Under conditions of stress - marathon running/fell running/triathlons/multiday events - the body ignores osmolarity and retains water so that if excess water is taken in hyponatremia results. Supplements such as Nuun do have a role to play, though "most people" who become hyponatremic are mainly or purely water overloaded, rather than salt depleted. "Most people" have been poorly advised about fluid intake, and are not used to the long days out in the hills that most fell runners cope with easily.
Such programs are by definition simplistic, and have to be a bit sensationalist to get an audience - it was still interesting to see that others have not been able to find a scientific justification for most of these heavily marketed products - many will have held this view for some time, but of course there is a tendency to look for that which confirms an already held point of view, and ignore that which doesn't.
Good post. That's exactly what I was thinking. :)Quote:
Originally Posted by Mike T
Quite true. I think I fit into a somewhat broad and indeterminate margin between "most people" and the chosen few proper hard men (:wink:) and am probably too willing to try anything that might make me feel a bit less like crap than I do after a few hours. Thanks for explaining that bit about the body ignoring osmolarity under stress; very interesting (I shall remind my own body which continues to sweat profusely and saltily long after I wish it would stop!:rolleyes:)Quote:
Originally Posted by Mike T
Sports drinks may be useful for the moment but using them on a regular basis is not a good choice. Energy drinks contain high sugar and caffeine value and may be bad for your fitness. But for heavy runners the situation is little bit different because they need some quick energy after running...
For those of you that are interested in the up to date knowledge on hydration, sports drinks etc, noakes has a new book out on it.
It's got pretty much all the recent studies and reviewed papers on hydration, and a fair amount of discussion as well. Not got hold of a copy yet, but its been highly recommended to me.
It's called waterlogged : the serious problem of over hydration in endurance sports
http://www.amazon.co.uk/Waterlogged-...2755475&sr=1-1