(Isotonic) Electrolyte Sports Drinks

ddraver

Hi All

I'm not trying to start one of the inevitable willy waving competitions that usually accompany these discussions but does anyone have a decent link to some proper science on whether or not isotonic sports drinks (i.e the SIS or high5 electrolite tablets) - ones that are NOT Energy Drinks - have any measurable effect, and over what sort or time/effort?

Just interested really...

David

meanredspider

I'll have a look when I'm back in Scotland. I have a motorsport fitness book written by someone who trains F1 drivers and he links to some science as I remember. Interesting question - I find they seem to help stave off cramp but, as has been pointed out on another thread, that might be a placebo effect (especially as cramp is poorly understood by science).

Mikey23

im of the waste of money why not use squash school of thought but will await some learned paper proving me wrong!

FatTed

Mostly complete Bo;;ocks
Drink when your thirsty
drink water
Eating is another matter

charlie_potatoes

And so it begins.....

ddraver

Hmmm, I ask becasue i was talking with a very good level racer who said that the point of electrolyte drinks is that they increase the amount of water that is absorbed. So if you re drinking plain water and excercising hard then you may still become dehydrated, therefore affecting performance - or to put it another way, you need to drink less water with electrolytes than pure water.

Now i'm a geologist, not a biochemist but something about that sent up a red flag for me... How would having slightly salty water encourage water molecules to move into the bloodstream in the gut, which is what we re talking about...

I suspect that part of the problem is that studies on gym bunnies who only do 45-60 min workouts would show that they re pretty much useless, just becasue there is no time for any water drunk to make any real difference. But in a 3-4+ hour ride on a warm day then it might start to make a difference. However, like a lot of studies on cycling, i suspect that it's very hard to design a study that removes all the other variables that could affect "performance"

Edit - What I mean to say is how would having slightly salty water encourage water molecules to move into the bloodstream in the gut, BETTER THAN Fresh water..?

ugo.santalucia

ddraver wrote:

Edit - What I mean to say is how would having slightly salty water encourage water molecules to move into the bloodstream in the gut, BETTER THAN Fresh water..?

... and going against osmosis...

meanredspider

Yup - I think the salts are absorbed too so nothing to do with osmosis

ddraver

So...Salts absorbed first thereby increasing the salinity in the bloodstream therefore encouraging water to diffuse into the bloodstream?!?

Must be something to do with partially permeable membranes and all that....

drlodge

Interesting read here http://triathlete-europe.competitor.com ... orts-drink

ddraver

Yep - so the crucial bit is this...

Most sports drinks on the market are what sports scientists call isotonic, which means they contain a carbohydrate solution that is at 6-8% concentration. These drinks are in the middle of the spectrum in terms of absorption rate, with water being the most readily absorbed (hypotonic) and something like fruit juice, being greater than 8% sugar concentration (hypertonic) and therefore the least absorbable. Because the sugar concentration of most sports drinks is higher than that of most body fluids, they are not readily absorbed into the blood stream and are thus not optimal for the purpose of hydration.
[...]

By drinking water alone, diluting your sports drink, or using electrolyte substitutes, you provide your body with the best combination of electrolyte replacement and immediate absorption. Likewise, electrolytes, especially sodium and potassium, reduce urine output, speed the rate at which fluids empty the stomach, promote absorption from the small intestine, and encourage fluid retention.

So the question is why does having electrolytes in the drink encourage water absorbtion (but not sugars)?

Diamant49

I cannot remember the exact details, its to do with sodium concentration in particular (sodium pump mechanism?), in part its osmosis, but some transport is against the osmotic gradient. Sodium is also involved in glucose transport from the gut.

Pure water, in theory, dilutes the gut contents too much, hindering sugar absorption - and also passes through too quickly, making you pee too much. I certainly drink less on the bike than recommended, but more than I used to many years ago - one thing I notice is that I don't need to pee much, if at all if there are some electrolytes in the fluid. You don't need to go as much when exercising anyway, but its still more often with pure water.

A quick look and this link explains quite a bit - so there is science behind it, but maybe the claims are still over hyped?

http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/absorb_water.html

paulleary

when you sweat you not only lose fluid , but sugar and salts/minerals as well. if taken to the extreme it can be very dangerous. when we treat people for dehydration through diarrhoea and vomiting we use rehydration salts to help replace the sugars but especially the salts lost eg Dioralyte . A long bike ride will certainly make you sweat a lot if your anything like me . you could make your own with a teaspoon or two of sugar and pinch of salt in your bottle , but that wont give any potassium or magnesium . Another benefit of the tablets is they taste nice , thereby encouraging you to drink more which is a good thing . If you dont need a comfort break every hour or two your not drinking enough and are almost certainly dehydrated to one degree or another . but as in everything each to his own . I usually use the hifive tabs as i like the tatse .

shockedsoshocked

The Gatorade Sports Institute and Professor Jeukendrup who works with them are a good place to start.

http://www.gssiweb.org/publications/all

Gatorade appear to actually be interested in Sports Science unlike a few of the the everyday brands.

Tom Dean

Trevbait

ddraver

I know but thankfully he's no more so we can have an adult discussion...

Paul can you think back to Med School and tell us how the salts help?

hypster

ShockedSoShocked wrote:

The Gatorade Sports Institute and Professor Jeukendrup who works with them are a good place to start.

http://www.gssiweb.org/publications/all

Gatorade appear to actually be interested in Sports Science unlike a few of the the everyday brands.

Much of the research that has been done showing the benefits of sports drinks in the past 30-40 years has been funded by companies like Gatorade. Gatorade are only interested in selling Gatorade. To think anything else is pure delusion.

ddraver

Anything useful to add hypster?

meanredspider

Looked this up in my book as promised. The book, BTW, is the Motorsport Fitness Manual by Dr RS Jutley and has a forward by F1's legendary Prof Sid Watkins

For starters, I think maybe the title is wrong. "Isotonic" is the same electrolyte concentration as the body and tends to refer to "energy" drinks with a carb level of 6-8% - these are absorbed at the same rate as plain water. Hypotonic drinks have a lower concentration (Zero, Nuun and the like) and pass through the stomach quicker to the small intestine and are absorbed quicker and are better for hydration that plain water. They also don't promote urination as much as plain water (due to the electrolytes) and minimise the risk of hyponatraemia (over hydration) which is present with plain water.

The functions of the electrolytes are:
- many are essential minerals
- they control osmosis of water between body compartments
- They help maintain the acid/alkaline balance for normal cell activities.

For me, tabs like Zero certainly help with cramp and, at 50p a pop, even if they just taste good, I'll take the risk.

drlodge

meanredspider wrote:

For me, tabs like Zero certainly help with cramp and, at 50p a pop, even if they just taste good, I'll take the risk.

The High5 Isotonic I use is probably about that price - £18 for a 2kg tub, so it costs very little and provides some energy and electrolytes in the mix. Seems cheap enough even if its benefits are dubious, its at least as good as water

hypster

ddraver wrote:

Anything useful to add hypster?

Google "Waterlogged" by Dr Tim Noakes

meanredspider

hypster wrote:

ddraver wrote:

Anything useful to add hypster?

Google "Waterlogged" by Dr Tim Noakes

Which, honestly, has nothing to add to this discussion. It's out of date, not related to cycling but distance running and relates to plain water. In fact, from what I have understood, isotonic and hypotonic drinks help protect from over-hydration.

bockers

Over-hydration, I thought, is not so much a problem of too much water but more a problem of that excess flushing out too much of the essential electrolytes and minerals in the blood. This assumes an empty stomach and intestine too as otherwise the water just mixes with the recent food and takes on salt, sugars etc. Over-hydration requires a lot of other actions to take place along with the excess water. This combination is pretty rare in cyclists, and nigh on impossible for the mamils amongst us

ddraver

Thanks msr

Response from my Biochem Friend

I’m not sure – the only explanation I can think of is that the salts in the electrolyte drink are absorbed via salt channels (to replace the salts lost in sweating) – then its osmosis I guess once the salts have been absorbed the water follows :-S

So I guess the more you sweat the more effective the electrolyte drinks are???

Seems to match the consensus...

meanredspider

bockers wrote:

Over-hydration requires a lot of other actions to take place along with the excess water. This combination is pretty rare in cyclists, and nigh on impossible for the mamils amongst us

Yes - even in the esteemed Dr Noakes reckons the ideal volume is 400-800ml per hour. I think your average amateur cyclist is going to struggle to take more than that onboard (who stops every hour to refill their bidons?). The problem is distance running is that there are regular water stations with ample water. And you're absolutely right - the problem with over-hydration is that the bodies functions start to break down because of the lack of electrolytes.

It's a red herring other than to support the addition of electrolytes to your drinks.

hypster

meanredspider wrote:

hypster wrote:

ddraver wrote:

Anything useful to add hypster?

Google "Waterlogged" by Dr Tim Noakes

Which, honestly, has nothing to add to this discussion. It's out of date, not related to cycling but distance running and relates to plain water. In fact, from what I have understood, isotonic and hypotonic drinks help protect from over-hydration.

That's only partly true and the book is not just about over-hydration but carries a lot of information about absorption in the gut of electrolytes and carbohydrate. I'm also confident that he knows a lot more about the physiological make-up of human beings as it relates to the performance of endurance athletes than a bunch amateur cyclists speculating about it on an internet forum (me included).

meanredspider

hypster wrote:

meanredspider wrote:

hypster wrote:

ddraver wrote:

Anything useful to add hypster?

Google "Waterlogged" by Dr Tim Noakes

Which, honestly, has nothing to add to this discussion. It's out of date, not related to cycling but distance running and relates to plain water. In fact, from what I have understood, isotonic and hypotonic drinks help protect from over-hydration.

That's only partly true and the book is not just about over-hydration but carries a lot of information about absorption in the gut of electrolytes and carbohydrate. I'm also confident that he knows a lot more about the physiological make-up of human beings as it relates to the performance of endurance athletes than a bunch amateur cyclists speculating about it on an internet forum (me included).

And he's also trying to sell a book....

hypster

meanredspider wrote:

And he's also trying to sell a book....

That may well be true meanredspider but as an argument to ignore possibly useful information it's totally flawed. In which case no-one would buy any books because the information contained therein is possibly misleading and just designed to sell the book. We've had this discussion before and I hesitated to post the suggestion to Tim Noakes' book but it was germane to the discussion despite your assertions to to contrary, so I posted anyway and let people make up their own minds.

There are plenty of detailed references to Tim Noakes' work on the internet as well including YouTube videos so you don't necessarily have to buy the book to get a flavour for his research and conclusions. Your dismissing the ideas out of hand as relating only to endurance runners doesn't necessarily make them any less applicable to endurance cyclists. Maybe you should write a book of your own and see how far you get with it.

FatTed

hypster wrote:

ShockedSoShocked wrote:

The Gatorade Sports Institute and Professor Jeukendrup who works with them are a good place to start.

http://www.gssiweb.org/publications/all

Gatorade appear to actually be interested in Sports Science unlike a few of the the everyday brands.

Much of the research that has been done showing the benefits of sports drinks in the past 30-40 years has been funded by companies like Gatorade. Gatorade are only interested in selling Gatorade. To think anything else is pure delusion.

+1
Drink when your thirsty and drink water.
Eating is a separate issue
http://www.bmj.com/content/345/bmj.e473 ... lhsQ%3D%3D

meanredspider

If you remember the last time we discussed this, I posted information that indicated in studies there were NO examples of over-hydration in endurance cycling. Above I've suggested why this might be. As it happens I've just watched the BBC video on marathon preparation and the prof on there warns of over-hydration and suggests it easy to do there because so many people are just hanging around at the start of the event with nothing better to do than drink.

For sure, I expect there's information on electrolytes in his work. Rather than have us blindly stumble around Google looking for the stuff that might be relevant, it would have been more helpful to either point us directly to it or, better still, quote or précis it here.

hypster

meanredspider wrote:

If you remember the last time we discussed this, I posted information that indicated in studies there were NO examples of over-hydration in endurance cycling. Above I've suggested why this might be. As it happens I've just watched the BBC video on marathon preparation and the prof on there warns of over-hydration and suggests it easy to do there because so many people are just hanging around at the start of the event with nothing better to do than drink.

For sure, I expect there's information on electrolytes in his work. Rather than have us blindly stumble around Google looking for the stuff that might be relevant, it would have been more helpful to either point us directly to it or, better still, quote or précis it here.

I'm sure I pretty much agree with you in principle but we are not just talking about over-hydration here. There seems to be so little useful research being done related purely to endurance cycling, especially for amateurs that we have to glean what we can from what is out there. When it comes to stuff like Tim Noakes' work I am no expert and have only stumbled around the internet myself cobbling together bits of information which I think is relevant to what I am doing.

As far as I can see even experts are divided on this stuff because so little meaningful research has been done which is why there is so much resistance to ideas like Tim Noakes' I think. Indeed one of the problems he highlights (for marathon runners admittedly) is the ignorance by medical staff who assume that runners collapsing at the end of events must be dehydrated and pumping even more fluid into them exacerbating the problem to the point of contributing to the patients death. Again, I admit that that is a problem of over-hydration which probably isn't a problem for us but it is a indication of the ignorance which prevails even amongst medical professionals.

The associated issue which was the original subject of this thread is one of the use of electrolytes (and maybe carbohydrates) in energy drinks. I don't know the answer to that one and as you said earlier, research is unsure as to whether it helps prevent cramp etc. You think it does and I am prepared to accept that it does but the jury is still out on that one either way.

As far as posting links to Tim Noakes' work I would be quite happy to but I don't really think it's helpful to post extracts of it or even precis it because I might put some spin on it which isn't correct. I would much rather people do their own research and make their own minds. As you say, it predominantly relates to ultra-marathon runners but is still relevant to the endurance cycling that we do but maybe with a bit of interpretation.

http://www.irunfar.com/2012/07/waterlog ... -book.html
http://www.youtube.com/watch?v=8dFlV-Rn1yw

Hammer Nutrition also quote Tim Noakes' work in their documentation so they must think it has some validity and relevance to endurance cyclists as well.

http://www.hammernutrition.com/knowledg ... ge-section

Please don't dismiss them as just trying to sell you a product as well (they are!). Read through the marketing BS and assimilate the ideas behind what they are telling you. I don't use any of their products by the way and never have. I just use a much cheaper version of my own concoction.