British Medical Journal casts sceptical eye over sports drinks gospel

[floridatennisdude]

Originally Posted by mikeler

I need something to prevent cramping in the Florida heat. I'm a fan of Gatorade. Was I supposed to read the study to comment in here?

I take a 16oz Gatorade with me to any match. I do one sip every changeover and drink water after that. I rarely get into a battle that 16oz isn't enough sugar and electrolyte to sustain my hydration and energy.

I tried coconut water and felt it did well too. Just can't justify the high price tag when Publix sells 8-packs of Gatorade for 5 bucks and are often buy one-get one free. Coconut water is around 4 bucks for 20oz.

[Limpinhitter]

Originally Posted by Thud and blunder

http://www.bmj.com/content/345/bmj.e4737

Interesting read throughout.

There is an inverse relationship between the reliability of a medical journal article and the financial conflict of interest of the persons involved in the writing and any underlying studies. Scientific fraud in America is epidemic. I know of no basis to distinguish the British in that regard.

Originally Posted by Chas Tennis

Thanks for posting the article.

Originally, there was the famous discovery that British seamen got scurvy because they were lacking fruits. Fruits were later learned to contain Vitamin C. The British navy supplemented fruits into their regular sea-going diet and scurvy was cured.

The supplement industry is escaliting marketing to an ever higher level. I believe, they mostly use the logic - if a chemical, vitamin, mineral, etc can be identified as important to a body process or body structure then supplementing those molecules, atoms, etc is likely to be beneficial. They write very reasonable sounding, detailed scientific model descriptions, down to the cell and molecule level. For example, read the many supplement ads in bodybuilding magazines.

Just because something seems perfectly reasonable does not make it true. But it does not make it untrue either. ? The only way to resolve the issue is with quality, neutral scientific research.

Neutral scientific research should be supported by a neutral government organization (NIH, etc.) or other neutral organization (neutral foundation). Some of it is. But the number of worthwhile research projects exceeds the small funding level available from government funds or other neutral organization. For a particular research project, unfortunately, 100% of the funding might be from self-interested sources with nothing from neutral sources. The government seems to have dropped the ball even on many of the most wide-reaching and serious medical research areas. (Are saturated fats or sugars most damaging for causing heart disease? ) So we get too much knowledge corruption from financially self-interested funded research.

The internet is seeing a lot of cut-and-paste descriptions so that popular unscientific or scientific conclusions appear widely verbatim on many websites. It is often more difficult to find scientific research among the many popular websites quoting the same few phrases. Search certain exact long medical or supplement phrases and you can find them on many websites. Does anyone have some advice on how to search more for neutral information as opposed to the most popular sites or those that influence search results in some financial or manipulative way?

On the other hand, if something seems perfectly true - but might not be true - what should you do? Reject it because most information is corrupted by funding from financially interested organizations?

For sports drinks, I read and it makes sense that the body uses up its glycogen stores in its muscles and liver and may run short during longer athletic activity. Also, I believe that the body sweats water and considerable sodium. I believe that some of the research on these issues is neutral. All things considered, I conclude that its reasonable for me to take in some calories and sodium during a tennis match. The possible value of the other ingredients in sports drinks is totally unknown to me.

A general reference that I use is Advanced Sports Nutrition, D. Bernardot. The reference seems neutral.

I am uncertain about all this. I'm not going to believe that all supplements are worthless or believe that they work as claimed. I can make a decision with considerable uncertainty - that's nearly all decisions.

With considerable doubt about the value, I supplement daily:

1) Glucosamine & chondroitin (2/3 recommended dose)
2) Vitamin C
3) Magnesium (Mg-Chloride not MgO)
4) Multi-Vitamin (5 days a week)
5) Fish Oil (for Omega 3)

Instead of just water I usually drink Powerade or Gatorade for calories and sodium during a tennis match.

Well said. Just be aware that the drug industry has a lot more money to spend than its competition to prove that the competition's products are not effective.

[Dedans Penthouse]

Originally Posted by Bartelby

I think I'll start urinating beside the court at the change of sets from now on.

Squatters rights, I suppose .....

[r2473]

British Medical Journal casts sceptical eye over sports drinks gospel

These Brits win one damn slam in something like 100 years and they are all the sudden experts on everything.

I suppose next we'll be taking advice from the Cubs.

[Big_Dangerous]

Originally Posted by Bowtiesarecool

Interesting fact: The original gatorade developed for UoF worked well at aiding the body in retaining water and giving a short energy boost. However, the formula changed since marketing and is now nothing like the original.

Interesting fact #2: The color of urine is an indicator of where your body is currently getting it's nutrients from. more clear = from food you recently ate, more yellow = you're burning stored body fat. This has been known since the early days of animal experimentation.

I always thought that if it's clear you're hydrated, but if it's more dark then you're dehydrated.

[Frank Silbermann]

Originally Posted by charliefedererer

"Invention of Gatorade

In 1965, Cade was approached by Dewayne Douglas, an assistant coach for the Florida Gators football team, about the extreme dehydration faced by Gator football players ... "It didn't taste like Gatorade," Cade said in a 1988 interview with Florida Trend magazine.[2] In fact, according to Cade, when Gators lineman Larry Gagner first tried it, he spat it out and strongly suggested that the original experimental formula tasted more like bodily waste.[2][12]... To make it more palatable, at the suggestion of Cade's wife, the researchers added lemon juice and cyclamate[14] to the original formula of water, salt, sodium citrate, fructose and monopotassium phosphate.[13]

When I attended U. of F. ( 1975-1978 ) it seemed typical that the football team would start strong early in the season with people naming them as contenders to win in their conference, only to fall back to mediocrity as the season progressed. I speculated that they began the season with a huge advantage over their opponents in heat adaptation, which became decreasingly relevant as the autumn progressed.

In 1978 I attended a dinner sponsored by Tau Beta Pi (an engineering society) at which Dr. Cade was the featured speaker. In his words, the player told him that his drink "tastes like ****!" Dr. Cade continued, "Having never tasted ****, myself, I could not vouch for his claim. Nevertheless, we did work to improve its flavor."

As to the original issue, I recommend drinking water and snacking on any food high in potassium.

[Limpinhitter]

Originally Posted by Frank Silbermann

When I attended U. of F. ( 1975-1978 ) it seemed typical that the football team would start strong early in the season with people naming them as contenders to win in their conference, only to fall back to mediocrity as the season progressed. I speculated that they began the season with a huge advantage over their opponents in heat adaptation, which became decreasingly relevant as the autumn progressed.

In 1978 I attended a dinner sponsored by Tau Beta Pi (an engineering society) at which Dr. Cade was the featured speaker. In his words, the player told him that his drink "tastes like ****!" Dr. Cade continued, "Having never tasted ****, myself, I could not vouch for his claim. Nevertheless, we did work to improve its flavor."

As to the original issue, I recommend drinking water and snacking on any food high in potassium.

Orange juice is high in potassium. But, I think it's a good idea to keep your electrolites in balance. I don't think it's helpful to supplement with only one.

[charliefedererer]

By far, the most important electrolyte to replace during long tennis sessions in the hot sun is sodium - not potassium.


"Sodium’s Role in Hydration and Rehydration for Tennis
The importance of the addition of sodium to fluid consumed during, and especially
after training or competition has been shown to be vital for improved rehydration.
The need for sodium replacement is due in part from sodium’s role as the major ion
in the extracellular fluid, and to replace the obligatory losses in sweat."
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf

"Many athletes do not consume enough sodium in their regular diet to support strenuous physical activity, especially in early stages of training and in hot and/or humid environments.
Having recovery drinks and food that contain sufficient levels of sodium is helpful for a number of purposes:
- Replaces the sodium that is lost in sweat
- Stimulates glucose (energy) absorption by
the muscles
- Increases the athletes drive to drink
- May reduce the symptoms of exertional heat cramps, exertional heat exhaustions and exertional hyponatremia
During multi-day tournaments or practice, it is common for players to experience a subtle but gradual sodium deficit and this can result in heat and hydration related problems (exhaustion, cramping etc) towards the later
rounds of tournament."
- http://assets.usta.com/assets/1/dps/...%20VERSION.pdf


"As sodium has important other benefits such as increasing drive to drink Heat and Hydration Recovery in Tennis USTA Recovery Project 187 and replacing sodium losses that are large in sweat, it appears from the literature that no added benefit is gained by adding potassium to recovery drinks. Potassium rich foods or supplements have not typically been shown to provide additional benefit 75. "
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf



"Cramping
Muscle cramping during and after tennis play is an unwarranted aspect of
high-level competitive tennis. Cramps typically occur with slight muscle
fasciculations 75 or “twitches” that the athlete only notices between points or at the changeover. These subtle signals alert the athlete (and coach) that s/he may only have 20-30 minutes before severe cramps may occur, which would severely hinder the athletes ability to perform at a competitive level. These cramps are often experienced post-play during recovery, between matches and between days during training and competition. With respect to exercise-related muscle cramping, there are typically two forms of cramping that tennis players are most often confronted with:
1) Overworked muscle fibers
2) Muscle cramps related to extensive sweat losses and a sodium deficit,
known as exertional heat cramps 75."
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf

[jrs]

I thought muscle cramps were caused by lack of Potassium. Isn't this the reason for players eating bananas?

[dman72]

I can't drink anything acidic during matches anymore or I have to sprint to the rest room with explosive diarhea.

That rules out pretty much every sports drink as they all have citric acid.

[LuckyR]

Originally Posted by charliefedererer

By far, the most important electrolyte to replace during long tennis sessions in the hot sun is sodium - not potassium.


"Sodium’s Role in Hydration and Rehydration for Tennis
The importance of the addition of sodium to fluid consumed during, and especially
after training or competition has been shown to be vital for improved rehydration.
The need for sodium replacement is due in part from sodium’s role as the major ion
in the extracellular fluid, and to replace the obligatory losses in sweat."
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf

"Many athletes do not consume enough sodium in their regular diet to support strenuous physical activity, especially in early stages of training and in hot and/or humid environments.
Having recovery drinks and food that contain sufficient levels of sodium is helpful for a number of purposes:
- Replaces the sodium that is lost in sweat
- Stimulates glucose (energy) absorption by
the muscles
- Increases the athletes drive to drink
- May reduce the symptoms of exertional heat cramps, exertional heat exhaustions and exertional hyponatremia
During multi-day tournaments or practice, it is common for players to experience a subtle but gradual sodium deficit and this can result in heat and hydration related problems (exhaustion, cramping etc) towards the later
rounds of tournament."
- http://assets.usta.com/assets/1/dps/...%20VERSION.pdf


"As sodium has important other benefits such as increasing drive to drink Heat and Hydration Recovery in Tennis USTA Recovery Project 187 and replacing sodium losses that are large in sweat, it appears from the literature that no added benefit is gained by adding potassium to recovery drinks. Potassium rich foods or supplements have not typically been shown to provide additional benefit 75. "
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf



"Cramping
Muscle cramping during and after tennis play is an unwarranted aspect of
high-level competitive tennis. Cramps typically occur with slight muscle
fasciculations 75 or “twitches” that the athlete only notices between points or at the changeover. These subtle signals alert the athlete (and coach) that s/he may only have 20-30 minutes before severe cramps may occur, which would severely hinder the athletes ability to perform at a competitive level. These cramps are often experienced post-play during recovery, between matches and between days during training and competition. With respect to exercise-related muscle cramping, there are typically two forms of cramping that tennis players are most often confronted with:
1) Overworked muscle fibers
2) Muscle cramps related to extensive sweat losses and a sodium deficit,
known as exertional heat cramps 75."
- http://assets.usta.com/assets/1/dps/...CT%20FINAL.pdf

True Sports drinks contain sodium and severe sodium loss is a cause of muscle cramping and replacing it at that point can relieve the cramping. However from a practical standpoint there are other information to put the above into context:

Muscle cramping is rare in tennis matchplay, regardless of drinks, supplements, weather conditions etc

Only the most severe circumstances lead to cramps, Chang in the French etc.

The main benefit, therefore, of the sodium in sprts drinks is for more rapid rehydration, than warding off cramps.

In the rare case of actual muscle cramps or a legitimate case where the risk of cramps would be high, the levels of sodium in sports drinks is way too low. That's what pickle juice (or salt tabs) is for.

[charliefedererer]

Originally Posted by jrs

I thought muscle cramps were caused by lack of Potassium. Isn't this the reason for players eating bananas?

Old myths die hard.

It used to be thought that low potassium was the major reason for cramping - hence the emphasis on eating bananas that are rich in potassium.

But that is no longer believed.


[Still eating a banana after a match or practice is not a bad idea. It is fairly easy to digest and contains enough carbohydrates to start replacing muscle glycogen (muscle's immediate energy supply) lost during play.
During a match, some can tolerate eating a banana - others develop intestinal cramping.]

[charliefedererer]

Originally Posted by LuckyR

True Sports drinks contain sodium and severe sodium loss is a cause of muscle cramping and replacing it at that point can relieve the cramping. However from a practical standpoint there are other information to put the above into context:

Muscle cramping is rare in tennis matchplay, regardless of drinks, supplements, weather conditions etc

Only the most severe circumstances lead to cramps, Chang in the French etc.

The main benefit, therefore, of the sodium in sprts drinks is for more rapid rehydration, than warding off cramps.

In the rare case of actual muscle cramps or a legitimate case where the risk of cramps would be high, the levels of sodium in sports drinks is way too low. That's what pickle juice (or salt tabs) is for.

I agree with all of the above.

Prevention of muscle cramping is not the primary reason for staying hydrated with sodium containing sport drinks.

Probably the only ones at real risk for low sodium related cramps are those practicing playing day after day in the hot summer, and who have a low sodium diet. (Most Americans probably take in an excess of sodium overall in their diets.) Still, I could see my daughters, who have very low sodium diets, getting into trouble at a tennis camp if they drank only water day after day.

[Frank Silbermann]

Originally Posted by charliefedererer

Probably the only ones at real risk for low sodium related cramps are those practicing playing day after day in the hot summer, and who have a low sodium diet. (Most Americans probably take in an excess of sodium overall in their diets.)

Exactly. When you drink pickle juice or take salt tablets, you're destroying a key health benefit of exercise, namely counteracting your high-blood-pressure-causing excess sodium intake.

By the way, it might make sense for a _British_ medical journal to discourage use drinks to compensate for heavy sweating. Who sweats heavily in their climate?

[Torres]

In the last few weeks I've given up the whole sports drink / high energy drink /caffeine thing. Used to guzzle 3-4 energy drinks before/during a match, some with caffeine eg. Gator, Relentless, Monster, would have a double expresso with a couple of sugars 30 mins before the match to perk me up etc.

It just all played yo-yo with my moods and energy levels. Would end up psyched, aggressive, super tense with too much energy in the first match and then super flat in any match going towards the 2-3 hour point. I just don't believe that any of that stuff or too many stimulants is good for you (well, it wasn't good for me). At times, I was doing a good impression of someone on PEDs.

Now I just try and prepare normally. Have a good nights sleep, healthy meal, a mixed orange cordial during the match and occasionally, a electrolyte drink as I seem to suspectible to muscle cramps in the 2nd match of tourneys for some reason. Could probably achieve the same effect with table salt and water.

[Frank Silbermann]

Originally Posted by dman72

I can't drink anything acidic during matches anymore or I have to sprint to the rest room with explosive diarrhea.

You could try using that to psych out your opponents.

[LuckyR]

Originally Posted by Frank Silbermann

Exactly. When you drink pickle juice or take salt tablets, you're destroying a key health benefit of exercise, namely counteracting your high-blood-pressure-causing excess sodium intake.

By the way, it might make sense for a _British_ medical journal to discourage use drinks to compensate for heavy sweating. Who sweats heavily in their climate?

True, but as I stated in my post, using pickle juice or salt tabs would be a once in a career advantage for players not on the tour, unless you live in the desert and like to play long matches midday. I grew up in SoCal in the Golden Age of American tennis and played midday all the time and have never had muscle cramps from tennis.

[FloridaAG]

Generally water is sufficient. Sometimes the sugar helps. Frankly, I think the flavor is an incentive to drink more so that people do end up more hydrated because they drink more

As I have tried to cut out a lot of artificial stuff lately, I drink only water these days

[newyorkstadium]

I've looked at lucozade sport, gatorade and powerade. They all contain 200mg of salt. Can I replace these with a food that has 200mg of salt, and eat something sugary? I can't stand the taste of sports drinks. A banana barely has any salt, so it doesn't seem that useful. Although Rafa eats bananas in matches??

You lose B vitamins and minerals through sweating. Is it not a good idea to replace them? I used to take a multivitamin to combat this.

[ollinger]

^^ there is no significant loss of B vitmins in sweat. Perhaps you're confusing studies that suggest B vitamins may reduce sweating.