Hydration Blog

Sodium pre-loading

Fri, 15 Aug 2022 15:44:00 GMT

An interesting study into pre-loading with sodium rich drinks before exercise….

Sugihara and colleagues have just published online in the European Journal of Applied Physiology (link to paper here) their 8-subject study that looked into the effect of ramping up the sodium content of a drink on hydration status. The hypothesis being that if the athlete is hyperhydrated with a higher sodium drink then performance increases. Or at least performance degradation is slowed. The drinks used were of fairly high sodium content (1380mg/L, 2760mg/L and 4140mg/L) when you consider sea water is around 10,000mg/L, Gatorade is 450mg/L while Powerade stands at 225mg/L.

The results supports previous work that showed the higher sodium drinks induced hyperhydration with an increase in plasma volume and net water gain. But the higher levels of sodium in the drinks also induced diarrhoea and gut upset. Not pleasant if you're competing and in fact defeats the purpose of taking the drinks in the first place.

What is interesting from our point of view was to see was that the 1380mg/L drink, at 90 min after consumption increased plasma volume compared to water and that the net water gain was maintained at 120 - 150 min after ingestion, without causing excessive gut issues. So overall it suggests that there is no great need to take sodium in really high quantities, and that using H2Pro Hydrate 1500 (1500mg sodium per litre) as many athletes do to enhance pre-event hydration, should be sufficient.

Individualisation - the key to optimal hydration?

Fri, 28 Jun 2022 10:46:00 GMT

Individualisation - the key to optimal hydration?

Having come across 2 interesting articles in the mainstream Running and Triathlon press recently we thought it was a good time to put up a post about just why individualisation is so important when looking at hydration.

First up; a great article by TJ Murphy on Triathlete-Europe entitled 'Does Dehydration Improve Performance?'

http://triathlete-europe.competitor.com/2013/06/21/does-dehydration-improve-performance

In the article TJ highlights the case of legendary triathlete Scott Molina who famously struggled at the Hawaii Ironman as he battled dehydration, hyponatraemia and pacing issues for years that preventing him from winning the event, despite being amongst the favourites to do so.

He also explores the conclusions in Dr Tim Noakes' 2012 book, 'Waterlogged' that suggest most athletes tend to over, rather than under consume fluids during exercise and that this is largely as a result of the marketing hype created by drinks companies keen to drive up sales of their products.

We think that one of the best things about this article is the fact that it does acknowledge that whilst Dr Noakes is likely to be very correct in his assertions that a lot of athletes do over drink (thanks to the efforts of the industry to encourage this habit), Murphy also points out that for an individual like Molina who reportedly had a sweat rate of up to 3 litres per hour(!) working out what you need in your own circumstances is the key to optimising your own performance.

As it turned out in the end Molina did some great homework to understand his own physiology better and came up with an individualised approach to fluid intake and pacing that eventually allowed him to go on and win the Ironman in 1988.

The article closes with a fantastic quote suggesting that "Everyone keeps searching for some perfect answer for matching hydration and performance, but perhaps Mucky Sludge [Scott Molina's nickname] blazed the path for us long ago. We each have to figure this out for ourselves."

The other article is on pg 27 of the latest UK Runners World magazine (August 2013) and highlights the case of Ultra marathon runner Sophie Power who drank herself into a dangerously hyponatraemic state in a multi day race. This was despite that fact that she was taking 'electrolyte' tablets that turned out to actually have a very low sodium content. She was lucky to survive the incident due to the quick thinking of the event medical team but others have tragically lost their lives in similar circumstances.

So what does all this show?

Well, we think that understanding your own hydration needs based on factors including your own sweat rate, sweat sodium concentration, the length, intensity and environmental conditions of your training and races is key to determining what will best work for you. With some intelligent preparation, research and organised trial and error you can find a hydration and electrolyte strategy that will help you to perform at your best and stay healthy.

In essence it's exactly why we are making sweat testing more widely available to athletes and producing the only multi-strength range of electrolyte drinks in the world - H2Pro Hydrate - so people can tailor their replacement strategies more closely to their own needs.

Cramping and Electrolyte Loss - what is the link?

Mon, 18 Mar 2023 12:10:00 GMT

We get asked all of the time about whether electrolyte replacement (particularly sodium) can help with athletes who get cramp. It is always frustratingly hard to explain why sometimes electrolyte supplementation can be like a complete miracle cure for cramps in certain people, however for others it does not help much at all....

We believe it is likely to be because although electrolytes are implicated in some instances of muscle cramping, many other factors such as fitness level, fatigue and the type of movement patterns being undertaken can also be the cause.

In terms of our own experience in the field with 1000's of athletes we tend to find that a more tailored approach to sodium replacement (with drinks closely matching sweat composition, taken to thirst) reduces incidences of cramping in those who tend to suffer cramping late on in endurance events or in competitive games/matches/tournaments after prolonged periods of sweating. This effect tends to be magnified in hot weather or when intensity is very high, and is more pronounced in athletes with high sweat sodium concentrations and/or very high sweat rates. We have also noted some anecdotal experiences of athletes who used to suffer with cramps when taking in high volumes of plain water or low sodium fluids (because they were scared of becoming dehydrated) - and these athletes often see a reduction in cramping when they have either reduced total fluid intake to more normal levels or taken in additional electrolytes with fluids (or a combination of the two).

Results with athletes who cramp at seemingly random times tend to be less positive (when using sodium supplements alone) - however programmes of targeted stretching, sports massage, more progressive training overload and general dietary improvement can be helpful in reducing the likelihood of cramping occurring in these individuals.

Because of all this we thought we'd share a review article that does a very good job of explaining the possible links between cramping/fatigue and sodium depletion - and it is well worth a read if you are interested in finding out more about the topic as a whole.

The reference is:

Bergeron, Michael F. “Muscle Cramps during Exercise V Is It Fatigue or Electrolyte Deficit?” Current Sports Medicine Reports: Supplement-Sodium Balance and Exercise 7.4 (2008)

And the full article can be read of downloaded from this link

A genetic reason for why some people lose more salt in their sweat than others?

Wed, 21 Nov 2022 11:38:00 GMT

A genetic reason for why some people lose more salt in their sweat than others?

We recently came across an interesting study from the USA which offers a very good explanation of why some people are high salt sweaters and others low or normal. This group in question biopsied the skin of 3 groups of people - those with cystic fibrosis (known to have high levels of sodium and chloride in their sweat), those with high sweat sodium levels but not CF sufferers and those with normal sweat sodium levels. Those with CF and high salt sweaters had a lower abundance of a protein called cystic fibrosis transmembrane conductance regulator (CFTR). This protein is responsible for absorption of chloride and sodium in the sweat gland so a lower level means less is absorbed back into the blood and more is excreted out in sweat.

Ref:

Brown MB. Low abundance of sweat duct Cl⁻ channel CFTR in both healthy and cystic fibrosis athletes with exceptionally salty sweat during exercise. Am J Physiol Regul Integr Comp Physiol. 2011; 300: R605–R615

More Evidence For Drinking To Thirst, as well as consuming electrolytes, especially if you lose a lot of salt in your sweat....

Wed, 31 Oct 2022 14:51:00 GMT

More Evidence For Drinking To Thirst, as well as consuming electrolytes, especially if you lose a lot of salt in your sweat....

Reading Tim Noakes' book "Waterlogged" does make you think hard about whether one should simply respond to their thirst stimulus rather than try to replace lost volume. I generally do agree with this idea (it seems quite a lot of athletes make the mistake of drinking too much pre, during and post exercise) although do disagree with his observation that sweat sodium levels do not very dramatically between humans. There is in fact plenty of evidence that there is a massive variation (infact in a later blog I will describe the genetic basis for the variation that results in lower number abundance of a protein called CFTR).
Just recently while trawling the sea of evidence related to this topic I came across a study done in Georgia, USA in 2011. The group looked at thirst responses in cystic fibrosis (CF) suffers, non-CF active people with high sweat sodium levels ('salty sweaters') and controls with average sweat sodium levels. After forcefully dehydrating them by 3% of their body weight in a heat chamber they showed that thirst responses were equal across all groups. They concluded that the thirst mechanism is maintained despite the large variation of sweat sodium losses, blood osmolality and plasma volume between the groups. They concluded, relevant to our fundamental principle of sweat sodium replacement, that "....sweat Na⁺ losses observed in SS (non CF but high salt sweaters) and CF provide empirical support for models and recommendations for consuming electrolytes during prolonged exercise to guard against the potential for hyponatremia in salty sweaters..."

So in agreement with Noakes, drink to thirst. No matter what your sweat sodium losses your thirst appetite will be preserved. But drink what you lose.

Dr Raj Jutley.

Ref:
Brown MB et al. High-sweat Na⁺ in cystic fibrosis and healthy individuals does not diminish thirst during exercise in the heat. Am J Physiol Regul Integr Comp Physiol. 2011; 301: R1177–R1185

Placebo effect?

Thu, 26 Jul 2022 13:06:00 GMT

We received the email below from a customer a few days ago and thought it would be a good idea to share his question our response and his subsequent reply online - especially given the amount of interest there has been in sports drinks since the BBC Panorama documentary highlighting the British Medical Journal's latest thinking on sports drinks was aired on July 18th....

We'll follow on with a more in-depth comment on the BMJ article and also on Dr Tim Noakes' book 'Waterlogged' soon.

Question:

Hi Guys,

I would be interested in your thoughts on the lack of need for hydration products as currently proposed by Tim Noakes. He says there is no need for anything like this. He also says that sweat with high levels of sodium are just because of high intakes of sodium and to cut this out also means that the sodium levels in sweat will in turn drop. I went to the talk at all 3 motion and have been using your products and have got on fine so far but I’m wondering if this is placebo or not?

Our response:

Thanks for your email.

It's a very interesting question, one that we're being asked more and more here is our take on it:

Firstly whilst we have a huge amount of respect for Tim Noakes and his work he has a record of being quite provocative in his approach to certain topics. He likes to challenge exists dogmas and this is both healthy and necessary in science. However, sometimes he adopts quite an extreme position (in this case that sports drinks are completely unnecessary and that the companies that sell them are conning us) partly, I think, to get people to sit up and take notice and this certainly works!

For starters we do agree with his point that listening to thirst is a good idea. Too many people do force fluid down too frequently and suffer as a result and in our advice to athletes we take a similar position.

However, one of the main points that we'd disagree with in his new book is in the way it dismisses that there is a large variation in sweat sodium losses; saying that they are relatively similar between people and mainly driven by dietary sodium intake. Our own data (which is probably one of the most comprehensive sets available) shows a much wider variance in sweat sodium values (approximately 19mmol/l to 84mmol/l) in well trained athletes than he quotes in the book (around 20-40mmol).

It's certainly possible that at the extremes when people are taking in huge volumes of sodium, or virtually none at all, the body could respond by losing more or less in sweat but the fact remains that the main mechanism for regulation of sodium is in the kidneys absorbing or excreting more in urine. From the large numbers of people we have tested (some of whom in professional rugby and football teams all eat similarly controlled diets to one another yet still show this wide variation in sweat sodium levels) it is clear there must be something other than just sodium intake dictating sodium loss in sweat and it would appear that this is genetics.

On a personal level as I explained in the talk at All3Motion one of the biggest drivers for me in getting my own sweat tested many years ago and looking into this topic further was that I had found by trial and error that by taking in lots of sodium in races I a) stopped cramping (as I had done a lot beforehand) and b) generally my performances improved dramatically. The consistent way in which this happened (and from listening to the experiences of other athletes we've tested and talked to over the years) leads us to strongly believe it cannot just be put down to a placebo effect.

Also, although Dr Noakes is very sure in his opinion that sodium loss has absolutely nothing to do with cramping a lot of anecdotal evidence would suggest otherwise. For sure we don't believe it to be the only factor involved but the amount of athletes who have stopped cramping when we've upped their sodium intake in endurance events is significant. Again our own data from sweat tests and questionnaires shows a statistically significant correlation between athletes who report that they cramp regularly and the fact they tend to have higher sweat sodium levels. This may not offer definitive 'proof' of a link but it ties up with enough anecdotal experience to be taken seriously.

As with a lot of topics in science and sports performance if you search hard enough you can definitely come up with a lot of evidence to prove and disprove most theories. Do we agree with Dr Noakes that many of the big sports drink companies have 'hyped' the efficacy of their products in order to sell more of them? Absolutely. Do we think that there is no benefit to be derived from intelligent use of certain supplements (such as sodium) to prevent performance dropping off as the body gets depleted during extended periods of exercise? No.

Kind regards

Andy

Subsequent reply:

Thanks for the very detailed reply. It’s refreshing to get that sort of detail.

For my experience with your products I have not suffered any cramps this year since I started taking them.

This year I have run Ultras, 40, 50 and 100 miler and all using your 1000mg product. I found they helped with hydration and absorbtion of food which is something that I think gets little coverage and is vital.

In the Cardiff 50 this year at mile 46, I came across a guy who could not stand, let alone walk due to massive cramping. He was actually trying to call his wife as he was going to withdraw as he was in so much pain.

Luckily for him I had your tablets freshly prepared from the last aid station and I made sure he drank the majority of my bottle, I left him alone to deal with his pain and carried on hoping that he may be able to stumble the remaining 4 miles.

Well I'll be! He came flying past me about 10 minutes later saying I had saved him and the drink was an elixir of life! This really pleased me but because I was now being beaten by Lazarus I had to step up my game as there was no way I was going to be beaten by someone who was practically DNFing 10 minutes earlier. Needless to say we both finished in just over 8 hours and I did beat him and came 28^th. He was all over me with emotion at the finish line and kept telling everyone he could how I had saved him. In fact it was your product that saved him I just happened to have some ready and was willing to share.

I used it on the 100 I finished 2 weeks ago and has no issues at all although my ankle did swell up like crazy due to terrain etc but I finished in 24.08 and beat myself up for ages for not going under 24 hours but I knocked 2 hours 27 off my 85 mile time from 2 years ago and ran 15 miles further and on harder terrain and elevation so that cant be bad! I have also got my mate Max Dillon who came 3^rd at Cardiff on to the product and he loves it too and has had no issues.

Regards,

Creative uses of H2Pro Hydrate.....Nutrichef add them to a smoothie...

Fri, 18 May 2022 16:57:00 GMT

We thought we'd share this one.

We hear of people using H2Pro Hydrate tablets in some creative ways from time to time; adding them to carbohydrate drinks to boost the sodium content or mixing them in 50/50 with flat coke and water to create a very effective caffeinated, carb drink for racing. But this is definitely the most sophisticated use we've come across so far.

What's more it's from a very well respected source in the world of nutrition; Barbara Cox, CEO of Nutrichef (who incidentally you can follow on twitter @NutriBarbara), and she's been adding it to her smoothies....Thanks for the heads up on this Barbara....

H2Pro Smoothies:

Dissolve 1 table in 500mls water

Add 1 banana

Add handful of strawberries and blueberries

1 tbsp Chlorella (sea algae for protein)

1 shot wheatgrass juice (I use live frozen wheatgrass shots)

Whizz all together in the blend and voila….gorgeous!

It sounds like a really good post exercise recovery drink (plenty of carbs from the fruit, fluids and electrolytes from the H2Pro Hydrate and water and some protein) We're going give it a try once we figure out where to get some Chlorella from!

H2Pro Hydrate at the Patrouille Des Glaciers

Thu, 10 May 2022 08:48:00 GMT

The Patrouille Des Glaciers (PDG) is one of the worlds toughest ski mountaineering races. Held every 2 years in the Alps near Zermatt, Switzerland it is an event with military origins and in 2012 a group of British soldiers headed out to take on the challenge - using H2Pro Hydrate to keep their fluids and electrolytes topped up in a very harsh, unforgiving environment. This is what they had to say about their experience:

"Despite having limited time to prepare we used H2Pro during the flight to Switzerland 48hrs prior to the race which undoubtably helped with our basic hydration. During our training day before the race we tested the race concentration to confirm suitability. Not only did the product keep us hydrated during a long and arduous day but I'm convinced it helped us adjust to the altitude and acclimatise quicker. Although the race was stopped due to avalanches I am sure H2Pro mitigated our lack of environmental training and acclimatisation."

Hydration at high altitude can be an issue due to the dryness of the air and sweat losses whilst ski mountaineering can be very high as it requires a lot of clothing to be worn to protect against the elements yet work rates are very high. Having H2Pro Hydrate in the water they were carrying also helped to stop it freezing up in sub zero temperatures.

We will be supporting the British team in 2 years time when they will get a second chance to take on the PDG - hopefully this time without the avalanche risk that cut this years race short.

Lee Shannahan with his H2Pro Hydrate and the Matterhorn in the background:

The Ultimate Sport Drink? Possibly not.....

Tue, 24 Apr 2022 10:26:00 GMT

We were interested to read an announcement that someone in the US has created the "ultimate sports drink" with its own spin on the ideal electrolyte mix

http://www.thenewsstar.com/article/20120422/NEWS01/204220315.

This time, the EX5 drink puts in a much higher level of potassium than seen in most sports drink - in fact 7x higher than Gatorade and almost 9x higher than Powerade. It's an interesting concept because unlike appropriate sodium supplementation, nowhere in the scientific literature has it ever been demonstrated that potassium supplementation in sports hydration confers any benefit.

What's more, average sweat losses of potassium are 150 mmol/L so it would take around 16 litres of sweat to become potassium deficient and that's not likely to happen in a typical training session or race no matter how hot it is if you're eating a regular diet. We're not really big believers in this one.......not with a potassium load that high and a sodium load of only 5 mmol/L. The lowest sodium loss we've tested in over 300 tests done in house on athletes is 19 mmol/L so there is no way EX5 will replace losses of the lowest salt sweater....

Hydration at the Malaysian Grand Prix.....

Tue, 27 Mar 2023 16:10:00 GMT

The Malaysian Formula 1 GP is considered to be the toughest race on the F1 calendar with the heat and humidity taking its toll on the drivers and race crew. Not surprisingly, according to a recent press release Lucozade prepared a special race formulation drink specific to the Mclaren drivers Button and Hamilton http://paddocktalk.com/news/html/story-186284. Helen Cowie, Technical Director, GlaxoSmithKline Research & Development admits that '....drivers can lose up to three kilos in sweat – roughly five per cent of their body weight......' But as the drivers are restricted to 1 litre of drink in the cockpit it is imperative that every drop contributes to performance.

Although the article is based upon science and supports the basis of what we do at Precision Hydration, it fails to mention that Button and Hamilton (and for that matter every single F1 driver on the start grid) have sweat sodium losses that are genetically determined and vary upto 8-fold. Getting this sodium content in the drink is important as sodium is what determines retention of water in the body. Bespoke hydration in motorsport is not exclusive to Lucozade either as at Precision Hydration we've been doing it since 2009. In fact our very first client was an endurance rally driver from Kenya who would typically almost pass out on Day 2 or 3 in the heat despite drinking litres of water. He was tested using the Precision Hydration sweat sodium analysis system and found to be a very high sodium sweater. With drinking water alone he would dilute his blood sodium leading to water intoxication (mild hyponatraemia). On bespoke sodium replacement drinks he is now extremely competitive. Since his success our regular clients include Tuthills Porsche Team, David Brabham (ex-F1 and Le Mans winner) and Bradley Smith in Moto2 as well as numerous drivers in GT racing and rallying where the cockpit temperatures can be incredibly high.

Hyponatraemia in marathon running; featured in the Telegraph - comments from Dr Jutley...

Mon, 26 Mar 2023 13:36:00 GMT

Taken from the Telegraph 26th March 2012:

http://www.telegraph.co.uk/health/dietandfitness/9163138/Over-drinking-can-be-deadlier-than-dehydration.html

The article reports the dangers of over-drinking which it claims 'can be deadlier than dehydration'. The article is actually talking about a potentially fatal but little recognised condition called Exercise Associated Hyponatraemia (EAH) or 'water intoxication' where athletes develop low sodium levels in their blood. This comes about from replacing sweat sodium losses with low sodium drinks or worse still water alone. With EAH water moves into the brain causing swelling. The athlete typically suffers from poor coordination, confusion, vomiting and often collapse.

A study published only this year by two London universities showed that 12% of London Marathon runners were planning on a drinking strategy that put them at risk of EAH and that only 35% actually understood its cause and effects.

So how do you go about preventing it? Firstly you have to understand who is at risk of developing it and what conditions predispose to it. The table below shows these factors (ref: Rosner and Kirven, CJASN, 2007)

Exercise duration >4 h or slow running/exercise pace

Female gender (may be explained by lower body weight)

Low body weight

Excessive drinking (>1.5 L/h) during the event

Pre-exercise overhydration

Abundant availability of drinking fluids at the event

Nonsteroidal anti-inflammatory drugs (not all studies)

Extreme hot or cold environment

The other crucial factor (not really mentioned in the Telegraph article) is to appreciate how much sodium you are losing in every litre of sweat.

You can either have this done at a lab using absorbent patches applied to your body which are then sent off to the lab for analysis once you saturate them with sweat. Alternatively you can have a Precision Hydration sweat analysis done at our centres http://www.myh2pro.com/sweat-testing in UK or Canada and soon in New Zealand. For those unable to take the test we can also estimate what your losses are via a quick questionnaire.

Call us on +44(0)1273 900277 and we can take you through this over the 'phone.

The results allow us to recommend which H2Pro Hydrate product should be right for you. From our own work and current published work the average athlete's sweat sodium loss per litre is 920 mg. Considering that most sports drinks provide far less than this (Hi-5 Zero provides 500mg/litre; Gatorade 450mg/litre; Powerade 225mg/litre for example) you can understand why even drinking these can result in net sodium loss with the risk of developing EAH. We avoid this problem by supplying drinks with 250, 500, 1000 and 1500 mg of sodium per litre to cater for all athletes so EAH is less of a possibility....

Coconut water as a sports drink....Dr Jutley's thoughts.....UPDATED

Sun, 11 Mar 2023 00:00:00 GMT

Since writing this post the following email landed in my inbox. It seems the Consumer Law Group (CLG) have filed a suit against a coconut water company for making claims that it is a good substitute for a sports drink:

Consumer Law Group files lawsuit against Vita Coco

Rebecca Prescott 12 Mar 2012

Consumer Law Group (CLG) has launched a national class action lawsuit against All Market on behalf of individuals who have purchased the product Vita Coco coconut water.

CLG has said that the class action involves the deceptive, misleading, false, and unfair advertising of Vita Coco as an electrolyte induced beverage similar to a sports drink.

In fact, in an independent study it was found that Vita Coco Coconut Water did not contain the amount of nutrients specified on the product’s label. In tests, it was sown that there was 40% less sodium than advertised (only 18mg out of its listed 30mg), 35% less magnesium (only 20.80 out of its listed 32mg), and 16% less potassium (only 432.60 out of its listed 515mg)

In addition, Vita Coco contains much less sodium than a sports drink, which is the key mineral lost during sweating and is, therefore, not effective for sports recovery, the group said.

Therefore, consumers of Vita Coco would not have agreed to buy a product which does not contain the level of nutrients that was represented to them and certainly would not have consented to pay a premium price for it, according to CLG.

Source: CLG

See also: Lawsuit filed against Vita Coco manufacturer

I felt compelled to post this in response to an article I saw entitled:

DITCH THE SPORTS DRINKS: COCONUT WATER IS NATURES WAY TO REHYDRATE.

See http://frugivoremag.com/2012/03/ditch-the-sports-drink-coconut-water-is-natures-way-to-rehydrate/

We're seeing coconut water touted as 'natures electrolyte' more and more often I'm really not sure about this! The article does make some valid observations about the high energy/sugar content of some sports drinks not being needed when you are not training hard but the comments on electrolyte balance are not completely accurate.

While coconut water may be natural I'm not convinced that its the best way to hydrate before, during and after exercise. For very gentle sessions perhaps it might be ok once in a while but I certainly wouldn't be telling anyone to ditch the sports drinks as recommended by the author. The article does advise against drinking too much to avoid over-hydration and hyponatraemia (low blood sodium) which it admits can be life-threatening (very true). However, coconut water typically contains only 160mg sodium per litre which is much less than the average sweat sodium losses in humans of around 920 mg per litre so the issue of hyponatraemia is not really avoided by using it. Then there's the high potassium content (Potassium is not a bad thing in reasonable quantities in protecting against diabetes and high blood pressure) but one litre of coconut water contains over 60% of your daily potassium requirements. In long hot events if used as a primary hydrator, even with 3 litres the total potassium load will be 1.8 times the daily requirement plus whatever is taken via sports gels and normal food intake. I use Potassium to stop the heart during cardiac surgery so would be extremely hesitant in advising people to drink large volumes of a potassium rich drink when exercising hard or sweating a lot.

The bottom line is that sodium, not potassium, is the key electrolyte you need to replace when sweating and this is summed up nicely with the quote below:

"The only electrolyte added to drinks consumed during exercise that is known to confer physiological benefit is sodium.”

Report of the Scientific Committee on Food on composition and specification of food intended to meet the expenditure of intense muscular effort, especially for sportsmen. 2001.

Dr Raj Jutley. CMO Precision Hydration ltd.

Sweat, sodium, sea and surfski

Sat, 11 Feb 2023 11:43:00 GMT

http://www.surfski.info/races/aus-nz/item/1385-jacobs-rubs-salt-into-doctors-wounds.html

This recent article on surfski.info really jumped out at us for a couple of reasons; firstly because a few of us at Precision Hydration have got into this exciting and growing sport in the last few years and secondly because it ties in so appropriately with what we’re trying to do with our sweat testing and H2Pro Hydrate drinks.

To set the scene: International long distance surfski racing pulls together some of the best flatwater kayak paddlers in the world, many of the greats of surf lifesaving and a small but talented band of professional full time Surfski paddlers from around the world.

Races take place over distances from about 10km up to 50km on the ocean in very fast but unstable boats, with paddlers constantly chasing waves to increase speed and push for the lead. Often the environment is hot (Australia, South Africa, Middle East) and the races can last upwards of 2hrs – exposing the paddlers to a lot of heat stress and sweat loss. ‘The Doctor’ in Perth at 27km is one of the major events in the surf ski calendar.

In the 2012 Doctor Tim Jacobs (Pro Aussie ski paddler) and Australian surfski racing legend and Clint Robinson (also an Olympic Gold Medallist in from 1992 amazingly challenging for a spot in the Australian team for London 2012!) were duking it out for the lead with Jacobs eventually taking the win and Robinson dropping back to just 7th near the end.

It’s interesting to note that Clint was leading for a good part of the race but towards the end was losing power and starting to get cramp in his forearms; symptoms that often accompany electrolyte depletion. In his post race interview Tim credited the fact that he’d been taking sodium capsules before the event to load up on his electrolyte stores and maybe that had made the crucial difference? Even Clint said he’d consider taking them next time having talked to Jacobs after the race….

What do we think happened?
It does seem likely that Clint’s cramps and slow down could have been electrolyte depletion related due to the hot conditions and high intensity of the race…See this Gatorade article about the link between cramping and sodium:

Although Tim’s sodium tablet approach got through the day this time around it is still something of a hit and miss approach using those things – especially given the risk of gastrointestinal upset that can occur if you get the tablet/fluid intake wrong or take too many capsules….

What we also don’t know too is how much difference there is between the amount of electrolyte and fluid they are both losing when racing see this article that highlights the potential differences.

So if Clint did decide to copy Tim’s regime next time round there’s nothing to say it would work as well for him, given his own physiology…

The huge differences we see in sweat sodium levels across the population

Our position? – with a quick test to identify their own unique sweat physiology and appropriate electrolyte replacement both Tim and Clint could be replacing exactly what they need during the race. Leaving Clint to finish as strong as he started it and Tim to finish without the risk of gastrointestinal issues associated with popping salt capsules as well as avoiding the long-term health risk of taking excess sodium.

We’ll bring our sweat testing kit to the European races if you’re there guys!

How can a sports drink possibly hydrate better than water?

Sat, 11 Feb 2023 03:29:00 GMT

On 4th January 2012, the Advertising Standards Agency (ASA) met to consider complaints that Powerade ION4 as advertised by Jessica Ennis, World and European Heptathlon Champion, was making claims that were misleading. According to the advert and Ennis’ testimonial it was claimed that Powerade ION4 ‘hydrates (me) better than water’. The ASA considered evidence from Coca Cola Great Britain as well as published scientific evidence and experts and the hydration claim was accepted (see http://www.asa.org.uk/ASA-action/Adjudications/2012/1/Beverage-Services-Ltd/SHP_ADJ_156530.aspx for adjudication details.

How can anything possibly hydrate better than water? Surely hydration and water are synonymous? While intuitively one would think so, it’s not that simple. For the body to be better hydrated the drink has to retained by the body. When comparing to another drink this can be shown simply by an increase in body weight with less urine production. A more complex method using blood sampling (Dill and Costill method) is used to show an increase in plasma volume. The benefits of improved hydration in sport are indisputable, especially in the context of intense exercise as Coca Cola GB took great pains to explain during the adjudication.

Almost all scientific trials looking at which drink hydrates better involve a cross-over design. An athlete is randomly exposed to one drink and tested under controlled conditions with a standard exercise regime often in a climate chamber. The test is then repeated usually 2-3 weeks later with the second drink being evaluated. Quite a few such trials have been published with convincing evidence that electrolyte containing drinks result in better retention as evidenced by increased body weight and plasma volume. The electrolyte responsible for this retention is sodium – in fact the only electrolyte so far recognized scientifically to confer any benefit in rehydration. The drinks also tend to typically contain around 6% carbohydrate for energy as well as promote water uptake in the gut.

Our own Precision Hydration trials in elite athletes have replicated these findings. 72 hrs ad libitum drinking of an electrolyte drink specific to sweat sodium losses compared to Evian water showed that our electrolyte drinks (H2ProHydrate) containing zero carbohydrates resulted in a weight gain of around 0.72 kg (1% increase) with the greatest fluid retention seen in those who lost most salt in their sweat (1.72%). One would think that weight gain translated to poorer performance. But as published scientific evidence has shown, this increased fluid retention results in improved performance. In our trials we saw a 7.3% power output increase across all the athletes while on H2ProHydrate with peak gains of 23% seen in high salt sweaters who retained the most fluid.

All in all the addition of electrolytes, primarily sodium, to water makes it a better hydrator than water alone by a magnitude of around 11-20% (although claims of up to 40% have been made by some). Being better hydrated increases weight slightly but the performance gains seen far outweigh this.

So it is good to see that sometimes sports drink marketing messages are more than just hype – although the fact that people contest marketers claims so vigorously in court does go to show how much mistrust there is of advertising these days….even when it is telling the truth!

Dr Raj Jutley
Chief Medical Office

Salt Friend or Foe

Sun, 29 Jan 2023 00:00:00 GMT

I was forwarded this article the other day http://www.ericcressey.com/sodium-intake-is-salt-bad-for-you and thought it was time to respond to the question ‘Is salt bad for us?’ as it is something I get asked about very frequently; especially in relation to sports people. Whilst there’s never going to be a totally conclusive answer my thoughts are laid out below…

Salt - Friend or Foe?

In my role as a medic almost everyday I tell patients that their coronary artery disease is down to 5 major risk factors - high cholesterol, diabetes, smoking, high blood pressure (hypertension) and genetics. Some have all risk factors and some have none. But almost all who have hypertension are on a low salt diet. Imagine how shocked they would be if they looked at published scientific evidence and discovered that in fact a low sodium diet actually gives them a HIGHER risk of dying from cardiovascular disease? The US-based National Health and Nutrition Examination Survey (NHANES I) study published in 1998 showed that a low sodium diet is associated with a 20% higher risk of death. The NAHNES II published in the Amercian Journal of Medicine much later http://www.jhsph.edu/bin/s/m/May_9_2006.pdf went to on show that an intake of less than 2300mg sodium/day was associated with a higher risk of death from cardiovascular disease.

So what's all this hype about? Well, to put it simply salt metabolism, intake, excretion, physiology are extremely complex. They get even more complex in disease states such as hypertension and heart disease so prescribing bold cut-off points for what is arguably the most important mineral in the body will simply not work for everyone. What has not helped is that over decades the threshold of who is hypertensive has lowered making many 'normal' people now either patients or potential patients. There is no doubt that reducing salt will reduce blood pressure slightly BUT if you collate all the evidence as was done during a meta-analysis of 58 trials by Graudal in 1998, the conclusion is that the clinical benefit is so weak that the authors state the 'results do not support a general recommendation to reduce sodium intake'. It is generally agreed reduction of salt intake can be used as supplementary treatment but if you examine the literature closely the reduction by lowering salt intake is not more than can be acheived by eating a high omega-3 fatty acid diet or weight reduction or in fact relaxation therapy.

So my take on the matter.......! Eat sensibly and eat enough salt - not too much and certainly not too little, especially if ou are an athlete and sweating a lot. Avoid PROCESSED food that contain far too much salt- you'll be horrified to see how mcuh a can of tomato soup or even a slice of bread contains. REPLACE what you lose when exercising using an electrolyte drink matched to your rate of loss. Your sodium losses will predominantly be via sweat, as little as 100 ml/24 hr in normal weather, 20 degree C and no exercise and as much as 5000ml/24hr in warm weather, 29 degree C with exercise in the same person. Research shows that human sweat sodium losses vary as much as 10-fold in humans. So figure out how much sodium you lose and simply REPLACE it like for like.