Do you like it on your back? In your hand? Or around your waist?

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With temperatures rising and longer lighter days for many of us in Europe and North America, we can hopefully all get out and run more. But as we all know, or maybe we don’t, we need to consider several things when running in the heat:

  • It’s harder
  • You sweat more
  • You need more fluid

We need to adapt. So what happens when the mercury rises?

Question, do you prefer it:

  •  On your back?
  •  In your hand?
  •  Around your waist?

Of course I am talking about your method of hydration.

 

READ THE FULL ARTICLE ON RUNULTRA HERE

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Race Day Nutrition (Part Five) – Marc Laithwaite

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Your body needs fluids for various functions. Body cells and tissues are filled with fluid, the nervous system requires fluid and the fluid component of your blood (known as plasma) is also affected by your drinking habits. Exercise leads to a loss of body fluids via sweating and breathing and this loss of fluid can eventually lead to what is commonly termed dehydration.

What happens when we drink?

When you put fluids into your stomach, they pass through the stomach wall into your blood vessels and effectively become plasma. As your blood stream can pretty much reach any part of your body, any tissue or any cell, this fluid can be transferred from the blood stream into the tissues or cells.

How does fluid actually pass from one place to another?

To get the fluid from your stomach into your blood stream or from your blood stream into tissue cells requires a process termed ‘osmosis’. Salt acts like a magnet drawing fluid towards it and the concentration of salt in your blood and tissues determines the shift of fluid around your body. When you take a drink of water it reaches your stomach and waits to pass through the wall into your blood stream. Your blood is saltier than the water in your stomach and due to the higher level of salt in the blood, the water is drawn from the stomach, through the wall and into the blood. This water effectively becomes blood plasma and travels around your body. If it finds muscle tissue, which has a higher salt concentration, the ‘magnetic’ pull of the salt within the muscle will draw the fluid from the blood into the muscle.

In simple terms, when something is dehydrated, it becomes salty. By becoming salty it’s magnetic or ‘osmotic’ pull increases in power and it attracts water towards it. That’s how fluid shift and hydration works within the body, that’s ‘osmosis’.

So how much should I drink?

Most guides will recommend somewhere between 1 – 1.5 litres per hour depending upon individual sweat rates, but it is unlikely that this amount can actually be absorbed when you are exercising. As each litre of fluid weight 1kg in weight, it is possible to calculate (very roughly) fluid loss by taking weight before and after and this will give you an estimation of how much you need to drink. This is a relatively simple process, go and ride or run for a couple of hours at the same intensity as your upcoming event and wear the same clothing etc. Weigh yourself before you go out, weigh yourself when you get back and then note how much fluid you drank. For example:

Weight beforehand: 80kg
Weight afterwards: 78.4kg
Weight lost: 1.6kg
Drink taken: 500ml (500g/0.5kg) – add this on
Actual weight lost: 2.1kg

*You should also take into account urination, if you stop for a pee during the session, that should be added to the loss!

Drinking too much is worse that not drinking enough:

For many years marathon runners were encourage to drink at every aid station and the key phrase was often “don’t wait until you’re thirsty, it’s too late then!” Unfortunately a few of those people died as a consequence due to a condition known as ‘hyponatremia’, which is excessive dilution of body salts. There needs to be some common sense applied to hydration. Your body tells you when you need fluid by making you feel thirsty and then you should drink however much you’ve lost. Your body operates very much like a water tank with an overflow system. Once the tank is full, any further fluid will be dispensed with by a visit to the toilet! It’s correct to say that urinating frequently and especially if the urine is clear, is not a sign of optimal hydration, it’s a sign you’re drinking too much.

Hyponatremia can be explained in this simple manner:

Take 1 medium sized bucket and add a teaspoon of salt and a pint of water to create a salt solution. Add another pint of pure water to the same bucket and you have now diluted the salt solution (it’s a bit weaker). Add another pint of pure water to the same bucket and dilute the salt even further. Keep going until the salt solution is so weak you can hardly even taste the salt. We said earlier in this article that salt acts like a magnet and attracts water towards it:

‘When you take a drink of water it reaches your stomach and waits to pass through the wall into your blood stream. Your blood is saltier than the water in your stomach and due to the higher level of salt in the blood, the water is drawn from the stomach, through the wall and into the blood’

What if you added so much water to your body that the blood wasn’t salty at all, it was diluted so much that it lost all its pulling power?

Salt intake:

Salt intake is a big question for many athletes and the basic guidelines tend to be relatively poor. Some people sweat more than others and the weather conditions will obviously have a large bearing upon both sweat and salt loss, but let’s examine the basics. Each litre of sweat contains 2.5-3.5g of salt depending upon the individual and how well acclimatised you are to hot conditions. IMPORTANT: Salt and sodium are 2 completely different things and we are interested in SODIUM’ and not ‘SALT’. Salt is 2 parts sodium and 3 parts chloride, so 2.5g of salt = 1g sodium / 1.5g chloride.

As a simple example, a tea spoon of salt = 6 grams. The 6 grams is made up of 2.4g sodium and 3.6g chloride.

Let’s presume that you are going to sweat 1 litre every hour (you need to do the calculation from taking weight before and after) and you sweat 2.5g SALT each litre, that means you sweat 1g SODIUM every hour.

Ok, so you’re sweating 2.5g SALT and 1g SODIUM every hour, so a tea spoon of salt (6 grams as explained above) would be enough for somewhere between 2 – 2.5 hours. Most sports drinks don’t have that much salt / sodium in them, so unless you take this into account, it’s likely in a long distance endurance event, your sodium levels will drop. The body does adapt by reducing the loss of sodium (it’s thins your sweat by reducing salt/sodium), but in hot conditions, your sodium intake needs to be addressed.

Remember the isotonic issue:

We said in last week’s blog that fluid intake is important when you are eating food, to ensure that the solution in your stomach is not too concentrated. For this reason, you need to consider fluid and food intake together. If you calculate that you are sweating 1 litre per hour and your planned intake of carbohydrate is 60g per hour, then that ‘technically’ gives you a 6% solution (1000ml / 60g = 6%). The timing of you fluid should be influenced by food intake, for example, if you eat half an energy bar, take fluid with it to dilute the solution. If you missed last week’s blog (part 4) which discussed carbohydrate solutions, click the nutrition link on the left hand blog menu and you’ll find it there.

Practical application of hydration strategies:

  1. If you’re urinating frequently and it’s clear, you may be drinking too much.
  2. Bloated stomach is one of the first signs of hyponatremia, coupled with vomiting liquid. Headaches are also a common symptom.
  3. Use electrolyte tablets in hot weather, but understand that hyponatremia is generated by too much fluid, as opposed to not enough salt. You should also check your energy bars or gels as many of them have salts included.
  4. Use thirst and urine colour as indicators of hydration status. Very dark, infrequent urine is a sign of dehydration.
  5. Weigh yourself before and after exercise as a simple guide to fluid loss, each litre of water weight 1kg, each millilitre weighs 1g.
  6. Try to incorporate food or energy intake as part of your hydration strategy and consider solution strength (isotonic)
  7. If you suffer from bloated stomach due to hyponatremia, don’t take more water, take more salt
  8. People with hyponatremia often don’t urinate, don’t confuse this with dehydration

– Marc

About Marc:

Sports Science lecturer for 10 years at St Helens HE College.

2004 established The Endurance Coach LTD sports science and coaching business. Worked with British Cycling as physiology support 2008-2008. Previous Triathlon England Regional Academy Head Coach, North West.

In 2006 established Epic Events Management LTD. Now one of the largest event companies in the NW, organising a range of triathlon, swimming and cycling events. EPIC EVENTS also encompasses Montane Trail 26 and Petzl Night Runner events.

In 2010 established Montane Lakeland 50 & 100 LTD. This has now become the UKs leading ultra distance trail running event.

In 2010 established The Endurance Store triathlon, trail running and open water swimming store. Based in Appley Bridge, Wigan, we are the North West’s community store, organising and supporting local athletes and local events.

Check out the endurance store HERE

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NSAIDs and Sport

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NSAID (Non-steroidal anti-inflammatory drug) and Sport

How many of you have gone for a run with a Non-Steroidal Anti-Inflammatory Drug in your pocket for that ‘just in case’ scenario? Maybe you have taken a tablet before going for a run/ race to avoid potential issues? Or possibly you have taken a tablet post run to reduce swelling and inflamation?

It’s a common scenario and one that I am aware off continually when running and racing. I have done it myself… I remember racing and going through pain so I took an Ibuprofen only to be hit by stomach issues later in the race.

Earlier this year, Montane athlete, Marcus Scotney had severe issues post a great run at Iznik Ultra in Turkey. A situation that was potentially life threatening.

In an attempt to provide some clear information, I caught with the UK’s key specialist on kidney function, Dr Richard Fluck to find out what we should and shouldn’t do.

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IC – NSAIDs what are they?

RF – They are a class of drug that you can purchase over the counter. They are commonly used to treat pain and inflammation. The most common is Ibuprofen but others are available. They are anti-inflammatory.

IC – Let’s remove the sport element. What are the pros and cons of NSAIDs?

RF – Any tablet, has risk and benefit. We need to weigh up the balances. A medical approach to medication is that any drug must be tested, assessed for safety and so on. NSAIDs are really used for arthritis and so on. They have been increasingly used as a method of pain relief. In more recent times, particularly in the UK, you can now buy these drugs over the counter. We are bombarded by adverts on the TV telling us how good they are. So, the tablets are there for a reason. The question is, are you taking them appropriately? NSAIDs are well studied and they have side effects, anyone who takes them needs to be aware of this.

IC – From a runner’s perspective, I am pretty sure we all know someone who has taken Ibuprofen before a race, during a race or post a race to reduce inflammation. Are any of those scenarios ok?

RF – We need to know individual scenarios to be specific, however, I would say all the above scenarios bring a risk. Endurance sport and NSAIDs interfere with the normal regulation of your body. For me as a kidney expert, my concern is with the kidneys. What do NSAIDs do to the kidneys? Kidneys allow us to pass urine, they regulate the water in our body and they regulate salt, particularly sodium and potassium and they regulate toxins that come from everyday life. Of course the kidneys do have other functions… they look after your bones in regard to vitamin D, they regulate blood pressure via hormonal systems and they stimulate bone marrow to boost red blood cells. If the kidneys go wrong it is usually the first category that fails first, so, liquid and salt/ toxin regulation. Now, lets take an individual, I was listening to a chat re football and football players playing in hot climates. It was a chat about regulating salt and water. It can be tricky to judge and get this right. So, the peril for an individual is that they get it wrong one way or the other. It’s particular more of a problem for slower runners. The tendency is not to drink enough or drink too much. For example, Hyponatremia (people over drinking) and not thinking of electrolytes.) So, our kidneys work to help with dehydration or over hydration. The kidney kicks in and helps control this. It’s about regulating salt and water. This is where NSAIDs come in as they can inhibit this. So, if a runner pre loads, takes during or after running and the kidney needs to work then the action can be blocked! So, the danger is that you hang on to fluid, hang on to salts or in fact you increase fluid loss (you pass more urine.)

IC – Lets talk about some scenarios that we can relate to.

RF – So, I told you about fluid… lets talk about salt (sodium and potassium.) So, Hyponatremia (low sodium) is more common in people who take NSAIDs. It’s a real danger. Potassium is less known about, it has low levels in the blood as most is stored in our cells. Potassium for example will know it is in bananas. Potassium is important. NSAIDs can block the kidneys function in controlling potassium levels. I have treated runners in endurance situations where runners have become dehydrated, the kidneys have not worked and potassium levels are high. High potassium can stop your heart! So, I am not trying to terrify anyone but you have important issues to consider.

IC – What are the implications in an ultra event? For example, an event that lasts so much longer than a marathon; hours-and-hours of running. It is possible to pop a NSAID every 4-hours?

RF – The recommendation (RDA) is 400mg 3-times a day! However, I have heard scenarios where people double this dose, for example at Marathon des Sables. That is really going to suppress hormonal mechanisms. If you are a 4-hour runner, you may get away with it but 4-hour does seem to be a cut off point. Obviously, anyone who is out for 4-hours plus has a much greater opportunity to cause issues and problems in regard to salt/ water balance. This risk increases if you bring NSAIDs into the scenario.

IC – I read some research about Western States and it showed that frequent use of drugs caused colonic seepage, what does that do/ mean? Read HERE)

RF – It’s more about the gut! It is interesting because one of the national papers in the UK discussed a scenario about a runner who died on a course. It was a problem with the bowel. I concentrate on kidneys but NSAIDs have wider actions for the whole of your body. NSAIDs can cause ulcers, indigestion and all sorts of mayhem and impact on your bowel. The other interesting thing is that in chronic usage they have an impact on the heart. So, you may be aware of public interest in side effects in some of the newer drugs. How that is mediated I wouldn’t wish to go into it here but one needs to be aware of these things, in particular blood pressure and heart. You know, if you take a tablet a day I wouldn’t recommend it.

IC – What about animal studies that show that NSAIDs can hamper muscle regeneration? (Read HERE)

RF – I need to concentrate on the kidneys. It is my specialisation. Interesting you raise muscles though… if you do a simple search on the web, you will find many cases were people describe kidney failure in ultras. I remember a guy (a runner) who mentioned runners at Western States in the 90’s and his story of acute renal failure is typical of the very severe (but rare) cases were people have total kidney shut down for days or weeks. It can lead to continual problems for example with blood pressure. And that comes about from a combination: First they may be running in unusual circumstances, climate and weather for example. It may be that they are not prepared and they get muscle pain and so they take a NSAID. What happens is that muscle breakdown occurs and that releases a protein into the body called Myoglobin. Our kidneys work by filtering our blood. Myoglobin goes around the body in blood circulation. The kidneys try to eradicate this but it can’t because it isn’t designed to do that! The kidney clogs up and blocks. This is a really dangerous situation.

IC – This is the situation that happened with Montane athlete, Marcus Scotney at Iznik Ultra. He raced a 130km race and I believe he took six NSAID during the race. When he returned to the UK, he felt rough. He went to the doctors and then was submitted to hospital. He had Myoglobin in his kidneys. How serious is that?

RF – It can be life threatening! For example, if Myoglobin is present your urine may well look like Coca Cola (dark brown or black.) Ironically, the kidneys will not have any pain, well, they will give pain but at a very late stage. At this point, your kidneys are just not functioning so you can get into serious trouble particularly if eating and drinking in normal way. I have a scenario of one gentleman who had 50-pints of liquid in his body… this liquid went to his lungs and he couldn’t breathe. He was drowning internally! You can end up in intensive care. The potassium side of things, remember potassium is stored in the cells. Myoglobin is reduced into the blood so potassium levels can become very high, very quickly and I am afraid that can lead to sudden death with no warning.

IC – In Marcus’ case. He was in hospital would they have used dialysis?

RF – I am sure Marcus had great treatment; he may have needed temporary dialysis. I remember a story of a soldier who was on a march with a heavy pack, minimal liquid and so on… he ended up on dialysis.

IC – We have built up a picture here of fear! Is this doom and gloom correct? Do scenarios exist when an NSAID is okay? 

RF – I have painted a picture of terrible scenarios. I have given you the worse case scenario. Please keep in mind that most people do sensible distances for running. The kidney is very forgiving as is the rest of our body. For example, I have taken a NSAID on a run… I have been careful on my drinking, I have been careful that I have passed urine and I have monitored urine colour. These basics can help. The question is; why are you taking the NSAID? Professionals for example can have experts and experience around them; this is very different to an everyday runner. If you are on a very long race, Paracetemol is a safer drug if used sensibly and within RDA guidelines. However, caution is required! However, Paracetemol address mechanical pain and not inflammation.

IC – Interesting that a kidney specialist has taken a NSAID when running. How do you justify that?

RF – I would not pre load with NSAIDs. No evidence that this works. If you have mechanical pain, Paracetemol is better taken sensibly. However, post race if you have inflammation a NSAID may be sensible but you need to monitor urine and keep within RDA. If you feel unwell, you need to seek attention; sooner than later. Be sensible and prepare for a run/ race accordingly. Weighing yourself is actually a good thing for monitoring fluid.

IC – Races like Western States still weigh runners during the race.

RF – That is a reasonable strategy to consider.

IC – Final point I would like to consider, we looked at the doom and gloom scenario and then we have said that knowledge is paramount. But my reaction is, don’t take anything. Ultra runners are not the most clear thinking individuals at 10, 15 and 20+ hours into a race. I remember Marcus saying that he urinated dark urine in the race but still pushed to the finish line… Other than weighing a runner is there anything we can do?

RF – We are getting into medical testing now. That is not practical or sensible for racing. We would need to blood test, we would need to test urine and so on. It just wouldn’t work. You are quite right, we need to take personal responsibility and assess risk against benefit. But do this within an envelope of understanding. I look at my own body and what I can tolerate. Be sensible! Also, other runners need to look after other runners. We need corporate responsibility when running or racing.

More reading:

Read about NSAIDs at Western States HERE

Ibuprofen administration during endurance training cancels running-distance-dependent adaptations of skeletal muscle in mice. HERE

When is it ok to take a NSAID?

During the first 2 to 3-days of an acute injury, taking a NSAID is advised but once you exceed this window, general advice is let your body do the work! It will naturally heal.

Niggling injury pre training or racing? Worried about ‘possible’ pain while running or racing? No evidence shows that a NSAID will be a benefit you and as discussed above, a NSAID may very well hinder your run or race.

Be sensible and keep running or any sport you do natural… a NSAID shouldn’t be required to get you to the finish line!

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Fluck, Richard. 00-190902

Who is Dr Richard Fluck?

Richard Fluck trained at Trinity Hall, Cambridge and the London Hospital Medical College, qualifying in 1985. Early training was undertaken in the East London area before moving into research at St Bartholomew’s Hospital. He was appointed a British Heart Foundation fellow whilst exploring the link between cardiovascular disease, calcium signalling and abnormalities of calcium metabolism in chronic kidney disease. He returned to the Royal London Hospital as Lecturer and honorary Senior Registrar in Nephrology.
In 1996 he took up post at Derby City Hospital as a single-handed nephrologist. Over the next decade, the department expanded, developing a strong clinical research and safety programme. It has interests in cardiovascular consequences of CKD and dialysis, infection and vascular access. He is involved in the coordination of two cohort studies looking at CKD in primary care (RRID) and the consequences of AKI (ARID). More recent projects include the development of PROMs for renal patients and developing home therapies for patients on dialysis.

Within the acute trust he was clinical lead for renal disease for 15 years and clinical director for medicine, then clinical lead for the East Midlands Renal Network and worked with the DH and HPA on infection in renal disease. He was also the clinical lead for the Kidney Care National audit on vascular access and transport in the haemodialysis population. He was appointed NCD (Renal) April 2013.

He is the immediate past president of the British Renal Society, chair of the Kidney Alliance, on the UK Renal Registry Board, is the UK country co-investigator for the Dialysis Outcomes and Practice Patterns Study (DOPPS) and is on the editorial board of Nephron. In 2007, the unit won the Renal Team of the year award, given by Hospital Doctor and the following year received the Health and Social care award for safety in patient care.

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NSAID – Non-steroidal anti-inflammatory drug

The term nonsteroidal distinguishes these drugs from steroids, which, among a broad range of other effects, have a similar eicosanoid-depressing, anti-inflammatory action. As analgesics, NSAIDs are unusual in that they are non-narcotic and thus are used as a non-addictive alternative to narcotics.

The most prominent members of this group of drugs, aspirin, ibuprofen and naproxen, are all available over the counter in most countries. Paracetamol (acetaminophen) is generally not considered an NSAID because it has only little anti-inflammatory activity. It treats pain mainly by blocking COX-2 mostly in the central nervous system, but not much in the rest of the body.

NSAIDs inhibit the activity of both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), and thereby, the synthesis of prostaglandins and thromboxanes. It is thought that inhibiting COX-2 leads to the anti-inflammatory, analgesic and antipyretic effects and that those NSAIDs also inhibiting COX-1, particularly aspirin, may cause gastrointestinal bleeding and ulcers. For this reason, the advantages of COX-2 selective inhibitors may be indicated. ©wikipedia

Read about NSAIDs HERE 

Hyponatremia – is defined as a low sodium concentration in the blood. Too little sodium in the diet alone is very rarely the cause of hyponatremia, although it can promote hyponatremia indirectly and has been associated with Ecstasy-induced hyponatremia. Sodium loss can lead to a state of low blood volume, which serves as a signal for the release of anti-diuretic hormone (ADH). ADH release leads to water retention and dilution of the blood resulting in a low sodium concentration.

Exercise-associated hyponatremia (EAH) is common in marathon runners and participants of other endurance events.13% of the athletes who finished the 2002 Boston Marathon were in a hyponatremic state, i.e. their salt levels in their blood had fallen below usual levels.

Sodium is the primary positively charged ion in the environment outside of the cell and cannot freely cross from the interstitial space into the cell. Charged sodium ions attract up to 25 water molecules around them thereby creating a large polar structure that is too large to pass through the cell membrane. Normal serum sodium levels are between approximately 135 and 145 mEq/liter (135 – 145 mmol/L). Hyponatremia is generally defined as a serum sodium level of less than 135 mEq/L and is considered severe when the serum sodium level is below 125 mEq/L.

Many conditions including congestive heart failure, liver failure, kidney failure and pneumonia are commonly associated with a low sodium concentration in the blood. This state can also be caused by over hydration from drinking too much water due to excess thirst (polydipsia). Contents ©wikipedia

Hydration

Wow! it would appear that Dr Tim Noakes and his ‘Waterlogged‘ book has caused some interest… not a surprise. I guess the whole reason for me initially posting was that I new that it would rock the boat and make us all look at what we do personally in regard to our own personal hydration when running or racing.

As part of Talk Ultra we have a regular section of the show called Talk Training – we look at our sport and we discuss all aspects of what will make us all better runners. Often our subjects and our thought processes may very well be controversial and thought provoking. Only recently we actually discussed this exact subject. You can listen HERE

However, Marc Laithwaite from Endurancecoach who is my co-host for Talk Training is far more experienced and a specialist in this field. I will let him tell it in his words:

An alternative view on hydration

Our focus is hydration or in more simple terms how much to drink.

Why drink?

Your body needs fluids for various functions. Body cells and tissues are filled with fluid, the nervous system requires fluid and the fluid component of your blood (known as plasma) is also affected by your drinking habits. Exercise leads to a loss of body fluids via sweating and breathing and this loss of fluid can eventually lead to what is commonly termed dehydration.

What happens when we drink?

When you put fluids into your stomach, they pass through the stomach wall into your blood vessels and effectively become plasma. As your blood stream can pretty much reach any part of your body, any tissue or any cell, this fluid can be transferred from the blood stream into the tissues or cells.

How does fluid actually pass from one place to another?

To get the fluid from your stomach into your blood stream or from your blood stream into tissue cells requires a process termed ‘osmosis’. Salt acts like a magnet drawing fluid towards it and the concentration of salt in your blood and tissues determines the shift of fluid around your body.

When you take a drink of water it reaches your stomach and waits excitedly to pass through the wall into your blood stream. Your blood is saltier than the water in your stomach and due to the higher level of salt in the blood, the water is drawn from the stomach, through the wall and into the blood. This water effectively becomes blood plasma and travels around your body. If it finds muscle tissue which has a higher salt concentration, the magnetic pull of the salt within the muscle will draw the fluid from the blood into the muscle.

In simple terms, when something is dehydrated, it becomes more salty. By becoming more salty it’s magnetic pull increases in power and it attracts water towards it. That’s how fluid shift and hydration works within the body, that’s ‘osmosis’.

What happens when you dehydrate?

When you dehydrate your tissues and blood have less fluid thereby making them more salty, in the hope that they can attract fluid towards them. Your blood becomes thicker as you still have the same amount of ‘blood cells’ but the fluid component is reduced, thereby making it more concentrated. Not only does the blood become thicker (making flow more difficult), the absolute amount of blood is also reduced so you have to pump the smaller blood volume more quickly around the body, thereby increasing heart rate.

Most text books will recommend somewhere between 1 – 1.5 litres per hour depending upon individual sweat rates, but it is unlikely that this amount can actually be absorbed when you are exercising. As each litre of fluid weight 1kg in weight, it is possible to calculate (very roughly!) fluid loss by taking weight before and after.

The Endurance Coach research on ultra distance runners

Last year we measured pre and post body weights for competitors taking part in a 100 mile mountain running event http://www.lakeland100.com. Race finish times varied from 24 to 40 hours and if we presume that athletes are losing 1-1.5 litres per hour, just how much weight did the competitors lose???!!

The body weight stats 2010

Our stats from last year showed the followed weight loss at the finish line:

  1. Runners sub 30 hours, average weight loss 860g / 860ml
  2. Runners sub 32 hours, average weight loss 1008g / 1008ml
  3. Runners sub 35 hours, average weight loss 1040g / 1040ml

Compare those figures to the guidance given in the previous paragraph which suggest that athletes will need to replace 1-1.5 litres per hour as this is the rate at which they are losing fluid. Admittedly the competitors may not be exercising at a very high intensity due to the nature of the event, but even then.. something doesn’t add up as the fastest runners haven’t even average 1 litre fluid loss at the finish.

Take the mineral water challenge.. we guarantee if you drink 5 litres per day we’ll feel great about our bank balance and you might end up in hospital..

I know.. I’m cynical.. However, there needs to be some common sense applied to hydration. Your body tells you when you need fluid by making you feel thirsty and then you should drink what you’ve lost. Your body is very much like a water tank with an overflow system, once the tank is full, any further fluid intake will be dispensed with by urinating. It’s correct to say that urinating frequently and especially if the urine is clear, IS NOT a sign of optimal hydration, it’s a sign you’re drinking too much.

The drink might kill you..

For many years marathon runners were encourage to drink at every aid station and “don’t wait until you’re thirsty.. it’s too late then!” Unfortunately a few of those people died as a consequence due to a condition known as ‘hyponatremia / hyponatraemia’ which is excessive dilution of body salts.

What’s going on??

Hyponatremia is quite simple:

  1. Take 1 medium sized bucket, add a tea spoon of salt and then add 1 pint of water and in your bucket you have a salt solution.
  2. Add another pint of pure water to the same bucket and you have now diluted the salt solution (it’s a bit weaker).
  3. Add another pint of pure water to the same bucket and dilute the salt even further.
  4. Keep going until the salt solution is so weak you can hardly even taste the salt.

We said earlier in this article that salt acts like a magnet and attracts water towards it:

‘When you take a drink of water it reaches your stomach and waits excitedly to pass through the wall into your blood stream. Your blood is saltier than the water in your stomach and due to the higher level of salt in the blood, the water is drawn from the stomach, through the wall and into the blood’

What if you’d added so much water to your body that the blood wasn’t salty at all, it was massively diluted and had thereby lost all its pulling power?

Stay calm..

The chances of anyone dying from hyponatremia are so minimal and so infrequent that this should never concern you but weight measurements before and after can be an important part of medical checks. In essence, if you collapse and you’ve lost weight, we’d give you a drink, some food and a lift back home. If a competitor were to collapse and following a weight check they had gained weight, we would take it more seriously.

Some of you may be thinking at this point that you can take salt tablets with your water, if you add salt and water simultaneously, problem solved! The research has shown that it’s not a lack of salt intake which leads to hyponatremia, it’s too much fluid.

In conclusion

Drink sensibly, let thirst guide you and don’t force load yourself with water.

Aside from excess fluid intake, there is one other thing which may lead to weight gain during ultra distance endurance events and that is ‘rhabdomyolysis’ or ‘muscle damage’ leading to inflammation. This is a real issue for longer events and has a huge impact upon performance and health.

Waterlogged – Tim Noakes, MD, DSc

Taken from the book – ‘Waterlogged’ by Tim Noakes

“Drink as much as you can, even before you feel thirsty.”  That’s been the mantra to athletes and coaches for the past three decades, and bottled water and sports drinks have flourished into billion-dollar industries in the same short time. The problem is that an overhydrated athlete is at a performance disadvantage and at risk of exercise-associated hyponatremia (EAH)–a potentially fatal condition.

Dr. Tim Noakes takes you inside the science of athlete hydration for a fascinating look at the human body’s need for water and how it uses the liquids it ingests. He also chronicles the shaky research that reported findings contrary to results in nearly all of Noakes’ extensive and since-confirmed studies.

In Waterlogged, Noakes sets the record straight, exposing the myths surrounding dehydration and presenting up-to-date hydration guidelines for endurance sport and prolonged training activities. Enough with oversold sports drinks and obsessing over water consumption before, during, and after every workout, he says. Time for the facts—and the prevention of any more needless fatalities.

An excellent article written by Joe Uhan is available on iRunFar and I recommend you read it as a follow on from the above ‘teaser’.