Bushwalk Australia

Saw a report on 60 Minutes the other week about Aussie deaths on Kokoda- it seems hikers are getting evac'ed or dying with loss of conciousness/seizures etc. A couple of Aussie doctors went to investigate and found that some hikers are drinking TOO MUCH water and leaving thier body with very low salt concentrations (hyponatraemia). One lady they tested who was borderline had drunk 10 litres- people are trying to do the right thing and stay hydrated especially in such hot/humid conditions of PNG. Apparently the same thing has happended to marathon runners. Very interesting story- so I guess we should not overdo the H20 annd add some gatoraide or the like. Interesting.....
Cheers Lizzy

In many cases I think it comes down to people not having enough long term experience with their bodies in exercise environments. They lead a sedentary lifestyle, get an idea in their heads and believe that with 6 months of walking around the block they can perform at a high level. They sweat in the field, think they need to replace only fluid, hence drink 10L of water due to either mis-information from others or their own ignorance or lack of knowledge.

When I say experience, I mean knowing what their body needs to perform and recover in race/adventure environmentsq, this can take years to develop and gain knowledge over a wide variety of temps, situations, physical and emotional stress etc.

Yes, elite athletes can suffer this too, however put it in perspective - these guys push their bodies to the extreme everyday in training and racing, in pursuit of the podium they can cross that fine line (or be on the gear too) of overexertion or make a mistake with hydration/fuel stops.

Preparation is key. Never go into a race/event dehydrated, tired, or under-recovered, because the event itself will magnify your preparation.

60 minutes and other media do not research/report the background of the individuals, mght be heavy alcohol or coffee drinkers - predisposes them to dehydration through the diuretic effect of these substances. There are always more facts in the background in each case.

Area54 wrote:In many cases I think it comes down to people not having enough long term experience with their bodies in exercise environments. They lead a sedentary lifestyle, get an idea in their heads and believe that with 6 months of walking around the block they can perform at a high level. They sweat in the field, think they need to replace only fluid, hence drink 10L of water due to either mis-information from others or their own ignorance or lack of knowledge.

When I say experience, I mean knowing what their body needs to perform and recover in race/adventure environmentsq, this can take years to develop and gain knowledge over a wide variety of temps, situations, physical and emotional stress etc.

Yes, elite athletes can suffer this too, however put it in perspective - these guys push their bodies to the extreme everyday in training and racing, in pursuit of the podium they can cross that fine line (or be on the gear too) of overexertion or make a mistake with hydration/fuel stops.

Preparation is key. Never go into a race/event dehydrated, tired, or under-recovered, because the event itself will magnify your preparation.

60 minutes and other media do not research/report the background of the individuals, mght be heavy alcohol or coffee drinkers - predisposes them to dehydration through the diuretic effect of these substances. There are always more facts in the background in each case.

Completely agree with all of the above!

Apart from ensuring I'm hydrated when I go out etc, as a general rule I start drinking water mixed with Endura after one hour of exercise (i.e., if the exercise lasts an hour or less I only take water; if it's longer than 1 hour I'll take one water bottle and one bottle with an Endura/water mix - generally slightly less concentrated than the label suggests). If out all day (e.g., day walk I take water with Endura tabs to add as needed). (Based on my experience with my body and it's response to exercise over the years).

I also agree that we definitely do not get the whole story from the media and indeed everyone has their own background /contributing factors. I was just pointing out that it is something to consider- especially for people unaware of the physiology of their bodies and not experienced in sport/training etc. A person such as this could easily drink vast amounts of water unawares of its potentially devastating impact- just thought it could be something for them to consider (the post was not meant to be targeted at you guys who already understand all this and no doubt ensure adequate electroyte replacement and appropriate training etc).

Lizzy wrote:I also agree that we definitely do not get the whole story from the media and indeed everyone has their own background /contributing factors. I was just pointing out that it is something to consider- especially for people unaware of the physiology of their bodies and not experienced in sport/training etc. A person such as this could easily drink vast amounts of water unawares of its potentially devastating impact- just thought it could be something for them to consider (the post was not meant to be targeted at you guys who already understand all this and no doubt ensure adequate electroyte replacement and appropriate training etc).

Hi Lizzy,

Agree it's a very good point to raise for the less experienced! Cases of Hyponatraemia amongst weekend warrior fun runners (as an example) are apparently all too common. People get the hydration message but are not so aware of what they should be drinking when - that message needs to be promoted just as loudly!

Cheers,

JB

Area54 wrote:In many cases I think it comes down to people not having enough long term experience with their bodies in exercise environments. They lead a sedentary lifestyle, get an idea in their heads and believe that with 6 months of walking around the block they can perform at a high level. They sweat in the field, think they need to replace only fluid, hence drink 10L of water due to either mis-information from others or their own ignorance or lack of knowledge.

I generally agree with this. I would point out that the majority of people doing Kokoda seem to be on organised jaunts, so even the most poorly prepared should be getting enough advice and support not to fall into this particular trap. Perhaps some of the tour operators are not living up to their advertised reputations? (surprise!)

I've done a bit of walking, but I cannot remember a day when I drank anything like 10L !

Don't know the full details however IMHO 10 liters of water on one walk is a total beat up as there is no way you could expire any way near that amount or pee it out (300 ml average pee) would mean that you would need to pee at least 30 times in one day,so IMHO you would drown with 10 Lt of water intake
corvus.

The more you drink the more you will pee; drinking 10L in a day is certainly possible if you're sweating heavily and making a concerted effort to refill.

I didn't watch the 60 minutes report but did read a story in the Fairfax weekend mag about a year ago; sounded as though the guides were trying to do the right thing with frequent scheduled drinking breaks but perhaps not taking enough notice of exactly how much individuals were drinking at these stops and in between.

10 lt of water per day ?? I stand by my comment that you would be hard pressed to drink that amount then expire 10 lt of sweat per day and a 10 lt water intake without an appropriate "salt" intake would be almost lethal.
Could be wrong of course
corvus

here is a link to an interesting article on overhydration

http://www.merck.com/mmhe/sec12/ch158/ch158c.html

Overhydration occurs when the body takes in more water than it loses. Overhydration can occur, for example, when athletes drink excessive amounts of water or sports drinks to avoid dehydration, or when people drink much more water than their body needs because of a psychiatric disorder called psychogenic polydipsia. The result is too much water and not enough sodium. Thus, overhydration generally results in low sodium levels in the blood (hyponatremia—see Minerals and Electrolytes: Hyponatremia), which can be dangerous. However, drinking large amounts of water usually does not cause overhydration if the pituitary gland, kidneys, liver, and heart are functioning normally. To exceed the body's ability to excrete water, a young adult with normal kidney function would have to drink more than 6 gallons of water a day on a regular basis.

Overhydration is much more common among people whose kidneys do not excrete urine normally—for example, among people with a disorder of the heart, kidneys, or liver. Overhydration may also result from the inappropriate secretion of antidiuretic hormone

Interestingly, while browsing some journal articles I noticed sportsman (football players, badmington etc) lose about 1.7-2L sweat in a game... now these conditions were typically British weather so I would hate to guess how many litres an unclimatized (perhaps not fully trained) Aussie could lose hiking thru the tropical humidity of the PNG jungle..... so while 10 L does seem like a lot to drink, it could definitely be possible (think of how much some young lads drink on a friday night doing no exercise except opening the can! )

Tony,
I think what I was trying to describe is that these hikers are losing alot of sweat and hence sodium- so by drinking H20 they are replacing fluid lost but not sodium. The body usually maintains a homeostatic balance- but like all balances with the right conditions they can reach the stage where the body cannot adequately compensate. In addition, perhaps the body is actually making itself more hyponatraemic by holding onto water (rather than peeing it out) to protect circulatory volume.
Symptoms of hyponatraemia can also be similar to heat stroke- dizzyness, nause, vomiting, headaches, confusion, muscle cramps- it would be easy to treat incorrectly.
Wow this is getting the brain in gear...

Tony wrote:here is a link to an interesting article on overhydration

http://www.merck.com/mmhe/sec12/ch158/ch158c.html

Overhydration occurs when the body takes in more water than it loses. Overhydration can occur, for example, when athletes drink excessive amounts of water or sports drinks to avoid dehydration, or when people drink much more water than their body needs because of a psychiatric disorder called psychogenic polydipsia. The result is too much water and not enough sodium. Thus, overhydration generally results in low sodium levels in the blood (hyponatremia—see Minerals and Electrolytes: Hyponatremia), which can be dangerous. However, drinking large amounts of water usually does not cause overhydration if the pituitary gland, kidneys, liver, and heart are functioning normally. To exceed the body's ability to excrete water, a young adult with normal kidney function would have to drink more than 6 gallons of water a day on a regular basis.

Overhydration is much more common among people whose kidneys do not excrete urine normally—for example, among people with a disorder of the heart, kidneys, or liver. Overhydration may also result from the inappropriate secretion of antidiuretic hormone

If you do the maths on this equation it all gets a bit to silly as you would need to drink 22.71 lt of water for this to occur so this is a bit of a "Micky Mouse" thread as I said IMHO

Corvus,
Go on an extended hike in hot, humid conditions- drink 10 litres and see if it is Mickey Mouse or not..... (only joking Do Not do this). The link that was put on describes the normal mechanisms, and does not account for the body losing large amounts of sodium through sweating- however in the conditions I was describing and at the exercise levels- I definitely believe it is possible and I imagine the people that have gotten ill/died would probably agree!
It is true that it will probably not happen to you or I (or for that matter most of the people reading this) but it can happen and you never know it may make us all a bit more aware about electrolyte replacement. It is also important to be aware that we all sweat diffferent amounts and also different amounts of sodium so this would also make a difference...
It is a it like hypo or hyperthermia- the body can usually maintain euthermia but eventually the mechanisms that maintain out temperature will get overrun.
Anyway I though it was interesting, you think what you will....

Hi Lizzy,

Lizzy wrote:Tony,
I think what I was trying to describe is that these hikers are losing alot of sweat and hence sodium- so by drinking H20 they are replacing fluid lost but not sodium. The body usually maintains a homeostatic balance- but like all balances with the right conditions they can reach the stage where the body cannot adequately compensate. In addition, perhaps the body is actually making itself more hyponatraemic by holding onto water (rather than peeing it out) to protect circulatory volume.
Symptoms of hyponatraemia can also be similar to heat stroke- dizzyness, nause, vomiting, headaches, confusion, muscle cramps- it would be easy to treat incorrectly.
Wow this is getting the brain in gear...

From my understanding over hydration and Hyponatraemia are closely linked, below is an article about Exercise-associated hyponatraemia (EAH) that appeared in New Scientist Jan 9 2010, it was part of a larger article on exercising and was under the heading of MYTH, 'You need to 'push fluids'.

Tony

'You need to 'push fluids'

Everyone knows the importance of keeping hydrated. Whether it's a water bottle or a sports drink, athletes and gym bunnies are rarely seen without a source of fluid close at hand. Common advice is to deliberately drink beyond what thirst dictates, or "push fluids", to combat dehydration and keep performance up to scratch.

Usually that's a waste of time, and just occasionally it can be fatal. Exercise-associated hyponatraemia (EAH) is a dangerous condition that occurs when people have drunk so much that the concentration of sodium in their blood falls too low. This leads to excess water moving into the tissues of the brain, causing brain swelling. Symptoms include nausea, vomiting and confusion. In rare cases - 12 have been recorded worldwide - the victim has died.

Slower marathon runners, who tend to drink more over the several hours it takes them to complete the course, are one group more likely to develop EAH , and women seem to be more at risk than men.

The condition can even be caused by sports drinks claimed to be “isotonic” –meaning that they contain they contain the same concentration of dissolved substances as normal body fluids – as they tend to contain sugar but very little salt.

Cases of EAH rose in the US in the 1990s. Tim Noakes, director of exercise science and sports medicine unit at the University of Cape Town, South Africa, who was first to descrbe the condition, blames the rise on marketing activities by the makers of sports drinks, which he says promote overdrinking (British Journal os Sports Medicine, vol 40, p567). He also claims that guidelines issued by the American College of Sports Medicine and other bodies have been influenced by sponsorship from the manufacturers of Gatorade, formerly Quaker Oats, now PepsiCo.

Since awareness of EAH has grown, most guidelines now warn athletes not to overdrink. Although some examples of advice to drink “as much as possible” remain, most advice now sets lower and upper limits on how much to drink. Ron Maughan, a physiologist and sports nutrition specialist at Loughborough University in the UK, says blanket guidelines are flawed because people vary in how much they sweat. He recommends that people weigh themselves before and after their exercise to find out how much they sweat, and drink enough to maintain their body weight.

But this is overdoing it, says Noakes. Drinking to satisfy your thirst is all that is needed. “The easiest way to lower your performance is to overdrink, not underdrink.”

All very interesting, but with all these experts giving us their opinion, I haven't read one thing about how to assess hydration, which after all, is the litmus test of 'drinking enough' to stay hydrated without over doing it.

People working on outback mine sites are given a colour card during training to help them assess their hydration by the colour of their piddle. Its a simple test, and the 'user' can easily regulate and learn about their own body's requirements. Anything clear to light straw coloured is fine. If the pee goes darker, drink more. If that's a good enough test for them, its probably good enough for us.

photohiker wrote:All very interesting, but with all these experts giving us their opinion, I haven't read one thing about how to assess hydration, which after all, is the litmus test of 'drinking enough' to stay hydrated without over doing it.

People working on outback mine sites are given a colour card during training to help them assess their hydration by the colour of their piddle. Its a simple test, and the 'user' can easily regulate and learn about their own body's requirements. Anything clear to light straw coloured is fine. If the pee goes darker, drink more. If that's a good enough test for them, its probably good enough for us.

Hi Michael,

That's a very simple and effective tool that can be used by anyone and is even used by elite level athletes (in addition to weighing themselves, before and after exercise) to determine whether they are adequately hydrated. (The only challenge with this method is when the athlete also happens to have a vision impairment but, for every problem, there's always a solution - just get someone else to check!).

Cheers,

JB

Colour test can be flawed by other ingested foods/vitamins - just look at the effect of a high vit B supplement on the colour of urine for example, or phenylketonurics who cannot process phenylalinine effectively.

Elite cyclists in Le Tour and Ironman can lose up to 4.5kg in sweat alone, these guys are burning around 1800kcal an hour so they are ingesting dissolved carbs and electrolytes in bottles of water, along with carbs in bar form and gels. Ambient temps between 5 and 35 degree C, each bottle is around 800ml and they can only carry 2 on the bike, so the domestiques ferry the bottles to the team from the team car. My point is, at this level of competition these guys generally consume about 2-3L during a stage of around 4-6 hours, relying on re-hydration after the race.

I still feel the best way to gauge sweat loss is via weighing oneself where possible. Carbs burnt will slightly affect the measurement, but you're only talking grams depending on the exertion level. You can also roughly check hydration levels (so I'm told) by the colour on the back of your tongue - the amount of white, but I've not read enough on this or experimented to get any finite data.

Adequate baseline hydration can be gauged by hydrating oneself over a period of days with normal duties and exertion (and regular diet and stool passing), then weighing in and averaging the weight over a period of a week or so. This of course needs to be revisited with any change in diet, toilet regularity, sickness or deviation from 'normal'.

Interesting thread as I was bailed up by a concerned friend that I might have been endangering myself after seeing this program. Err Tassie can get hot and muggy but I would bet that Kokoda is a fair bit more so so thanks TV for once again putting the fear of the devil into people, we would be so much safer staying at home and watching TV It never ceases to amaze me that complex issues to do with the body get boiled down to some wonder pills or technique It is clear that people have been dying and suffering ill effects so work is needed and the drink more water message might not be the correct one by itself. Some of the stated level of water consumption have me flabbergasted as I am more likely than most to drink the creek dry but can not remember when walking to have drunk more than three litres in a day but this is Tassie not the tropics so maybe people do. For me the trek would be one long toilet stop at ten litres. Me think people misjudge water in or must have stomach more tolerant than mine.

For a "weekend warrior" comment I was not aware that elite training regime was a prerequisite to retracing our soldiers' footsteps. In fact, many of our soldiers were rushed there poor trained. I think sensible advice and observation by the tour group companies is the fix along with accepting that causalities will happen with any strenuous activity. The trick now is to get that sensible advice, bit like the studies on Everest on altitude is shedding light on issue that excursion involves. I would much favour a holistic approach developed by specialist than snatches of information strung together to give the impression of research. What I have seen appears to be a repeat of "red wine good / alcohol bad" merry-go-round.

Cheers Brett

Well this is my last comment on this topic- all I was trying to do with it was for any interested party to have a think and maybe it might remind people who don't already do it- that it is important to replace electrolytes and that there can be a danger in pushing water in hot/humid conditions where they may sweat buckets and lots of salt with it....
Most of my hikes you simply do not have enough water to drink buckets along the track so I would tend to dehydrate more than fluid overload, but on some trails there is plenty...
Maybe this topic was not of interest to some of you Tasmanians that don't get these condiitons- so don't read it- get back to watching Mickey Mouse!
Ta Ta
Lizzy

Hi Lizzy, thanks for bringing up the topic, it is an interesting topic which I've heard of before, and wondered about how you judge how much to drink. Surprisingly it can get very hot bushwalking here in summer and hydration is an issue. I've been trying to work out what the best thing to drink is, and how much as I often get migraines after a walk. I didn't get a migraine when I walked in Kakadu in the heat though, and we drank quite a lot of (only) water but it would have been nowhere near 10l a day. That's a huge amount, although I suspect that as you said, people out drinking would put that much away at times, be interesting to find out! I now often take a bottle of proper sport rehydration drink, which I drink in 3 - 4 bursts through the day, and a bottle of water to sip on.

Hi all,

Last year I was working in western Qld for my research and in late November/early December there were several days where temps climbed into the mid to high 40s. One particular day I went through 7 litres of water. Most fluid I lost was through perspiration and did not need to go to the toilet much. I mentioned this to our OH&S bloke when I was back at uni and he told me that in future, if I have to drink anymore than the 7 litres I had had, I should stop all work for the day and head back to camp. Our OH&S bloke has a military background and told me they ensure soldiers do not drink too much for the very reason that is dilutes the body’s salts (electrolytes), which concur with what Lizzy said about the lack of replacement of sodium. I think the advice about adding gatoraide might have some merit too as my grandmother’s doctor tells her to drink small volumes of sports drink when she is gardening in the hotter months.

Water from Wikipedia has a lot of info.

Just did a forum search for salt, there is a heap of discussion in quite a number of topics so it's obviously an important topic.

Last month I was out doing field work in the Afar region, +45 degrees, had no trouble downing 6 litres and still having orange wee. That was before lunch.
My father and his workmates used to take salt tablets when they worked at EZ Risdon (as it was then known), noone seems to do that anymore - sodium started getting "bad press" during the '80's, and doesn't seem to have recovered from that.
Twelve deaths in all of medical history someone said? You'd have to be pretty unlikely to die cause of it.
I guess you should listen to your cravings, your body knows when it gets thirsty, and I think most of us have experienced the craving for salty food too. The wee color test is fantastic, we have that at work as well. But if you start drinking alcohol, the diuretic effect results in clear colours even though (or indeed because) your body is actively dehydrating.
Cheers (!)

corvus wrote:Don't know the full details however IMHO 10 liters of water on one walk is a total beat up as there is no way you could expire any way near that amount or pee it out (300 ml average pee) would mean that you would need to pee at least 30 times in one day,so IMHO you would drown with 10 Lt of water intake
corvus.

- that is the whole point your cells would be drowning...

corvus wrote:I also consumed around 6lt of water over a 5 hour period last Summer whilst walking in temperature between 35% and 38% ,I also took glucose tablets and spoonfuls of Staminade ate salty cheese and salami.

wasn't going to say anything else but couldn't resist- so 10 litres of water is a total beat up yet you say you have consumed 6 litres in 5 hours .... so would 10 litres not be possible over an 8-10 hour hike, or perhaps someone could drink more than you....

Medically your kidneys should excrete at least 30mL per hour (less requires interventions / classed as kidney failure) I just supplement the intake with a weak mix of isotonic sports drink powder(causing it to be hypotonic slightly)... not rocket science just put in what your body uses and replace it gradually plus it covers the taste of puritabs or bleachy taste of drops too. 10 litres is possible in a day ( i assume they mean 8 - 10 hours-makes it 1 L / hour ish), and if its hot enough you wont notice the rate of evaporation. look for muscle cramps, fatigue, poor coordination, dry lips and mouth lack of sweat in heat, feeling cold in heat etc... nibble solid food and don't over eat. ... no wonder they were stuffed though.

Lizzy wrote:

corvus wrote:Don't know the full details however IMHO 10 liters of water on one walk is a total beat up as there is no way you could expire any way near that amount or pee it out (300 ml average pee) would mean that you would need to pee at least 30 times in one day,so IMHO you would drown with 10 Lt of water intake
corvus.

- that is the whole point your cells would be drowning...

corvus wrote:I also consumed around 6lt of water over a 5 hour period last Summer whilst walking in temperature between 35% and 38% ,I also took glucose tablets and spoonfuls of Staminade ate salty cheese and salami.

wasn't going to say anything else but couldn't resist- so 10 litres of water is a total beat up yet you say you have consumed 6 litres in 5 hours .... so would 10 litres not be possible over an 8-10 hour hike, or perhaps someone could drink more than you....

Well Lizzy lass,
Nice to know someone is reading my posts however even in my spotty youth I dont think I could have done an 8 to 10 hour walk in conditions that required 10 lt of fluid intake( In a pub, perhaps I even tried it several times) however I was commenting on normal folk in normal conditions not the uber fit and healthy (cannot include those on the Kokoda as all being fit ) my 6lt intake on the instance I mentioned was in exceptional circumstances experienced only once in all my years of walking in Tasmania but I concede a point Lizzy, 1 corvus 0

If you walk for 8 - 10 hours then 10 L / day might only be 1L/Hour... not that much to drink in a tropical environment walking... and with heat and evaporation you might not notive how much you sweat... - just take a isotonic sports drink powder with you and mix it weak in you hydration bladder... watch for cramps, dry lips, and as long as you pee at least 30+ mLs /Hour you have enough goin through your kidneys..... roughly. Too much salt intake will mess you up too though.

Liamy77 wrote:If you walk for 8 - 10 hours then 10 L / day might only be 1L/Hour... not that much to drink in a tropical environment walking... and with heat and evaporation you might not notive how much you sweat... - just take a isotonic sports drink powder with you and mix it weak in you hydration bladder... watch for cramps, dry lips, and as long as you pee at least 30+ mLs /Hour you have enough goin through your kidneys..... roughly. Too much salt intake will mess you up too though.

8 to 10 hours walk with overnight or longer pack for most would be extremely knackering in any conditions never mind the fluid /salt intake dont you think ?? ,most probably for me and I stroll on a regular basis.
However youth will out and good luck to those who take on this challenge and please post regarding your 8 to 10 hour walk in temperatures above 35 % as I am in Tassie and it is a once every blue Moon occurence
corvus

12 hrs at 40degrees on the Eastern Arthurs on NYE.
Day before was a 10 hr day at 30+
14 hrs from Prion beach to Cockle creek in 30+ degrees,

Mind you I did suffer pretty bad on at least one of those days and not so sure i'd be keen to do it again.