I don't know why, but they email me every week or something

Interesting article:

http://www.outsideonline.com/fitness/The-Top-Sports-Science-Stories-of-2012-A-Bible-on-Overhydration.html

“The science of hydration is utterly bogus,” he said in a 2012 TEDx Talk. “There is no science to it. It was dreamed up by marketers to sell product.”

They discussed whether you should just drink when you're thirsty or when you lose, like 2% of body weight

>> Since 1981, he’s documented roughly 1,600 cases, 12 of them deaths, from hyponatremia in the medical literature.

Did he also collect evidence for that time period of cases of dehydration and associated deaths?

I posted a link to this book several months ago.

Waterlogged: The Serious Problem of Overhydration in Endurance Sports

http://www.amazon.com/Waterlogged-Serious-Problem-Overhydration-Endurance/dp/145042497X/ref=sr_1_1?ie=UTF8&qid=1357676533&sr=8-1&keywords=overhydration

It will change your mind about how much you need to drink. The book is so well researched and documented your heard will hurt from digesting the facts. One main point is that the body's mechanism for demanding water is so strong that if your body needs water you will think of nothing else.

And yes, he goes back researching historical Marathon records and finds no deaths from under hydration. Marathoners from the inception of the sport were taught not to drink as it was believed to hurt performance.

Obviously, you want to drink enough to avoid dieing from dehydration

I think that if my urine is very yellow, I should drink more water. If it's pale yellow I'm okay. If it's warm and I'm sweating a lot, I try to get ahead of this a little and drink more even if it's fairly pale yellow at the moment.

A test was carried out with soldiers (poor beggars). They were marched in the desert till they dropped, with no water supplies. Then they were given water. Time to full recovery was measured.
Result: about 15 minutes was needed, to full recovery. Just 15 minutes!
But over-hydration can kill.
Great marketing spin by the bottle and drink vendors.

Cheers

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/65531

"But over-hydration can kill."

+1

But so can under-hydration. I can think of 3 cases off the top of my head , one of which was me, where dehydration was very nearly fatal. All occurred in hot weather race conditions. One was a world class runner, Alberto Salazar, at the Falmouth 12K race back in the early 80's; one was a national class cyclo-cross competitor, Joe Ryan, who was also an awesome hill runner, at the 1981 Dipsea Race in Marin County, CA; then there was me at a trail marathon outside Lone Pine, CA in 1993. I was in pretty fair shape at the time, but race temps were in the 90's during the last 1/3 of the race. The folks at the emergency ward put 2 liters of electrolyte solution in me, and told me I was lucky I had strong kidneys. I'm sure these cases are not unique. My point is to not wait until you are thirsty to drink, especially in hot weather, nor to overdo it, especially if you are not adding electrolytes to your water.

Lack of electrolytes is. It is the water without the electrolytes that is deadly. This was a problem at a marathon I ran where they ran out of sports drink and only had water. I think this also happened at the Chicago marathon some years back.

The author shoots down the electrolyte myth as well. Any distance athlete should read the book. He starts out by hypothesizing that man's inability to go without water (due to hairlessness, upright posture and incredible control of electrolyte levels) were some of the evolutionary traits that led to the development of a large brain. The author contends that the Gatorade Sports Science Foundation invented the whole myth of under-hydration and electrolyte shortage.

BTW, the problem with assuming that people are dehydrated after athletic performance is the reason that people die during rehydration. He explains in great detail how not to be confused.

Read the book, at the very least I think anyone with an inquisitive, scientific mind will find it interesting. Don't purchase the E version as the charts and footnotes are not formatted properly.

Hyponatremia (low blood sodium) is a real clinical condition that kills some marathoners and others. When Noakes mentions electrolyte myths, he is likely talking about the sports drink market. But, Noakes' evolution hypothesis is nutty.

Edited by jshann on 01/08/2013 20:11:43 MST.

"Hyponatremia (low blood sodium) is a real clinical condition that kills some marathoners and others. "

Basically that is what drove him to write the book in the first place. The woman who he knew that died running her first marathon because she had the hormone that makes one much more susceptible to hyponatremia.

This is one of the biggest areas of research right now in the ultra endurance world. Our current knowledge base is hampered by limited studies, very small sample sizes, no good pre-race measures of the athletes' blood and kidney function, and a focus entirely on sodium levels and no other metabolites or electrolytes.

The problem really developed with the broadening of endurance events to include very slow participants. If it takes you 6 hours to complete a marathon, and you are told to drink 8 oz of water every 20 minutes...goodness gracious that's a lot of water!! Then more people started doing ironmans, and ultra marathons...and were told to drink all this liquid every 10-20 minutes...it's crazy actually.

Anyway, the current best practice guideline is to drink when you are thirsty and not to worry otherwise. This is a highly relevant abstract from a piece in the journal Wilderness Environmental Medicine:

Wilderness Environ Med, 2009 vol. 20(2) pp. 139-43

Exercise-associated hyponatremia: overzealous fluid consumption.

Rogers, IR; Hew-Butler, T

Exercise-associated hyponatremia is hyponatremia occurring during or up to 24 hours after prolonged exertion. In its more severe form, it manifests as cerebral and pulmonary edema. There have now been multiple reports of its occurring in a wilderness setting. It can now be considered the most important medical problem of endurance exercise. The Second International Exercise-Associated Hyponatremia Consensus Conference gives an up-to-date account of the nature and management of this disease. This article reviews key information from this conference and its statement. There is clear evidence that the primary cause of exercise-associated hyponatremia is fluid consumption in excess of that required to replace insensible losses. This is usually further complicated by the presence of inappropriate arginine vasopressin secretion, which decreases the ability to renally excrete the excess fluid consumed. Women, those of low body weight, and those taking nonsteroidal anti-inflammatory drugs are particularly at risk. When able to be biochemically diagnosed, severe exercise-associated hyponatremia is treated with hypertonic saline. In a wilderness setting, the key preventative intervention is moderate fluid consumption based on perceived need ("ad libitum") and not on a rigid rule. (Editor's Note: This paper was written at my request in an effort to increase awareness of this important clinical entity among members of the wilderness community, many of whom are involved in activities that place them at risk of its development. I thank the authors for their diligent efforts.)

PMID: 19594207
URL - http://www.ncbi.nlm.nih.gov/pubmed/19594207?dopt=Citation

They mainly talk about long distance running

What about backpacking and hiking?

A lot of people have packs with hydration bladders and hoses coming out that allows them to hydrate any time they want

Is there any reason to do this or are you just as well off drinking once an hour (or whatever) when you stop for a rest and take your pack off?

I've seen numerous heat casualties and other calamities related to dehydration; mostly heat exhaustion but a couple were heat stroke. None of them died but water resupply was easy and we had the luxury of calling a medevac if it got too bad (never had to).

I know of two fatalities from over hydration(both from SFAS). It was originally diagnosed as hydro toxicity but many feel that it was more along the lines of hyponatremia/kalemia.

Best heat casualty/hydration lecture I was ever given was from a Grand Canyon SAR. A common myth that she busted: Most people are taught that if you are still sweating then you are not in heat stroke yet. She assured us that this was bogus and that she medevac’d countless people who were in heat stroke who were blue and sweating.

The myth began in the OR of all places. Apparently there are some anesthetic drugs with thermo genic properties. The patient's temperature would rise as a reaction to the medication and would go into heat stroke. The physicians observed the patient profusely sweat and then transition to pink dry skin when they reached heat stroke. An assumption was made that this would be the case in all cases.

She placed an emphasis on pushing electrolytes. They would find people laid out on the Grand Canyon trails, rehydrate them, and then see them drop a mile later. They learned that while they were replacing the fluids, they weren’t replacing the electrolytes. Once they started feeding the hikers Wal-Mart special nuclear orange peanut butter crackers, they found a much better recovery rate of the hikers.

I don't have a peer reviewed article to back up her thesis but her credentials were sufficient to convince me. I've found that eating balanced meals is normally sufficient (which can be difficult in the back 40) and I'll take electrolyte supplements when I'm in a really hot/humid environment or a balanced diet is not assured. The two guys who died during SFAS were drinking obscene amounts of water. One report said upwards of five gallons per day.

** added note: I'm not implying that heat casualties are not serious. Just that I haven't experienced one which resulted in a fatality.

Edited by IDBLOOM on 01/10/2013 07:21:48 MST.

http://www.wemjournal.org/article/S1080-6032(09)70110-3/fulltext

http://www.wemjournal.org/article/S1080-6032(12)00087-7/abstract

http://www.wemjournal.org/article/S1080-6032(08)70148-0/fulltext

http://www.overhydration.org/downloads/EAH_Statement_2008.pdf

Edited by jshann on 01/09/2013 21:25:20 MST.

My experience is from the Infantry (hiking basically but in a sucky way) and later EMS/WFR; all of my water was from canteens. My experience has been that it's better to sip than chug. It's also better to chug than not drink enough. I use a platy but I'm thinking of ditching it for something lighter. I'm looking at the ULA Ohm 2.0; I like how the side pockets are laid out and that I have an option to carry the bottles on my shoulder straps. I figure will be able to drink nearly as often as I do with the platy.

Edited by IDBLOOM on 01/09/2013 22:41:09 MST.

I know I am starting to sound like a broken record but the book is only $15 at Amazon. Jennifer I'll bet that after you read the book you will change your mind about the "state of the research" The Doctor that wrote the book is no flake looking for easy money. He spent his entire career trying to get the truth out. He has faced seemingly insurmountable odds trying to overcome goliath while watching athletes die from being administered fluids that were actually killing them. There are studies for over half a century that spell out the facts. The book started out to be over 1200 pages and the editor made Noakes cut it down to 400+ pages.

By the way, I don't think his take on human evolution is any more crazy than anyone else's theory. It makes and interesting lead in to his book.


My take is that high mileage backpackers are indeed endurance athletes. My wife and I stopped electrolyte supplementation and drink so little water during a hike we carry most of it home. If your body is thirsty Noakes said you will be able to think of nothing else. For instance, he said if a Marathoner was on the way to an Olympic Gold medal and his or her body was in need of water they would ver off course and not care about the gold medal. Their only thought would be about the nearest water spigot.

Bottles on shoulder strap will balance some of the load forward which could be good

But carrying lots of water is unnecesary. One pint is plenty unless it's really warm and you sweat a lot and might get heat stroke or whatever. And assuming you know there's a water source every 5 hours or so. Most people feel more comfortable carrying a quart which is only one extra pound.

But REI sells hydration reservoirs that are 100 ounces - that's 6 pints = 6 pounds. That seems unnecesary. Product of the hydration myth that Dave and Jennifer are talking about.

Hi Jenifer

> This is one of the biggest areas of research right now in the ultra endurance world.
Well, then the 'ultra endurance world' is a wee bit behind the times. Go and read Noakes, and take him very seriously.

A bit too much not-invented-here I suspect.

Cheers

Almost everything in life should be done in moderation. Too much or too little is generally bad.

Since I have been hiking in deserts for 35 years, I have learned a few things -- as it relates to my body.

There first thing I learned, during my first year was that you sweat a lot of salts in the heat (or whatever every scientific name you wish to give salt). Anyway the first summer I got very sick and dizzy one afternoon. I had been drinking enough water. So I sat down and rested and ate a bunch of Fritos. Quickly I felt much, much better. I later started taking salt tablets when hiking or working in the summer heat of the desert, but they upset my stomach. So I eat salty snacks when hiking in the heat. Don't force down a lot -- my body seems to know when enough is enough. Just a handful of salted nuts, chips, etc.

I drink water only when I feel thirsty, and not a lot. Just enough that I quench my thirst. Never try to over hydrate. Usually I stop about once an hour and drink then. And in the heat; I stop. If the temps are above 100F, I may drink a little every 30 minutes if I am thirsty.

Also different people need different amounts of water. When Craig Wisner and I hike in the desert he needs almost twice as much water. I guess it is an acclimation thing for me, since I have lived in the desert for the past 35 years.

Also, every year people die from heat stroke when hiking in my part of the world. Usually it is on a day hike and death occurs in 6-8 hours after the start of the hike. The hikers always run out of water. Doesn't take long. So unless you are 100% sure of a desert water source -- carry extra!!