Forum Index » Philosophy & Technique » The Hype of Dehydration and Heatstroke


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Craig W.
(xnomanx) - F - M
The Hype of Dehydration and Heatstroke on 04/08/2013 15:03:36 MDT Print View

From The Science of Sport, one of my favorite sites.
http://www.sportsscientists.com/2013/01/dangerous-exercise-hype-of-dehydration.html

Interesting read, especially in the context of backpacking, which would typically be categorized as not strenuous (sorry, as hard as I know it can feel to some, it's not the same as racing a time trial or other high intensity pursuits).

The article raises the issue of underlying causes as well as personal perception; being made very uncomfortable by thirst or heat while simultaneously being in no actual physical danger.

It also makes me wonder about how effectively we have all been marketed to be drink and supplement companies.

I've always thought that overly complex hydration and nutrition strategies during average backpacking pursuits seemed a little silly in the face of athletes that can knock down 4:45 miles for 26 straight, lose 5kg of bodyweight in the process, not take a single sip or bite, and recover just fine.

BJ Clark
(bj.clark) - MLife

Locale: Colorado
Waterlogged on 04/08/2013 16:26:34 MDT Print View

Waterlogged: The Serious Problem of Overhydration in Endurance Sports
Timothy Noakes

The above is a pretty detailed look at the issue of hyponatremia or over hydration. While dehydration can be an issue, a lot of what we were taught as coaches and athletes may not be particularly accurate. It's a long book and extremely detailed, but Noakes is one of the premier exercise physiologists in the running community. Needless to say, the Gatorade sports science guys are not happy with his research.

Edited by bj.clark on 04/08/2013 16:27:11 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Waterlogged on 04/08/2013 17:29:04 MDT Print View

> Needless to say, the Gatorade sports science guys are not happy with his research.

There are NO 'Gatorade sports science guys'. None. Contradiction in terms.
They are mainly marketing spin doctors with funny hats on.

Cheers

BJ Clark
(bj.clark) - MLife

Locale: Colorado
Re: Re: Waterlogged on 04/08/2013 17:33:17 MDT Print View

Roger,
I stand corrected and humbly so! And I agree.
BJ

Doug I.
(idester) - MLife

Locale: MidAtlantic
Re: Re: Waterlogged on 04/08/2013 17:58:46 MDT Print View

"There are NO 'Gatorade sports science guys'. None"

That's a bit harsh. Perhaps not now, but it was developed by researchers.

Edited by idester on 04/08/2013 18:51:54 MDT.

Ken Thompson
(kthompson) - MLife
Re: Waterlogged on 04/08/2013 18:12:20 MDT Print View

Go Gators!

I still like the lemon lime.

Though is has certainly changed since it first came out.

Heatstroke sucks. I don't recommend it.

Thanks for the link.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Waterlogged on 04/08/2013 18:16:13 MDT Print View

They had me drink Gatorade the night before colonoscopy

I do not like Gatorade

spelt !
(spelt) - F

Locale: Midwest
Re: Re: Re: Waterlogged on 04/08/2013 18:47:40 MDT Print View

Me neither, Jerry.

Todd Taylor
(texasbb) - F

Locale: Pacific Northwest
Re: Re: Re: Waterlogged on 04/08/2013 19:17:37 MDT Print View

"They had me drink Gatorade the night before colonoscopy

I do not like Gatorade"

Not anymore, I guess! :-)

On the other hand, I'd have given my eye teeth for Gatorade instead of the evil potion they made me drink.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: Re: Re: Waterlogged on 04/08/2013 19:23:16 MDT Print View

"On the other hand, I'd have given my eye teeth for Gatorade instead of the evil potion they made me drink."

That they produce the same result makes one wonder about Gatorade. ;0)

Franco Darioli
(Franco) - M

Locale: Melbourne
The Hype of Dehydration and Heatstroke on 04/09/2013 00:29:06 MDT Print View

I still see the idea that hikers need to continually sip from their water bladder a bit odd but if it makes them happy....

Nelson Sherry
(nsherry61)

Locale: Mid-Willamette Valley
Re: The Hype of Dehydration and Heatstroke on 04/09/2013 11:53:59 MDT Print View

Okay, I can't resist this one. . .
1) Marathon runners don't run marathons without drinking anything. They just don't drink nearly as much as they sweat out.
2) The linked article is about incorrectly attributing sudden death in sporting events to dehydration or heat stroke, not any suggestion that rehydration drinks are less than claimed.
3) I agree with the general direction of this thread that we, as a culture, are over excited about hydration and food chemistry in lower intensity, non-competitive sports.
4) For low intensity exercise in warm weather, gatorade provides people with a nice sugar drink that includes some electrolytes. Both sugar and electrolytes are helpful in keeping one going during exercise on a hot day. What's wrong with that.

Of course, from the standpoint of elite endurance performance, Gatorade is lousy because it isn't the best balance electrolyte mix and it is too concentrated, sugar based, carbohydrates that tends to bloat the stomach, slow digestion and cause vomiting. However, diluted Gatorade actually works pretty well for re-hydration, although there is plenty of better product out there. My favorite re-hydration strategy for lower intensity exercise, like backpacking, is to drink water and eat a balanced diet of various snacks that have some salt in them. Admittedly, during hot weather, some salts added to my water or taken as tablets can be helpful.

HK Newman
(hknewman) - MLife

Locale: Western US
Re: The Hype of Dehydration and Heatstroke on 04/09/2013 12:47:18 MDT Print View

In my experience, a continuous stream of dehydration, heat cramp, heat exhaustion, and heatstroke victims probably keeps the preventative tips in the first aid books (civilian and military). Even "ultra-fit" can succumb since they are used to toughing it out (remember that competitive runner who died in the Grand Canyon a couple years back?).

Handling medical evacs was one of my deployment assignments so during the summer train-up one afternoon, I had a string of Medevac choppers waiting to pick up heat injuries (all ages) out of the field for these problems - they were from another southern state no less, so acclimation only goes so far. A couple of the older ones were never the same health-wise and didn't deploy. In warm to hot weather, dehydration is nothing to mess with (of course, sometimes you just get caught short on water).

ed: gram

Edited by hknewman on 04/09/2013 12:52:51 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: The Hype of Dehydration and Heatstroke on 04/09/2013 13:18:36 MDT Print View

"However, diluted Gatorade actually works pretty well for re-hydration, although there is plenty of better product out there."

For decades now I have used diluted Gatorade on warm backpacking days. Sometimes it is 50% strength and sometimes only 33% strength. The powder probably is not the very best product on the market, but it is cheap, effective, and readily available. I tend toward a potassium deficiency, so Gatorade takes care of that. Alternatively, I could carry along a bushel basket of tomatoes or something. I think I will stick with the Gatorade powder.

--B.G.--

Larry De La Briandais
(Hitech) - F

Locale: SF Bay Area
Heat stroke on 04/09/2013 16:25:39 MDT Print View

Having been very near heat stroke myself (not while hiking) it is nasty business that I don't want to repeat. I will error on the side of drinking to much.

I have also seen a young lady on the verge of heat stroke at the top of Nevada Falls in Yosemite. She had stopped sweating and couldn't lift her head without sever dizziness. She had drank only one liter of water on the climb from the valley to half dome and back. I think it is 17 miles round trip and she was 12 miles or so into it. While I can't say that she would have died from it had she not drank (I filtered water for her group) she easily could have from the fall had she attempted to continue. I don't think she would have recovered before dark without intervention.

While hiking the "secondary problems" can become a deadly problem. And if you can push though the initial symptoms, once you near heat stroke you don't feel bad anymore. The confusion alone is dangerous.

All that said, yeah, staying hydrated is over hyped. You don't need to have clear urine. I hate hydration bladders, a simple water bottle works great for me.

Edited by Hitech on 04/09/2013 16:40:06 MDT.

just Justin Whitson
(ArcturusBear) - M
Re: Re: Re: The Hype of Dehydration and Heatstroke on 04/09/2013 16:38:14 MDT Print View

Bah humbug on Gatorade, i like Coconut water with a bit of salt, or Lemon powder mixed with water and a bit of salt and sucanat.

Paul McLaughlin
(paul) - MLife
Re: The Hype of Dehydration and Heatstroke on 04/09/2013 19:52:04 MDT Print View

Comparing elite marathon runners to backpackers is not of much use. Those guys take about 2 1/4 hours to finish. Yes, they are doing something more intense, but it's very different. My general rule of thumb is that no matter how hard I'm working, if it's 2 hours I can drink before and after and all is fine.

A much better comparison is a full days work on a hot day on a construction site. I've done a lot of that. 8 hours in the heat swinging a hammer and hauling lumber around. And I've watched guys who were not drinking enough get very close to collapse. When you see a guy turning gray and getting wobbly, it makes an impression. So I drink plenty. And It's pretty clear that I'm not drinking too much, since on a hot day I'll drink 5 or 6 liters and still only pee maybe once. Of course, everyone is different. I sweat quite a bit when I'm active, so I need to drink quite a bit to replace that. You have to know your body to know what works for you in various different conditions.

A typical backpacking trip is not as intense as that for me, since it's not often 100 degrees in the mountains. So I would be drinking less than that when I'm hiking - although for the first couple days at altitude I'll drink a little more, as it helps with acclimatization.

The easy indicator is what my urologist told me after I had a kidney stone - you should be peeing every 2-3 hours during the day. If you need to go more often than that, you're drinking more than you need. If you go 6 hours without taking a leak, you ought to drink more.

Craig W.
(xnomanx) - F - M
Re: Re: The Hype of Dehydration and Heatstroke on 04/09/2013 20:15:10 MDT Print View

I'm not sure how many people commenting here actually read the article which got me thinking about this, but here are a few points I found interesting. I see no reason why the underlying ideas behind them couldn't also apply to backpacking, though perhaps on a different time scale.
_____________________________________________________

"Similarly, there is no link between fluid loss and heatstroke. Human beings can safely lose big volumes of fluid without their body temperature shooting through the roof. Typically, in a marathon on a reasonably warm day, we lose about 2 to 3 L of fluid over many hours. Faster runners lose more - Haile Gebrselassie is reported to have finished his Berlin World Record 5kg lighter than at the start."

"Heatstroke is a viable candidate for the tragic deaths that sometimes happen, but it's a grossly overstated risk and those who diagnose any athlete's collapse or medical condition on a hot day as 'heatstroke' are also taking a lazy and possibly very wrong option. The reality is that heatstroke is a pretty complex phenomenon, and is likely to involve some kind of pathology. Once again, I'd draw attention to the difference between the perception of being hot and actually getting to the kind of dangerous temperatures that characterize heatstroke. We're not talking about feeling hot, uncomfortable and slowing down or stopping here."

"...But recreational athletes don't produce enough heat to develop heatstroke through normal muscle activity. Therefore, we look at alternative theories - either these individuals are failing to lose heat, or they produced excessive heat from unnatural means." (I personally wonder how much obesity and/or poor cardio are at work here creating "unnatural means").

"... So the key points from those case studies - there are 18 documented cases, I've only discussed three - is that the athletes who suffer REAL heatstroke most often are not exercising very hard, they're not in impossibly hot conditions, and they show 'abnormal' heat gain even after they've finished exercise, sitting out of the heat (in a bucket of ice, in one case). Clearly, there's something else going on, and heatstroke does not happen just because we run hard on a hot day."

Todd Taylor
(texasbb) - F

Locale: Pacific Northwest
Re: Re: The Hype of Dehydration and Heatstroke on 04/09/2013 20:24:19 MDT Print View

Good comments, Paul. I think very few of the things one learns from running marathons apply to hiking. I always tell backpacking beginners:

It's a trek, not a marathon.

That has implications well beyond hydration. Nutrition, for example: forget those silly gel packs--you need real food to hike 10 hrs/day for a week. And playing through the pain: you can't go home and take a week to recover--you've got to get up in the morning and go again, and the next morning, and the next. If you hit the wall, you don't get to fall out and hitch-hike to the finish line; you must get to a campable spot tonight.

All those things imply sustainable effort and steady intake of food and water. Trickle the calories and water in. Snack often to keep electrolytes up. Etc.

Craig W.
(xnomanx) - F - M
Re: Re: Re: The Hype of Dehydration and Heatstroke on 04/09/2013 20:34:23 MDT Print View

"...forget those silly gel packs--you need real food to hike 10 hrs/day for a week."

Explain that to Greg "Malto" Gressel.

_______________________

I think most people in this thread are mistaking heat exhaustion for heat stroke.
Yes, heat exhaustion brings you to a quick halt and makes you feel like you are going to collapse and die...except you don't die or have to be hospitalized. Not the case with heat stroke.

Edited by xnomanx on 04/09/2013 20:35:34 MDT.