Yikes--hydration

[wabisabi]

Here is an article from this morning's NY Times about over-hydration.

Brain-Dead From Sports Drinks

For years now, we've been hearing about the importance of hydration to avoid heat stroke during prolonged exercise in hot weather. Now, it turns out, too much hydration can kill you.
A study published today in The New England Journal of Medicine should give weekend warriors reason to rethink the wisdom of quaffing vast amounts of water or sports drinks while exercising vigorously - at least if they are engaging in such endurance tests as a marathon. The study found that a marathon runner could dangerously dilute the blood with an overdose of liquids, risking a coma and even death. The problem has also been detected during long military maneuvers, extended bike rides and blistering hikes through the desert.
An article by Gina Kolata in The Times today describes the slow and belated recognition of the problem. A South African expert who has been warning of the dangers for more than two decades told Ms. Kolata that he had not found a single case when an athlete had died from dehydration in a competitive race, but that some people had sickened and died from drinking too much. Typically, an overdose of water dilutes their blood and reduces the concentration of sodium. Water enters the cells, causing them to swell, and engorged brain cells press into the skull; such pressure can lead to confusion, seizures and a loss of vital functions.
All too often, friends, coaches or emergency personnel assume that the problem is dehydration and administer yet more liquid, making the problem worse. The best treatment is a small volume of a concentrated salt solution, given intravenously, to increase blood sodium concentrations. Sports drinks containing electrolytes may not help much as they are mostly liquid themselves.
In the 2002 Boston Marathon, for example, a 28-year-old woman found herself exhausted after running for five hours and gulping sports drinks along the way. Wrongly assuming that she was dehydrated, she chugged down 16 more ounces of a sports drink. She promptly collapsed and was later declared brain-dead. The concentration of salt in her blood was found to be lethally low.
In the study published today, researchers at various Harvard-affiliated institutions tested 488 of the nearly 15,000 runners who completed the 2002 Boston Marathon. They found that 13 percent had blood with abnormally low sodium levels, and that three runners were in danger of dying. It was not the elite runners who were at risk - it was those who had taken four hours or more to finish the race, allowing plenty of time to imbibe excess fluid.
Sports authorities have already issued warnings and tips to avoid excessive drinking, and rescue workers in the Grand Canyon now carry devices to test collapsed hikers for low blood sodium. But the solution is for overly eager endurance runners and hikers to forget the old mantra that they should drink-drink-drink. Too much liquid can be lethal.

[spazzdog]

Pardon the spelling:

Hyper-natremia: too little water, too much salt or combination of both

Hypo-natremia: water intoxication, too much water.

[DeniseGoldberg]

I think that we need to be careful not to let articles like this stop us from drinking.

I read the same article in the Boston Globe this morning, and one of the things that jumped out at me was the quote "They found hyponatremia was most serious in runners who gained substantial weight -- 4½ pounds to 11 pounds -- from drinking lots of water along the route." I try to drink constantly as I ride, and I have weighed myself before & after exercise. I have never gained weight in the interim - I guess my combination of drinking, sweating, and exercising strikes the right balance.

[Bike Goddess]

Ditto for me! Take this article in moderation as everything else we read, right?

[SadieKate]

Actually I know several mtb guides who have had to deal with clients with this problem (like rushing them to the ER from the outback). Naturally, when you are dealing with clients who may not be used to low humidity and high altitude (and of questionable fitness), you encourage them to drink lots. These guides are receiving better training on recognizing the problem. I still think dehydration is the more prevalent problem, but hyponatremia is cropping up here and there.

[alison_in_oh]

This article is all over the internets today! My sweetie used to suffer from some form of mild hyponatremia after long group rides, which we discovered when stoking him up with salty food (ramen noodles!) after such rides staved off his tendency to have low-blood-pressure dizziness and near-fainting.

But personally I don't think I'm at risk! According to http://cptips.com/fluids.htm we should take 4 to 8 oz every 15 minutes. On a hard ride I don't have time to drink, and I end up going through barely 18 oz in 2 hours! I don't guzzle when I get home either, it takes me something like an hour after I'm off the bike to realize I haven't peed and my mouth is like cotton and that when I sip water it tastes like the sweetest elixir.

That site also has great info about treading the line between hydration and hyponatremia, and discusses the relevance of electrolyte replacement and glucose-containing drinks.

[wabisabi]

I agree with most of you--I am more likely to not drink enough, and will pay at the end of the ride with leg and foot cramps if I don't.

It can also be a real problem for me because I have a lot of problem with food additives and allergies, and a lot of the stuff in various sports drinks.

Let this be a cautionary note for all--I have done a lot of sports activities (backcountry skiing, etc.) that caused me to get hurt, or sometimes get a headache, and I would pop a NSAISD or 3 (Ibu., Advil, etc.) The cumulative effect was to really trash my gut, so that the little villi thingies don't work too well, and I can't eat things like wheat, most grains, soy without a resultant, uh, very short transit time through the plumbing. According to the literature, this can show up, often in women, when we are 50 or so, exacerbated by the NSAIDs. Of course, this is an additional cause of dehydration, and the cramps are usually a sign of that. I may have to resort to drugs at some point, but do not want to compromise the ability to ride.

[fixedgeargirl]

I read the same article in the Boston Globe this morning, and one of the things that jumped out at me was the quote "They found hyponatremia was most serious in runners who gained substantial weight -- 4½ pounds to 11 pounds -- from drinking lots of water along the route."

4.5 to 11 pounds!?! That's .5-1.5 GALLONS of water! These people obviously had a lot of time to drink!

[Trek420]

fixedgeargirl " 4.5 to 11 pounds!?! That's .5-1.5 GALLONS of water! These people obviously had a lot of time to drink!"

can we talk? they don't pee, i've never seen rest stops with porta potties on marathons .... anyone? runners, a little help here? I don't run so really don't know.

On long distance rides we have rest stops and my motto is "you can't stay hydrated if there's nowhere for it to go" so I never miss a chance. If it's hot I'll stop on the way into the stop and on the way out.

One day on the AIDS ride last year I was thirsty but 15 miles to the next rest stop. Then I saw "look, doughnut shop!", so i stopped, asked to use their restroom, bought doughnuts, had one doughnut, passed out the rest one by one to passing riders till done, then hopped back on the bike.

[maggieH]

My son, who's done Boston a few times, commented snidely:

Yeah, this is sort of old news, that's making a revival as part of the
build up to the Boston Marathon on Monday. What's happening is that
untrained people are 'doing' a marathon in 5 or 6 hours, which isn't
even fast enough to break a sweat, but they're still drinking four or
five cups of gatorade at each water table. This isn't an issue for
people who treat it as an athletic event, rather than an ambulatory buffet.

[MomOnBike]

When I first read this article I diagnosed a bad case of "If a little does a little good, a lot will do a lot of good" syndrome. My family has a tendency to this, so I'm in a position to speak (Dad burned a house down once that way - don't ask).

We all need hydration, but moderation and monitoring is what we all need to practice. Listen to your body.