Water - How much is too much?

[tanya]

Endurance Athletes Risk Deadly 'Water Intoxication'

Health experts cautioned yesterday that some endurance athletes drink too much water during exercise and are at risk of deadly "water intoxication."

Marathon runners, triathletes and cyclists are familiar with dehydration, caused by not drinking enough. But fewer are aware that too much water can kill.

Water intoxication is formally called exercise-induced hyponatremia (EAH). One recent study found that 13 percent of Boston marathon runners suffered from EAH, though most cases were mild. But since 1985, there have been at least eight documented fatalities from EAH related to long-distance events.

The disorder occurs when endurance exercisers drink more fluid

[stefan]

interesting ...

i've often wondered about the preemptive consumption of water approach. i think camelbacks and the like can lead to rapid/over-consumption for some folks.


while i tend to agree with the idea that there is a window between being thirsty and dehydration, i think that window can be narrowed when one frequently hikes in the desert, especially with scant water sources. that is, it's possible to prolong the onset of pestering thirst to conserve water consumption

[gonzo]

I've run a few ultramarathons (distances greater than 26.2 miles) and hyponatremia is a serious risk at such distances. The general wisdom is to watch your hands - if they're noticeably swollen you're probably consuming too much water. You should back off on the water, and consider taking some sort of electrolyte replacement capsule to even out your sodium levels.

If you have the ability, try weighing yourself every 6-10 miles (many organized ultra races, especially in the 100 mile distance, have scales at the aid stations). If you're weight is up, even a few pounds, you need to reduce your water intake. If you're over 10 lbs heavier, sit down for a 10-15 minutes, urinate, and see if that brings your weight down. Conversely, if you're weight is 10 lbs less than where you started you need to eat and drink more.

There's a lot of good resources out there on hyponatremia. There are some very knowledgeable people on the Ultra Runner mailing list (http://www.ultrunr.com/list.html), and this is an excellent article: http://www.rice.edu/~jenky/sports/salt.html

[tanya]

I got heat exhaust on a recent hike (that's 3 times for me now!) so this last time in Buckskin I drank a bunch! My hands were so swoolen that my knuckles looked bruised and my wrists hurt like crazy!

My poor kidneys kept me stopping all day and late into the night!

I think I over did it a bit then. I did not relate the hands to drinking too much. I was just thinking that for once I drank enough!

[gonzo]

As I understand it if you're hands are swollen, but you're still urinating you're not fully in the danger zone (http://www.youtube.com/watch?v=f0UOZ9NHDsY). The body is still actively trying to correct the sodium and electrolyte imbalances against the amount of water in your system. But, it would be wise to eat a salty snack like peanuts or crackers at that point. (You can also take an electrolyte capsule, such as Succeed S Caps (http://www.succeedscaps.com/main_scaps.html), which claim to replenish the missing electrolytes and sodium).

Keep in mind I'm not a doctor, and any medical advice in my posts should be ignored, or at least verified against a good source.

[tanya]

Then I was certainly not in danger. That part was working all too well! :mrgreen:

[TreeHugger]

One way to determine about how much you need to drink is to weigh yourself before you exercise and then after. The amount of weight you lose is, generally, the amount of fluids you should consume in that amount of time. Drink your usual amount and then adjust as needed. The important thing to remember is that you need to replace the SALT that you are excreting when you sweat. Electrolyte drinks and sodium tablets, or salty snacks are essential for extended exercise. If I'm going to be exercising for an hour or less, water, about a nalgene bottle worth, depending on the heat. Over an hour: gatorade. Over two hours: gatorade and snacks or gel.

[R]

Abby carries one bottle of sports drink and two bottles of water, and finds that switching back and forth does really well with her. I on the other hand find that if I make myself eat something about every hour, even something small, it helps my hydro-balance and keeps me fueled. -R

[derstuka]

If you have the ability, try weighing yourself every 6-10 miles (many organized ultra races, especially in the 100 mile distance, have scales at the aid stations).


Can you actually stop in a marathon to weigh yourself and not be disqualified, or is that just for ultramarathons? Maybe I am thinking about the Olympics or something, where if you stop, you are out.

[gonzo]

If you have the ability, try weighing yourself every 6-10 miles (many organized ultra races, especially in the 100 mile distance, have scales at the aid stations).


Can you actually stop in a marathon to weigh yourself and not be disqualified, or is that just for ultramarathons? Maybe I am thinking about the Olympics or something, where if you stop, you are out.

I've never seen a marathon with health stations, but I've only run four street marathons so I'm not an expert. But, you can certainly stop at a marathon without getting disqualified. Although, if you're a competitive runner (sub 3:40) you'll almost certainly lose if you stop.

[Jaxx]

I like to suck on hard candies while I hike, seems to help me, along with water of course.

[donny h]

If I'm drinking a lot of water, I stick to the 2-1 rule, for every 2 quarts of water drink one quart of sports drink. I use powdered mix on the trail, Gookinaid is better for you than Gatorade.

I also have a packet of Ceralyte in my survival kit so I can treat electrlyte imbalance, water intoxication is only one way of throwing your electrolytes out of wack, there's also giardia, food poisoning, motion sickness, flu, deathly hangovers...