April 15, 2005 at 12:57 am #2410
A study published today in the New England Journal of Medicine is sure to bring the hyponatremia paranoia back out to the forefront, just in time for Boston and London.
Physicians at the Children’s Hospital of Boston Department of Medicine studied 488 participants of the 2002 Boston Marathon and found that 13% showed signs of hyponatremia following the race. This sounds like a serious issue, doesn’t it?
Well, the thing is the common factor is that these individuals on average drank 3 liters (just over 3 quarts) of fluids while on the course. They actually drank enough to gain weight during the marathon, as gaining weight was considered to be the most significant risk factor for hyponatremia. What does this tell us? Seems pretty obvious to me, don’t stop at the aid stations and consider them to be liquid buffets. If you’re drinking 3/4 of a gallon of fluids while out there, you might be overdoing it.
April 15, 2005 at 3:51 pm #18320
People should really weigh themselves before and after long runs to see what kind of water loss they experience – personally – so that they drink the appropriate amount of liquids for them. Not some phony guidline like X onces every so manny miles/minutes.
The wetter your shirt is at the end of a run the more your fluids your body loses – also and most importantly do not drink only water during the race – you need so little sodium and potasium in your system that it is easy to avoid Hyponatremia by getting a hit or two of a sports drink.
April 15, 2005 at 5:26 pm #18321
isn’t the problem that your kidneys do not process water at the same rate so if you lost 10 lbs during a workout (that your body was storing) so you drink 10 lbs of water, but your kidneys can only process part of that… I don’t think it is so simple.
April 15, 2005 at 5:56 pm #18322
Ed, actually, the one interesting thing that came from this study was that there was no correlation found between hyponatremia risk and the type of fluid one was drinking. In other words, those who drank nothing but sports drink were just as likely to develop hyponatremia as those who drank nothing but water.
Guest, from what I’ve read, this risk doesn’t have to do with your kidneys. Hyponatremia is actually an electrolyte imbalance issue more than an overhydration issue. The problem is that you sweat out water and sodium. When you ingest too much water and not enough sodium, your sodium levels get too low in your blood, which creates issues as sodium is an essential mineral. This is why it was believed that using a sports drink instead of water would at least reduce the hyponatremia risk and it’s why I wonder whether taking salt tablets, which I see some people doing in marathons, would make a difference. Of course, the fact that sports drink vs. water didn’t make a difference, along with simply understanding how complex the human body is, points me in the direction of agreeing that there are things going on that we don’t yet know about. However, I still say that this is a fringe issue that can be mostly controlled by not trying to drink a gallon of water while out running and that the paranoia surrounding it is blown out of proportion.
April 15, 2005 at 6:56 pm #18323
The article in the New York Times said that drinking sports drink would not help. They said that your body can not process the water so it goes into your blood stream and ends up affecting your brain…
“Hyponatremia is entirely preventable, Dr. Adner and others said. During intense exercise the kidneys cannot excrete excess water. As people keep drinking, the extra water moves into their cells, including brain cells. The engorged brain cells, with no room to expand, press against the skull and can compress the brain stem, which controls vital functions like breathing. The result can be fatal.”
it does say to do the weighing thing though…
April 15, 2005 at 7:51 pm #18324
Thanks for the clarification. I was always told before that the hyponatremia danger was in electrolyte imbalances. I didn’t realize it was excess water. In that case, it seems like it shouldn’t be too difficult to figure out. That also clearly shows why sports drinks would not help the situation.
April 15, 2005 at 8:22 pm #18325
I get headaches after I run and I went to a sports doctor…even had an MRI. Turns out, I get exercise-induced migraines. They suck. I have tried a lot of things to get rid of them…Hydrate, make sure I’m not too hydrated, I’ve taken Riboflavin (supposed to lessen effects of migraines) and even sodium tablets. Nothing seems to work. Have any of you had this??
April 20, 2005 at 1:08 pm #18326
I had always believed that it was electrolytes as well – hence my comment about electrolyte drinks. If it is a simple case of too much fluid in too little time for the kidneys to adequately screen and process – that is another story all in itself.
It would be gross to do this but to measure the amount of expelled liquid compared to the amount that you drank would provide a measure of the process rate that your kidneys have. This to me would be a better measure than weighing yourself.
April 20, 2005 at 2:09 pm #18327
one thing I had noticed with a couple of my marathons was a serious swelling in my hands… I already know I have an issue with this, never wear rings overnight, had to have one cut off my hand once… I think Ryan is right in thinking this is a ‘fringe’ issue… I think most of the cases have been with women running rather slowly and therefore longer than say 4 hours (not sure, but that’s what I remember)…
for myself it’s become a delicate balance, as everything is, to get enough fluid but not too much… I used to carry my own gatorade since I ran a few marathons where only Ulitma was offered & that upset my stomach… this last one I did not carry extra as they offered Gatorade, but also didn’t drink as much since I was out of practice with those little cups and ran through the aid station on my way to a new PR… results was no bathroom stops, slight dehydration(luckily the weather was cool) but no swelling of the hands…
on the exercide enduced migraine issue, I ‘ve had those and found that insufficient fluid to usually be the root of the problem… so I have to be careful to drink enough, but not too much… and if I get the headache I suck down ibuprofen with gatorade and ice the back of my neck & forehead… sometimes that even helps…
I’m sure that everyone has to find the balance that works for them, and just when you get it figured out something will change, you’ll get older or in better shape (or worse)… the race situation may bring out the worst cases since so many people are trying the marathon without as much history in the sport as runners in previous times… the excitement from the day and the knowledge that you may only get one or two chances to marathon in a year make other people push beyond reason…
while this is no joking matter I know my husband would chuckle to know that running can impair your brain function, he as well as most of my relatives think that my brain is already impaired…
April 20, 2005 at 3:31 pm #18328Ed 1 wrote:It would be gross to do this but to measure the amount of expelled liquid compared to the amount that you drank would provide a measure of the process rate that your kidneys have. This to me would be a better measure than weighing yourself.
Actually, weighing yourself works quite well because almost all weight loss and certainly weight gain experienced during a marathon can be attributed to flud loss or gain. Fat does not weigh much per calorie (about 1 gram per 9 calories) and the reason glycogen weighs more per calorie (about 4 grams per calorie) is because of the amount of water stored with it.r-at-work wrote:I think most of the cases have been with women running rather slowly and therefore longer than say 4 hours (not sure, but that’s what I remember)…
If I remember correctly, the study stated that the average finish time for a hyponatremia sufferer was over 5 hours. Even further, many of the 5+ hour runners were fine. Those who were not fine were those who drank so much on the course that they gained weight. If you’re drinking normally and not trying to force more than you need down, what are the chances that you will gain weight while running a marathon?
April 20, 2005 at 5:35 pm #18329
experience… I wonder how many of those who succumb to hyponatremia have trained for more than a year… when you say “drink normally” it makes me think that I don’t really do anything “normally” when it comes to longer runs… I mean I wouldn’t normally eat gels or even drink gatorade… but I’ll bet you are thinking “as you normally would on your long training runs” and I’m thinking many of those 5+ hour runners have not done enough of those long runs to know what is normal, or normal for them on long runs…
I guess even though I’m part of the running-boom-of-the-masses I did have 7 years of casual running before I even thought of trying a marathon… in fact the week I sent my entry in for my first marathon I distinctly remember talking to a neightbor who had joined the TNT fund raiser, had never run before, trainined for 4 months ended up in the ER and was adamant that she would never run again… didn’t make any sense then, still doesn’t…
ever hear of any cases in races of less than marathon length?
April 28, 2005 at 12:42 pm #18330
I know there is some gray area with the information posted in this thread. Your information about electrolyte imbalances is still very much on target. I am not knowledgeable enough to delineate the study posted from the two other posters comments stating that they always believed it was not strictly water, but electrolytes that was at play, but I can state with a high lvl of certainty that you are correct, but that the kidneys is a second factor. I have strong suspicion this had to do with the time frame. Over a longer time frame electrolyte imbalances are more likely to occur because of the greater quantity of fluid involved.
I hope that helps.
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