Posted on 07/20/2006 8:58:32 AM PDT by presidio9
Arrowhead is L.A. tap water that is filtered and then has the minerals added back in.
Don't get the idea that I believe that Arrowhead Mountain Springs water comes from Lake Arrowhead (although my tap water comes from there). I just use that as an example and it's usually on sale at the local market. The original Arrowhead springs water comes from springs in the foothills of San Bernardino, below the rock formation that gives the Lake its name.
Americans are in danger of becoming over-hydrated;
GSSI: What are the clinical symptoms of hyponatremia?
Hiller : Clinical signs of hyponatremia include confusion, malaise, weakness, cramping, nausea, vomiting, seizures, stupor, coma, and death. Flat affect and hyperreflexia are generally noted upon physical examination.
Nadel : In general, those symptoms consistent with an impairment of brain function are indicative of severe hyponatremia. Mild hyponatremia (plasma sodium concentration between 130 and 136 mEq per liter), if prolonged beyond a few hours, may provoke nothing more than an increased salt appetite.
Eichner : As Drs. Hiller and Nadel suggest, symptoms vary with how fast and far the serum sodium falls. Symptoms may be mild and nonspecific, such as fatigue, malaise, and nausea. Symptoms of moderate severity include headache, confusion, restlessness, disorientation, and slurred speech; such symptoms may reflect early cerebral edema. Or, as mentioned previously, symptoms may be severe, and include seizures, agitation, stupor, coma, pulmonary edema, and death. They tend to occur late in a race or in the first hours after a race. I know of hyponatremia after a race as short as 10km, in a man who ran the race and drank a lot of water in the hour or two after the race. Hyponatremia has also been reported in a woman who hiked into the Grand Canyon. I think that a warning sign for unrecognized hyponatremia may be a severe post-exercise headache that lasts 24 hours or so and is refractory to the usual headache remedies, such as aspirin and acetaminophen.
Noakes : The clinical presentation that we see most commonly in South Africa occurs typically in an athlete (most often female) competing in an ultradistance race, most usually the 90km Comrades Marathon footrace which lasts between 5.5 and 11 hours. Usually the athlete becomes aware of symptoms only after completing the race. Because serum sodium concentration is not frequently measured in collapsed athletes, the diagnosis of hyponatremia is often missed or mistaken for other common exercise-related conditions such as heatstroke or hypoglycemia. In my opinion, if the patient is unconscious, with a rectal temperature below 41-42 C, and a normal blood glucose concentration, the most likely diagnosis is hyponatremia.
Laird : As with most clinical diagnoses, things aren't often clearcut. I have seen athletes who were completely asymptomatic with serum sodiums in the upper 120's, while others are severely symptomatic. Discussions with the athletes after recovery often reveal that most knew they were in trouble, and some experienced feelings of extreme lethargy and a detached, almost floating sensation. Confusion and, sometimes, belligerence are common. In hospitalized triathletes, we often see positive personality changes soon after IV treatment.
What are the proposed mechanisms for the development of hyponatremia? Which mechanism do you think is operative?
Nadel : Hyponatremia results from large losses of the body's exchangeable sodium in sweat without sodium replacement in the ingested fluid. The average individual has about 3000 mg of exchangeable sodium, nearly all distributed in the extracellular fluid compartment. At an average sweat sodium concentration of 50 mEq per liter and an average sweat rate of 1.5 liters per hour on a warm and humid day, several hours may be required to generate a significant body sodium deficit. Excessive ingestion of sodium-free fluid during prolonged exercise, during which time renal function is reduced, may result in a significant dilution of the blood and subsequent hyponatremia.
Eichner : The strongest hypothesis, in my opinion, is voluntary overhydration with water (and/or other very hypotonic fluids) in the face of moderate sodium loss in sweat. This seems to explain the most severe cases on record, such as those reported by Dr. Noakes in 1985 and 1990, a report in Physician and Sportsmedicine in 1988, a study in the Western Journal of Medicine in 1993, and that of the woman in the Grand Canyon that I mentioned previously. In a study by Armstrong of symptomatic hyponatremia during prolonged exercise in the heat, the subject drank and retained way too much water.
Noakes : I don't think that findings of my research, or the research of many earlier investigators fully corroborate the statements of Drs. Nadel and Eichner. Studies done nearly 80 years ago suggested that hyponatremia was caused by the movement of sodium from the extracellular fluid into the unabsorbed water in the intestinal lumen, and recent work in our laboratory supports these findings. I would estimate the maximum rate of intestinal fluid absorption to be less than 1000ml per hour in most people. When fluid is ingested at higher rates, either at rest or during exercise, fluid may accumulate in the intestinal lumen, explaining the weight gain often reported in hyponatremic athletes. There is then likely to be a movement of sodium into this fluid, thus causing both the serum sodium concentration and the serum osmolality to fall.
Although a number of scientists and clinicians speculate that large sodium chloride losses are important in the etiology of hyponatremia, there is, in my opinion, no evidence to support this contention. A study by Irving et al. (see suggested reading list) specifically found that total sodium chloride losses in runners who developed hyponatremia were no different from losses in other runners who completed the same ultramarathon races with normal serum sodium concentrations. Further, I think that it is wrong that many investigators ignore the results of Irving's study, as well as the recent study by Armstrong et al., that indicate that hyponatremic runners are actually overhydrated, and not dehydrated.
Hiller : Despite Dr. Noakes' assertion, all of the race participants we've seen who were hyponatremic were also dehydrated, and we believe that the mechanism responsible for their hyponatremia was large sweat and urine sodium losses, coupled with ingestion of large volumes of sodium free fluids. In prospective studies of more than 1000 athletes, we have had only one "overhydrated" athlete, who gained 2 kg during the Hawaiian Ironman.
Laird : I fully agree with Dr. Hiller. The majority of the hyponatremic athletes at the Ironman are markedly clinically dehydrated, and the mechanism for their hyponatremia would appear to be related to high sodium losses in association with inadequate sodium and fluid intake. The incidence of hyponatremia at the Gatorade Ironman rises slowly, and peaks in athletes about 13-15 hours after the start of the race. It then falls in competitors who finish during the last 2-4 hours. If hyponatremia were entirely dilutional, I would expect the incidence to peak among the last athletes to finish.
What are the physiological characteristics that would predispose an athlete to hyponatremia?
Laird : I'm not certain. Intuitively, it seems that athletes who lose excessive sodium through either hypersweating or high sweat sodium concentrations would be at greatest risk.
Noakes : Our studies suggest that hyponatremia can happen to anyone, provided that the rate of fluid ingestion is greater than the maximum rate of urine production, which we consider to be limited by the maximum rate of intestinal fluid absorption. Athletes with the slowest rates of intestinal fluid absorption would appear to be at greatest risk because they will be more likely to develop a fluid excess, even at much lower rates of fluid ingestion. Once there is fluid retention in the intestine, hyponatremia will develop, as Haldane and Priestley showed 80 years ago, and as we have recently shown.
Nadel : People who have a high sweat sodium concentration are more susceptible to the development of hyponatremia than those who have a low sweat sodium concentration, because they will lose more sodium per unit of sweat lost. Sweat sodium concentration ranges from 20 to 100 mEq per liter of sweat, is genetically determined, and can be decreased considerably with training. Generally, those susceptible are the slower participants who are on the course (and sweating) for a longer period of time. These are, almost by definition, less-fit people who have a higher sweat sodium concentration.
Eichner : Other predisposing factors include compulsive water drinking before, during, and after the race, and starting the race sodium-depleted because of harsh salt restriction, or taking diuretics for hypertension (as was the case with two women in the Grand Canyon, who ended up with serum sodiums of 107 and 108 mEq per liter). Less common predisposing or contributing causes might be: 1) sequestering of sodium in the gut during the race, as Dr. Noakes stated; 2) nonosmotic outpouring of antidiuretic hormone, as from pain, stress, or nausea during the race; 3) abnormal renal function caused by nonsteroidal antiinflammatory drugs; or 4) mild Addison's disease.
How is hyponatremia best prevented?
Noakes : I believe that hyponatremia can be prevented by warning athletes that they should not consume more than about 900 ml/hr of fluid for more than a brief time either at rest, during exercise, or during the post-exercise recovery period. This concept is difficult for many physiologists to accept, but there may be a limited rate at which fluid can be replaced during exercise and this limit is likely determined by the absolute rate of intestinal fluid absorption. It would seem that the human was not designed with an unlimited capacity to replace the very high sweat rates that can be achieved on occasion during exercise.
Hiller : I think that prevention is accomplished through the intake of sodium during the exercise period, as well as increased sodium intake during the week prior to an endurance event. Mark Allen has demonstrated hyponatremia in the laboratory, as well as multiple hyponatremic episodes during races. He credits increased sodium intake with allowing him to win the Gatorade Ironman event.
Laird : Certainly in events involving continuous exercise for more than four hours a solution containing some sodium would be appropriate.. The conscientious ingestion of a water, glucose, and salt solution seems to be the primary factor in reducing the incidence of symptomatic hyponatremic dehydration at the Ironman.
Nadel : At the 1993 American College of Sports Medicine meeting, we reported that a rehydration drink containing 25 mEq sodium per liter provided better restoration of the body fluids lost during dehydration than did a drink containing either no sodium or 50 mEq sodium per liter. Our subjects voluntarily drank 46 ml of this drink per kg body weight (~3.2 liters) in three hours of rehydration, retaining 36 ml per kg (~2.5 liters) after urine losses. This was adequate to restore the lost fluid and electrolytes, and represents a greater sustained rate of fluid intake than that suggested by Dr. Noakes. Glucose in a rehydration drink promotes fluid intake, due to the sweet taste, and together with sodium promotes water absorption due to the fact that sodium and glucose are actively cotransported from the gut into the body. In our study, ingesting water alone resulted in significantly poorer body fluid recovery.
Eichner : I too believe that lightly salting your foods during hot-weather training, and consuming salty foods and beverages during long distance events are good means of prevention. And I agree with Dr. Noakes' advice not to overhydrate during a race: Don't drink more than you lose.
What advice would you give athletes and coaches about hyponatremia?
Laird : Coaches and athletes sometimes neglect the gut during training and, consequently, some athletes are chronically dehydrated and unable to adequately take in and retain fluids during exercise. I think that athletes should practice fluid intake during training, so that they are familiar with the process during competition. If the athlete begins to feel bloated, or fluid begins to slosh around in the stomach, it may indicate the need to decrease or curtail fluid intake temporarily, or to ease up on the intensity of the activity.
Nadel : Athletes must take care to restore the water and sodium losses incurred during exercise. Sweat losses are greater in warmer and more humid conditions than in cooler and drier conditions, and cumulative sweat losses are greater in longer events. In short events, water and sodium replacement can occur safely after the activity.
Hiller : I don't think that salt intake should be a major concern except in prolonged exercise. Individual losses differ by an order of magnitude, but for a race like the Ironman, an intake of at least 250 mg to 500 mg/hr can prevent hyponatremia in susceptible athletes.
Noakes : I believe that athletes should be warned not to drink too much either during or after exercise. Further, I think that more information must be disseminated to medical teams caring for athletes who collapse during or after ultradistance events. It seems that many believe that dehydration is the only possible fluid balance disorder that they are ever likely to encounter, and that all athletes who collapse during or after exercise must have a heat-related disorder. Usually, providing fluids to a collapsed, hypernatremic athlete is innocuous. However, giving intravenous fluid at fast rates to a subject with hyponatremia is definitely contraindicated and could be fatal. Perhaps the real danger of hyponatremia is that its seriousness is underestimated. In my opinion, hyponatremia is potentially the most dangerous current threat to the health of the ultraendurance athlete because it is poorly recognized, it is difficult to treat, and it will be exacerbated by inappropriate treatment, as we have seen on more than one occasion in South Africa.
Eichner : I don't know if we can indict all fluids. Certainly, if ingesting too little water can kill you, so can too much. Water doesn't provide sodium. On the other hand, salt tablets generally provide too much sodium. We need a happy medium because it's clear that ingesting sodium can be beneficial.
"I just can't make a point without putting somebody down. But if you can't accept that, then you're the one in the wrong here."
Someone is shipping water to the United States from the island of Fiji?
That sounds a tad bit expensive and not very intelligent.
Links work too.
I've also found that Clevelanders enjoy poking fun at their city as much as anyone. I wouldn't be surprised if Fiji's little joke on the label didn't help sales of their water there.
However, Cleveland's intentional misrepresentation that Fiji's water might be poisonous might be grounds for a lawsuit if it hurts their sales.
ROTFL
Interesting history on all that; Los Angeles won all water rights way back when and a man doesn't even own the spring on his own property anymore.
Grounds for a Lawsuit? wouldn't hold water............
What great posts! One for the DIYer and one for the rest.
The Brita filter on my tap costs $20, works great, and gets relaced every three months or so.
There is a company in England that ships bags of sand to Saudi Arabia -- it's high quality mortar sand, but still -- they are selling sand to Saudia Arabia.
Really??? I must be a sucker because I only get 750 ml and pay over $40 for it. ;-)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.