Letter to the editor.

Regarding the "Consensus Statement of the First International-Associated Hyponatremia Consensus Development Conference" published in the Winter 2005-2006 AMAA Journal:

This article raised several questions that I believe must be answered to more accurately access and incorporate the findings:

1. Was any consideration given to the kind of water used by the athletes? For example, in my limited knowledge of water, there is a major difference between tap water, some bottled water, distilled water, spring water, and so on. Tap water in San Diego has an ORP (oxygen reduction potential) of 700-800. Some artesian water from New Zealand has an ORP of 30-40. Some companies such as Drinking Water Solutions now make water that has an ORP of 0 or less. The less the ORP the more beneficial the water, especially in recovery.

2. Also, the PH of water supposedly plays a role in determining whether the water will be moved into the cells. Many believe that the water should be slightly alkaline rather than acidic in order to be readily assimilated. Was this measured?

3. Was any consideration given to the amount of extra- and intra-cellular water? For those who "drank too much water," was it an accumulation of extra-cellular water? The balance between intra- and inter-cellular, from what I understand, plays a major role in how well-hydrated the body is or can be. Also ionized water appears to be more effective. (For example, this is the kind of water used by Lance Armstrong after his workouts.)

Michael Yessis, PhD

Professor Emeritus, CSUF

President, Sports Training, Inc.

Co-author Arthur Siegel, MD, responds:

EAH may occur when ingestion of ANY hypotonic fluid (including sports drinks) is accompanied by weight gain or positive fluid balance during exercise. The aspects raised in Dr Yessis' letter do not alter this risk.

Regards, AJS

Co-author Tamara Hew-Butler, DPM, responds:

Dear Professor Yessis,

Thank you for raising some interesting questions in regards to the "Consensus Statement of the 1st International Exercise-Associated Hyponatremia Consensus Development Conference." First, let me clarify that this statement was formulated by a review of all evidenced-based literature; none of which took into account the ORP, pH, or ionization of the fluid ingested. The movement of fluid between the intra-cellular and extra-cellular space is primarily dictated by effective osmolality (1); with the effect of ORP, pH, and ionization negligible factors in total body water distribution. I have answered your queries below and welcome any further scientific documentation supporting the physiological benefits of ionized water to which I am unaware.

1. There may be differences in the mineral and bacterial composition of the various tap, distilled, spring, and bottled water but unless these solutions contain solutes that are impermeable to the cell membrane, these apparent "differences" would not influence the distribution of total body water.

The measure of oxygen-reduction potential (ORP) is currently used as the primary approach to standardize water disinfection parameters and reflects the antimicrobial potential of the water irrespective of water quality (2). The advantage of water with a high ORP (650 to 700mV) is that free-floating decay, spoilage bacteria, and pathogenic bacteria such as E.coli and salmonella are killed within 30 seconds (2). Conversely, water with a negative ORP (-300 to -400mV) has been hypothesized to facilitate optimum growth of strict anaerobes in the gut (3). There is no scientific evidence supporting the claim that water with a lower ORP could possibly "enhance" recovery from exercise.

2. Beverage pH has minimal impact on the pH of the body (4) and is not a factor in the movement of water between the extra- and intra-cellular space. The concept that ingesting a more alkaline beverage would enhance the intra-cellular movement of water seems physiologically implausible. The amount of fluid ingested in proportion to the amount of total body water is generally not enough to influence the pH of the system, chemical buffers within the body can respond to alterations in pH in milliseconds and the total concentration of hydrogen (H+) ions in the blood is 40 nmol/L while the concentration sodium (the main effective solute in the body) is 140 mmol/L (~3.5 x 106 the concentration of H+) thus negating any effect of beverage pH on overall tonicity.

3. Water moves freely between intra-cellular and extra-cellular compartments in response to osmotic pressure gradients created by effective solutes (Na+, K+, and mannitol) that are impermeable to the cell membrane (1). If we measure a serum sodium concentration below 130 mmol/L, the amount of total body water in the extra-cellular and intra-cellular compartments is in equilibrium; however, the concentration of sodium is below the normal reference range because total body water is in excess to total exchangeable sodium (dilutional hyponatremia) or excessive sodium losses (depletional hyponatremia) have occurred. The use of "ionized" water will have little impact on body fluid distribution for reasons detailed above.

Sincerely,

Tamara Hew-Butler, DPM

PhD candidate

Department of Human Biology

University of Cape Town 

REFERENCE

(1) Verbalis, JG. Disorders of Body Water Homeostasis. Best Practice and Research Clinical Endocrinology and Metabolism. 2003;17(4):471-503.

(2) Suslow, TV. Oxidation-Reduction Potential (ORP) for Water Disinfection Monitoring, Control and Documentation. University of California Division of Agriculture and Natural Resources. 2004; 8149:1-5.

(3) Vorobjeva, NV. Selective Stimulation of the Growth of Anaerobic Microflora in the Human Intestinal Tract by Electrolyzed Reducing Water. Medical Hypothesis. 2005;64:543-46.

(4) Shoenut, JP, et al. Impact of Ingested Liquids on 24-hours Ambulatory pH tests. Digestive Diseases and Sciences. 1998;43(4):834-9.