When you have coached and worked with runners as many years as I have had the good fortune to do so, you develop an innate ability to recognize many runners from a distance by observing their running form. This is especially true for athletes who I see on a regular basis. With the exceptions of many elite Kenyans or even Ethiopians, most runners have very different styles of running. Some are extremely efficient while others have glaring asymmetry.
During the past decade I have become somewhat confused and almost perplexed at the number of runners who have enhanced their asymmetry and distorted their running form by carrying needless containers of either water or some other fluid replacement. Some carry “handhelds” while others strap devices to their backs in their attempts to “keep hydrated.”
Is this really necessary? Do they really believe they will become dehydrated on a training run of two hours or less? If so, the marketers of such products (containers and sports drinks) have been extremely successful in their promotions as they exaggerate our need for daily fluid consumption.
Dehydration refers to a deficit of the total amount of water in the body with an accompanying disruption of metabolic processes. Dehydration may also be a cause for hypernatremia, which is elevated sodium content in the blood. The loss of plasma fluid (water) results in an increased percentage of sodium in the plasma. Water is lost in a variety of ways including perspiration, minimal losses from breathing and also from urinating and bowel movements.
Since in most cases runners are not urinating or stopping to empty their bowels frequently during a training session, perspiration is the major cause for loss of fluid/water.
One of the common current myths is that you should drink as much as you can tolerate so that you maintain fluid levels during your run. However, that may not be the case. The human body has evolved an exquisite system to regulate water consumption and it is called “thirst”. The body is well equipped to deal with transient dehydration, which usually lasts from 4 to 8 hours. It is chronic dehydration, which lasts for days, that leads to health issues.
The human organism reacts to applied stress by adapting and compensating so that it can function at an elevated level once the adaptation has occurred. This is the “training effect.” It may also be the case with fluid intake and replacement.
Dr. Tim Noakes, a South African physician, researcher and author, has written thousands of pages on running. One of his most intriguing books is entitled “Waterlogged—the serious problem of over hydration in endurance sports.” The book devotes 428 pages to the subject. Believe me, those are a lot of pages to discuss hydration and the potential issues of “water intoxication.”
His interest was spurred by the death of Cynthia Lucerno, Ph.D., who passed away a few hours after stopping at the 22-mile mark of the 108th B.A.A. Boston Marathon in 2002. Her death was attributed to “hyponatremia” or “water intoxication.”
The basic premise of the book is that man is the best-equipped land mammal to perform with limited amounts of water intake, if replenished appropriately following exercise. Noakes informs us, “The biological record appears to give a consistent answer. Humans developed as long-distance runners especially well adapted to run in extreme dry heat in the middle of the day while drinking infrequently and conserving sodium stores. Humans are bipedal, reducing the radiant heat gain from the midday sun. Through evolution, we have developed adaptations that allow both superior thermoregulation and the ability to run economically for prolonged periods. The key is the number of sweat glands in human skin.”
A potential disadvantage of sweating is that it reduces total-body water content, which may cause dehydration. “Once the reduction in body water causes the solute concentration, especially the sodium concentration of the blood to rise, the brain detects the change and develops the symptom of thirst. This is a normal biological response that has evolved in most creatures to ensure that they maintain a constant body water content at least once a day (usually following the evening meal).“
The primary symptom of water loss is thirst. The human body has mechanisms that produce the thirst sensation. Other symptoms indicating dehydration include the color and viscosity of one’s urine output. Slightly yellow usually indicates “normal” total-body water content, while a dark and thicker void indicates dehydration and very clear urine may be indicative of hyperhydration.
Young children many times get thirsty very easily during activity. However as their body matures, the thirst sensation usually is delayed until later or following short periods of activity. Trained athletes usually don’t need fluid replacement until later in or even after their respective work bouts, but this is mostly dependent on the environmental conditions and the amount of sweating produced.
In our experience, our elite distance runners regularly complete longer runs of two hours without ingesting fluids. Their bodies have adapted. Without the necessity of “carrying” water bottles, they can maintain good running form and operate at a very efficient level. However, they do replenish with appropriate fluids once the run is completed and continue until their total-body water is back to normal (usually during the evening).
Non-elite runners would benefit more by not carrying fluids and focusing on having better form and efficiency in training runs of less than two hours. Another reason to not carry water on runs shorter than two hours is that research has indicated that more adaptation occurs when the organism’s water content is 1-2% decreased. It is sometimes referred to as the “quart low” theory, although the unit “quart” should not be taken literally. So it is actually beneficial to lose some fluid during training so that you force the appropriate adaptation, become more efficient and increase your fitness. The “super-compensation effect” is not promoted when your body maintains the status quo of pre-training bout levels.
So, unless you are running more than two hours, you really don’t need to carry those containers unless the conditions are extremely harsh. Pre-hydrate a few hours before your run and re-hydrate with more than just water following your run and throughout the evening.
Mike Caldwell is director/coach of ASICS Greenville Track Club-ELITE. This blog was originally written for and published in the Summer 2016 issue of PACE Running Magazine.