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Updated 06 October 2015

Tim Noakes on overhydration in athletes

For the past three decades athletes have been told to drink as much as they can. Overhydration, however, can be fatal in endurance athletes, sport scientist Tim Noakes warns.

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"Drink as much as you can, even before you feel thirsty." That's been the mantra to athletes and coaches for the past three decades, and bottled water and sports drinks have flourished into billion-dollar industries in the same short time. The problem, however, is that an overhydrated athlete is at a performance disadvantage and at risk of exercise-associated hyponatremia (EAH) - a potentially fatal condition, sport scientist Tim Noakes warns.

In his latest book Waterlogged:  The Serious Problem of Overhydration in Endurance Sports - Human Kinetics, 2012), Noakes exposes the myths surrounding dehydration and presents up-to-date hydration guidelines for endurance sport and prolonged training activities.

The following is an excerpt:

When I began running in 1969, completing my first 42 km (26 mile) marathon in September 1972, we were advised to drink sparingly, if at all, during exercise. As I recall, that race provided only one “refreshment” station at 32 km (20 miles); there, our running times were also recorded, perhaps as proof that we had indeed been present at least at one point on the race course.

This approach had been followed ever since marathon running became an official event in the first modern Olympic Games in Athens in 1896. Until the 1970s, marathon runners were discouraged from drinking fluids during exercise for fear that it would cause them to slow down. For some, drinking during marathon running was considered a mark of weakness. My childhood running hero and subsequent friend, Jackie Mekler, five-time winner of the 90 km (56 mile) South African Comrades Marathon, described the drinking philosophy of runners with whom he had competed before his retirement in 1969: “To run a complete marathon without any fluid replacement was regarded as the ultimate aim of most runners, and a test of their fitness” (Noakes, 2003, p. 252).

Marathon runners were not alone in this belief. Cyclists in the race that was considered the ultimate physical challenge - the Tour de France - were advised similarly: “Avoid drinking when racing, especially in hot weather. Drink as little as possible, and with the liquid not too cold. It is only a question of will power. When you drink too much you will perspire, and you will lose your strength.” As a result only “four small bottles for a long stage (of the Tour), it was frowned upon to drink more” (Fotheringham, 2002, p. 180).

Plateau in running times

There is no evidence that this advice was especially dangerous, produced ill health or death, or seriously impaired athletic performance. Indeed, the most rapid improvements in marathon running performances occurred from 1920 to 1970 in the period when athletes were not drinking much during races and were generally ignorant of the science of distance running, including the value of specific diets (Noakes, 2003).

A plateau in running times occurred after 1970. This effect is most apparent in the 42 km marathon, suggesting that all human runners, marathoners especially, are rapidly approaching the physical limits of human running ability. Note that in the period of 1900 to 1970, marathon runners were actively discouraged from drinking during exercise. The introduction and encouragement of frequent drinking after 1976 were not associated with any sudden increase in world-record performances in the marathon. Rather, an opposite trend is apparent. The same trend exists also at the shorter–distance races, during which athletes do not usually drink.

The notion that athletes should drink during exercise took hold rather slowly. In November 1976 the prestigious New York Academy of Sciences (NYAS) held a conference titled “The Marathon: Physiological, Medical, Epidemiological and Psychological Studies” (Milvy P., 1977). The conference coincided with the first running of the New York City Marathon through the five boroughs of the Big Apple.

The race was a major success, launching the concept of the big-city marathons and stimulating an unprecedented growth in marathon running in particular and endurance sport in general. Thus, entrants in the New York City Marathon climbed from fewer than 2 000 in 1976 to more than 10 000 in 1980, reaching 30 000 by the late 1990s. Similar rates of growth were seen in the Boston and London Marathons, among many others.

No speaker at the NYAS conference on the marathon spoke exclusively on the role of fluid ingestion during exercise. Fluid balance during exercise was discussed only fleetingly because it was considered to be of little scientific relevance.

Fixx's new approach

James F. Fixx, a writer from Riverside, Connecticut, who had begun running in the late 1960s - in the process losing 27 kg (60 lb) and completing six Boston Marathons - was an especially attentive attendee at the 1976 NYAS marathon conference. He came to acquire the medical and scientific information necessary for completing a book titled The Complete Book of Running (Fixx, 1977) that he had begun writing in April 1976. When published a year later, the book became an instant phenomenon, topping the New York Times best-seller list for 11 weeks and selling over a million copies. It was subsequently translated into all the major languages.

In The Complete Book of Running, Fixx wrote the following: “Drink lots of water while you’re exercising. It used to be considered unwise to drink while working out. Recent studies have shown, however, that athletes, including runners, function best when allowed to drink whenever they want to [my emphasis]. A 5% drop in body weight can reduce efficiency by 15%, and 6% is about the maximum you can comfortably tolerate."

Perhaps Fixx’s summary of the “state-of-the-art” guidelines gleaned from the 1976 NYAS marathon conference was that runners should drink according to the dictates of their thirst (“drink whenever you want to”) and should not lose too much weight during exercise since this causes an impaired “efficiency”. Interestingly, he made no reference to any dangers caused by dehydration in those who drank little and lost substantial amounts of weight during exercise. Rather, he reported that a loss of up to 6% of body weight could be “comfortably tolerated”. This confirms that Fixx did not hear anything at the NYAS conference or elsewhere proposing that runners should drink as much as tolerable in order to prevent any weight loss during exercise.

Explosion in number of marathon runners

The sudden global growth in the number of marathon runners in Europe and North America soon generated a potential market for those selling products used by runners. James Fixx was himself perhaps the first to benefit through the sales of his book, unmatched by any subsequent book on running. Other beneficiaries would be Nike running shoes followed closely by the sports drink and nutritional supplement industries.

I visited New York in 1976 to attend the NYAS marathon conference and to run the marathon. I wished also to take home some Nike running shoes, then unavailable in South Africa. To do this, I was forced to travel the length and breadth of New York City. Eventually I found the single shop in the entire city that specialised in running shoes. The subsequent growth of Nike would parallel the growth in the number of runners in the New York City Marathon.

It predated the growth in the sports drink and nutritional supplement industries by some years.

Until then, there had been little incentive to study endurance exercise because the only sports with money were the professional sports such as American football, basketball, and baseball and, to a lesser extent, golf. Sports medicine encompassed the orthopedic and medical care of professional athletes injured in those sports. The physiological needs of endurance athletes were not considered  particularly important. Frank Shorter, the American winner of the 1972 Munich Olympic Marathon and the person held accountable for the subsequent growth of marathon running especially in the United States, wrote at the time that people expressed their disbelief whenever he referred to himself as a “professional marathon runner”. What sort of profession was that? they wondered.

But the tipping point occurred after 1976 with the sudden explosion in the number of marathon runners entering races, especially in the United States. This would provide a massive new market not just for running shoes but for a novel product, a sports drink for use during exercise, which had been developed in the late 1960s by a renal physician, Dr Robert Cade, working at the University of Florida.  

Selling an image

Already by 1976 his product had become a runaway commercial sensation in the United States, soon establishing itself as an essential ingredient for success in American football. The product also claimed medicinal properties. While it could enhance athletic performance, it could also prevent and cure dehydration, heatstroke and muscle cramps. Before long, its manufacturers would begin to eye the much greater numbers of the physically active, including this new population of joggers aspiring to become marathon runners.

But Dr Cade’s product faced some significant challenges. First, if drinking during exercise was so important, then why should a product that contains no unique molecules (i.e. a product that was not discovered in an ultra-sophisticated laboratory after decades of intensive research including thousands of heart-wrenching failures) ever be taken seriously, especially if its core ingredients are chemicals present in even the most rudimentary kitchen – glucose, salt, water, and a dash of lemon? Second, how does one advance substantive medical claims in the absence of proof of efficacy?

Thus, the challenge faced from the outset by those manufacturing Dr Cade’s product was to sell a drink consisting of common kitchen chemicals on the basis of scientific evidence that did not exist in the 1960s and that some would argue still does not exist even today. The commercial success of Gatorade confirms the effectiveness of modern marketing tactics and the strength of a unique, positive product image.

“Advertisers have dispensed with the idea of promoting a product’s attributes in favour of marketing the product’s image. This image is conceived by marketing psychologists quite independently of the product itself, and usually has more to do with a target market than the item being sold” (Rushkoff, 2000, p. 19).

Indeed, the marketing of drinks claiming medicinal properties, of which Coca-Cola was the first global success, led to the following conclusion: “Patent medicine makers were the first American businessmen to recognise the power of the catchphrase, the identifiable logo and trademark, the celebrity endorsement, the appeal to social status, the need to keep ‘everlasting at it’. Out of necessity, they were the first to sell image rather than product” (Pendergrast, 2000, p. 11).

Incorrect advice results in new medical condition

Thus, “Like all great love affairs ours depends to a large extent on creating a set of illusions, feelings that we are special. We are who we are because we are all things to all people all the time everywhere” because “we’re selling smoke. They’re drinking the image, not the product” (p. 443). So it was that a drink, with ingredients that are freely available and cheap, became iconic.

One might argue that this is simply the reality of the modern world and that we are naïve to expect otherwise. But it is disturbing that incorrect advice to the public and the public’s own susceptibility to effective promotional efforts resulted in a novel medical condition that affected thousands of soldiers, hikers, runners, cyclists, and triathletes, causing some to die. Sadly, this phenomenon and the deaths that apparently resulted from it were preventable.

This story also is a cautionary tale about how a movement can take hold and manifest itself into something unhealthy and potentially very harmful. As bad as water restrictions and required ingestion of salt tablets were during the 1960s, so too is the current nearly universal notion of drinking despite a lack of thirst.

Today, athletes, parents, coaches, and even many professionals in medicine, fitness and sport science push the intake of fluid far beyond the bounds of what solid research suggests. Indeed, tens of millions of athletes and fitness enthusiasts are waterlogged in that the hydration practices to which they religiously adhere adversely affect their health and performance.


Read more:

Too much water could be dangerous
Tim Noakes on carbohydrates
Running: all the info you need

 
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