Hydration advice for athletes has changed dramatically over the last ~100 years and we've taken a look at how things have changed during that time...

Early 1900s - "Drink nothing"

The changes over time has been most clearly documented in the writings of Prof. Tim Noakes, along with two prominent ex-sports science students from his department at the University of Cape Town; Ross Tucker and Jonathan Dugas.

Their research into hydration concluded that, in the early 1900s, it was considered best practice to advise athletes to drink nothing, or as little as possible, during all athletic pursuits.

They highlight a quote from James E. Sullivan, Head of the Amateur Athletic Union, from 1909)

1965 - The first sports drink

Then things started to change.

1965 was the year that Dr Robert Cade came up with the first iteration of the sports drink that eventually became known as ‘Gatorade’.

It was developed to combat the fatigue that the University of Florida football team - ‘The Gators’ - suffered in the oppressive heat and humidity that Florida is famous for.

The hypothesis was that this fatigue was often being caused by a combination of carbohydrate depletion, dehydration and electrolyte loss.

So a drink formulated with sugar, salts and water was developed and found to be remarkably effective.

Gatorade got off to a great start commercially and was named a sponsor of the NFL in 1969.

Rising sales led Gatorade’s marketers to promote the positive benefits of drinking and, increasingly, highlight the dangers of dehydration.

 

 

In 1985, the Gatorade Sports Science Institute was set up.

It’s stated mission is to “help athletes optimize their health and performance through research and education in hydration and nutrition science”.

In the 80s and 90s, GSSI conducted studies into the effects of dehydration on performance.

Many of these studies appeared to demonstrate that dehydration was a serious  performance limiter, especially during endurance sports in the heat.

And, over time, this message gradually became established as ‘fact’ within the sporting community.

1996 - "Replace 100% of Sweat Losses"

This reached its height in 1996, with the American College of Sports Medicine’s, ‘Position Stand on Exercise and Fluid Replacement’. It included the statement:

During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating or consume the maximal amount that can be tolerated.

The movement from ‘nil by mouth’, to ‘consume as much as can be tolerated’ is one of those classic ‘pendulum swings’ in the world of sports science. Other examples include the High Carb vs Low Carb diet debate and Cushioned, Supportive running shoes vs Barefoot Running.

These polarisations tend to occur because human brains love simple answers and ‘either/or, black or white’ debates. We struggle with grey areas, even though that tends to be where the answers to complicated questions often reside!

Prof. Tim Noakes was amongst the first to question whether the ‘drink, drink, drink’ philosophy’ was really a good idea.

He uncovered a growing number of cases of hyponatremia - a sometimes fatal condition characterised by low blood sodium levels - in an increasing number of endurance athletes who had seemingly followed advice to drink as much as they could.

Noakes went on to write a thoroughly researched and emotionally-charged book called ‘Waterlogged. The Serious Problem of Overhydration in Endurance Sports’.

In this he suggests that hyponatremia has become a significant problem largely
because of the marketing efforts of the sports drink industry.

He makes the tragic point that there have been a number of preventable deaths
from over-drinking and that these could have been avoided with more balanced messaging.

 

 

It’s impossible to argue that the the sports drink industry, has not been influential in over-emphasising the dangers of dehydration and this counter argument has definitely started to have an impact.

2007 - Prevent >2% dehydration

In 2007 the American College of Sports Medicine updating it’s guidelines:

The goal of drinking during exercise is to prevent excessive Dehydration (>2% body weight loss) and excessive changes in electrolyte balance to avert compromised performance.

Because there is considerable variability in sweating rates and sweat electrolyte content between individuals, customized fluid replacement programs are recommended.

Individual sweat rates can be estimated by measuring body weight before and after exercise.

This was definitely a significant step away from ‘drink as much as tolerable’,
but it’s correctness and practical usefulness to athletes has still been challenged.

Noakes and his supporters cite numerous examples of world-class performances occurring when dehydration has exceeded 2%, sometimes by a significant amount.

Like when marathon runner Halie Gebraselassie lost almost 10% of his body weight during a 2:05:29 marathon winning performance in Dubai in 2009.

Data collected on large numbers of IRONMAN finishers in New Zealand and South Africa shows that most of the field ended up significantly dehydrated at the finish line and that some of the faster finishers were in fact some of the most dehydrated of all, losing in the region of 2-7% of their bodyweight.

This kind of evidence, along with real world experience from endurance athletes, suggests that an arbitrary, 2% dehydration limit is neither useful, nor correct in all scenarios.

The truth is significantly more complex and seeking a simpler, ‘one-size-fits-all’ solution can be counter-productive.

 

What's the best approach to hydration?

At the sharp end, it seems that opinion is moving towards a view that, whilst drinking to thirst is a sensible approach for shorter or lighter activities, during very long events in the heat, when total sweat and electrolyte losses are high, replenishment might need to be approached more proactively than would be the case in shorter bouts of activity. 

Examples of the efficacy of this approach include this 2015 study by researchers in Spain, which showed faster racing times for athletes given salt supplements during a middle distance triathlon compared to a control group given placebos. 

Here’s what 2016 Ironman 70.3 World Champ Tim Reed has to say about drinking to thirst...

 

Together, I think these two examples illustrate very nicely that, whilst drinking to thirst is a sensible guiding principal and basis for how to approach hydration for shorter/low sweat activities, a more proactive and individualised approach is probably what's needed for longer, hotter and sweatier events where drinking water to thirst is unlikely to sufficient to maintain optimal performance and health.

Other scenarios where a pre-planned, but flexible and personalised, approach might be beneficial include...

1) During moderate duration, high intensity activities where the maintenance of blood volume to assist cardiac output, heat dissipation and other metabolic challenges is very important.

2) During days and weeks of back-to-back, hard or high intensity training or competition in hot conditions, where cumulative sweat losses have the potential to cause stepwise depletion in fluid and electrolyte levels in the body.

3) When individuals have exceptionally high sweat sodium losses and need to be more aggressive with replacement protocols to balance those out.

4) When the athlete is inexperienced and so all of the sensations associated with pushing their bodies very hard are relatively new and difficult to interpret accurately.

5) In environments where opportunities to access fluids are limited or constrained.

6) Where drinking at certain times and abstaining at others can be tactically advantageous, such as in bike racing or Long Distance triathlons.

Hopefully this brief summary of a hundred years or so of hydration advice leaves you in an informed position from which you can start understanding your own individual hydration needs and refine your strategy from there

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ALL Information collected from = https://www.precisionhydration.com/performance-advice/hydration/history-of-hydration-advice-for-athletes/