“Are you drinking water?” “Drink water!” “Hydrate!” “If you’re thirsty it is too late, you are already dehydrated.” This craze of hydrate, hydrate, hydrate has gone overboard and could be causing more harm than good. Who is more at risk for serious medical complications, the hyper-hydrated or dehydrated. For performance, is it best to be overly hydrated, dehydrated or euhydrated? What follows might surprise you.
Doctor Tim Noakes, MD a long-time researcher of water balance and author of “Waterlogged: The Serious Problem of Overhydration in Endurance Sports”, says we have been misled to believe that we need to drink to stay ‘ahead of thirst’. How have we been misled? First, we can thank the hydration industry for funding dubious science. Second, the fear mongering media jumps on board and purports untrustworthy science. And finally, we confuse the issue by generically using the term “dehydration” to describe the symptoms of heat exhaustion, heat cramps, or heat syncope.
Before I go further, let me clarify that I am NOT saying dehydration is a good thing. It is well-documented that a loss of just 2% of body water yields performance loss. When we have dehydration of 5% we enter a level for more serious health risk. However, that does not mean we should overhydrate. Our obsession with hydration puts us at risk for water intoxication, which has serious consequences. A 2% increase in total body water leads to generalized edema that can impair physical and mental performance (1).
For athletes, overhydration leads to performance loss and puts athletes at risk for exercise-associated hyponatremia (EAH) or exercise-associated hyponatremia encephalopathy (EAHE) –a potentially fatal condition. Oftentimes when an athlete collapses our first order to triage is to rehydrate. However, according to Noakes, the two most likely exercise-related causes of collapse during exercise are heat stroke and EAHE (2). Adding more fluid could exacerbate the issue. Intravenous fluid therapy should only be given if the athlete has elevated blood sodium concentration levels (hypernatremia). Take a look at the table below and note that the signs and symptoms of EAH, EAHE, and heat-illness are similar.
Signs and Symptoms of EAH, EAHE, Dehydration, and Heat Exhaustion
|Nausea||Headache||Dry mouth / Thirst||Confusion|
|Vomiting||Altered level of consciousness||Weakness||Fainting|
|Impaired exercise performance||Convulsion/Seizure||Confusion||Headache|
|Inability to sweat||Profuse sweating|
Ironically, I was working at a hydration station during the Illinois Marathon last weekend.. I witnessed several runners being carted away by emergency medical crews and all had an IV hooked up. Now, I was not the attending EMT. I did not perform the initial assessment, but all of these individuals required IV? Assuming the athletes hydrate before the run and have access to water all along the course, did all of these athletes truly need an IV? Where they all dehydrated, or were they suffering from other conditions? A study published in the British Medical Journal(2007) examined twenty-six U.S. marathons over this thirty-year period. The authors found four deaths from water intoxication and hyponatremia and zero from dehydration.
Two old and likely dated position stands have recommendations that could lead to overhydration. American College of Sports Medicine (ACSM, 2007), recommends drinking 20 to 40 fl oz per hour before and during endurance events (3). The NATA position statement of 2000 says athletes should consume approximately 17 to 20 fl oz 2 to 3 hours before exercise and 7 to 10 fl oz 10 to 20 minutes before exercise for a total of 24-30 fl oz. Unfortunately, this may be excessive. As fluid intake exceeds 800 ml (27 fl oz) our risk for EAH increases, and for fluid intake over 1000 ml (34 fl oz), the risk goes up significantly. Two major organizations recommend fluid intakes that put athletes at risk. Maybe it is time we reexamine these standards?
Then there is the issue of hydration on performance. Much like adding water to gas, we are diluting our fuel. Adding water to blood dilutes sodium, potassium, and other needed elements required for performance. Studies show that when athletes exercise at euhydration levels performance is optimal. Performance gradually declines as we move further from euhydration to hyper-hydrated or dehydrated.
A study released by the NSCA demonstrated that pre-exercise consumption of an energy drink did not improve cycling performance. In addition, the data indicates that energy drinks induced greater inflammatory-related responses than caffeine and carbohydrate supplement or a Placebo (sparkling water) (5). Even more, consumption of energy drink elicited mild hypoglycemia during cycling (5). The authors conclude that coaches and sports medicine personnel should be cognizant of consumption timing before competition and remember that energy drinks contain a significant glucose load.
The final advice from Tim Noakes is that athletes “should drink at one’s own discretion and listen to their internal thirst mechanism”. Dr. Noakes states we should aim for ingestion rates that never exceed 800 ml/hr (27 ounces)(2). If you maximize performance stay balanced – not too much, and not too little. Instead of drinking to prevent thirst, listen to your thirst mechanism and drink at thirst. Remember this should not be taken as the Gold Standard. Everyone is different. Experiment with various hydration strategies to learn what works best for you. Try different sports drinks in varying amounts, and hydrate at different times during your workout to discover the optimal mix.
That is all for now. Whew – I’m thirsty, time for some water.
1. Cohen, D. The Truth About Sports Drinks. BMJ 2012;345:e6096
2. Noakes, T. Waterlogged: The Serious Problem of Overhydration in Endurance Athletes. Human Kinetics. Champaign, IL. 2012.
3. ACSM. ACSM Position Stand; Exercise and Fluid Replacement. Med Sci in Sport and Ex.2007; 39(2)
4. Casa,DJ, et. al. National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. NATA Journal of Athletic Training 2000;35(2):212–224
5. Phillips, MD, Rola, KS, Christensen, KV, Ross, JW, and Mitchell, JB. Preexercise energy drink consumption does not improve endurance cycling performance but increases lactate, monocyte, and interleukin-6 response. J Strength Cond Res 28(5): 1443–1453, 2014.