Fluid or hydration status is extremely important in endurance sports like the marathon, getting it wrong can have disastrous consequences. As such hydration is a balancing act, not taking in enough fluids will result in dehydration and taking in too much fluid will result in Exercise-Associated Hyponatremia (EAH). EAH can be a life-threatening scenario where an athlete or individual takes on more fluid than they are losing, causing a dilution and subsequent reduction in sodium levels within the body resulting in fatigue, nausea, vomiting, dizziness and alterations in consciousness.

How Fluid Should Be Replaced

It is uniformly agreed that fluid replacement during exercise is important to prevent excess fluid loss (dehydration) and to avoid body weight loss of >2% and excessive changes in electrolyte balance which can compromise performance. How that fluid is replaced during exercise is currently of great debate with researchers unable to come to a consensus on which approach is best, drinking to a plan of 600-800ml per hour, drinking to thirst (using the sensation of thirst to determine when to drink) or drinking ad libitum (drinking whenever and in whatever volume). In light of this lack of consensus it would seem reasonable that any rehydration strategy should be flexible taking into consideration the duration of the event, the outside temperature, the effort required, sweat rate, the terrain and gradient etc. It should use thirst as a guide while not straying too far from an intake of 600-800ml per hour, but essentially not drinking more than is being lost through sweat.

Sweat Rates

Sweat rates are highly variable between individuals with an average sweat rate of approximately 1.35L/hr. There are calculators available that can help determine ones specific sweat rate. Alternatively, a simple way to establish a rough sweat rate is to weigh one’s self prior to and immediately after a 60 minute workout. The weight loss during that period divided by the time (60mins) will provide a rough sweat rate estimate – it is important to be well hydrated before undertaking the workout. The benefit of establishing an individual sweat rate estimate is it aids in understanding how much fluid is lost to sweat per hour of exercise and therefore roughly how much fluid will need to be replaced per hour.

What To Drink

Armed with a sweat rate estimate and a rehydration strategy of drinking to thirst while making sure one isn’t straying too far from the amount of fluid needing to be replaced due to sweat loss, gives you 2 of 3 key components to a solid hydration strategy. The final component is the fluid type that should to be taken in; water, hypertonic (Gatorade), hypotonic (Mizone) or isotonic (Powerade) drinks. In endurance sports the simple answer to this question is all, it is important to use a mixture of water and drinks that contain electrolytes as well as carbohydrates. Lastly, it is important to try different products and combinations during training to see what works best and to also get used to drinking while training, so when it comes to race day it is one less thing you have to think about.

Supplements Are Big Business!

Sports nutrition supplements, more formally known as nutritional erogogenic aids are part of a supplement industry that is currently booming, with sales in Australia skyrocketing to $1billion dollars per year. It is not hard to miss manufacturers bold advertising campaigns, their lists of powders, pills and liquids for pre workout right through to post workout and recovery, all there to help you “train harder” and achieve “mass gains”. If you do miss the advertising, you cannot miss the plethora of blogs and websites dedicated to sharing what the “best” performance supplements to take are.

Do Supplements Really Work?

But do these advertised supplements actually work? The simple answer is well summed up by Professor Ron Maughan who said “if it works, it is probably banned (by WADA). If it is not banned, it probably doesn’t work.” However, there are some exceptions that we will get to. For elite athletes subjected to drug testing, ergogenic supplements can be a challenging area. Studies show high rates of contamination among supplements with one study ranging from 12-58%, predominantly for prohormones and stimulants. There are also everyday health considerations for non athletes, do you want to be ingesting a supplement containing a banned substances?

How To Protect Yourself From Banned Supplements

Thankfully there are some tools out there to help athletes and individuals to navigate through the challenging world of ergogenic supplements. There are fantastic sites like informed-choice who independently test batches of supplements to determine if they contain banned substances. The Australian Institute of Sport (AIS) also have a sports supplement framework which is based around the best available evidence to determine the safety, efficacy and legality of different supplements.

Which Supplements Work And Which Are Banned?

Using the AIS framework it becomes clear which supplements have strong evidence to support their use and which don’t. Grade A supplements backed by strong evidence which aren’t banned include:

  • Caffeine
  • Beta-alanine
  • Bicarbonate
  • Beetroot juice (nitrates)
  • Creatine
  • Glycerol

Grade B supplements, those containing emerging evidence or deserve further research include:

  • Carnitine
  • Fish oil
  • Curcumin
  • Branched Chain Amino Acids (BCAA)
  • Tyrosine
  • Vitamin C and E

Grade D supplements, those that are on the banned WADA list include:

  • DMAA (stimulant)
  • DMBA (stimulant)
  • DHEA (prohormone/hormone booster)
  • Maca root powder (prohormone/hormone booster)
  • “Peptides”

Don’t be drawn in by the bold advertising nor the websites and forums. Have a thorough understanding of the risks and benefits of any supplements being considered. Consult an appropriately trained health professional to see if you actually need to be taking any supplements at all, it maybe a change in diet and training is all that is required. There are ergogenic supplements out there that have good evidence to support there ability to enhance performance in endurance, sprint and power sports. However, there are also a great deal of supplements out there that have no evidence to support there use and may well even include banned substances, so make sure you know what you are putting into your body.

What you eat and drink pre and post workout are vitally important for performance optimization and recovery. This article provides an overview of the types of fuels and amounts needed to help fuel your body for optimal performance and recovery.

Fueling your body for optimal performance.