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Having Your Best Race Day

July 18, 2018

By Nick Whitbread

Hydration and Electrolytes : A balancing act

Part of a great race day performance is managing your hydration as well as your electrolytes. Studies have show that being dehydrated as little as 2% can have a 10% reduction on performance. That’s significant. Here’s some information to keep in mind for your next race. 

The body likes balance. We have a correct amount of water depending on our weight that our body should contain at any given moment. We require water for many functions within the body. We lose water through respiration (breathing), sweating, urination. Even when we are standing still on a cool day we are loosing moisture. 

Try this, we used to do it as an experiment to show customers how a breathable waterproof fabric worked when I worked in the Outdoor Industry. Take a lunch bag and put your hand inside, place a rubber band loosely around the wrist to seal the bag, wait 1 minute. For some people it doesn’t even take that long for the bag to get clammy and moist. We are losing moisture through our skin even when we are doing nothing. Now wash the lunch bag and re-use it. Waste not, want not. 

So what happens when you get dehydrated? Nothing good. 

Fatigue: non vital organs get their water supply cut off, your running muscles, non vital

Urine gets dark: kidneys hold onto what water they have and urine becomes more concentrated, your body is attempting to balance the system 

  • Lightheadedness: your blood pressure drops and you start feeling dizzy

  • Heart rate increases: less water reduces electrolyte transportation as electrolytes go down heard rate goes up. 

  • Overheating: water in the body helps to maintain a regular temperature

  • Headache: the brain needs water to function and send messages (nausea, vomiting or diarrhea or constipation)

So it’s the night before the race and everyone’s telling you to “stay hydrated”. So you start guzzling water like never before in an effort to have a great race the following day. How do you know you weren’t hydrated properly already? 


Signs of good hydration:

  • Urine: your urine should be a light yellow. If it’s clear you are over hydrated and your body is dumping water

  • Skin: your skin should be nice and pliable. Try pinching the skin of your forearm up by your elbow. It should be easy to grab and have some stretch. If its tough or uncomfortable to grab its a sign that your skin is lacking moisture and you're dehydrated (or you have a fascial restriction in that area but that’s a talk for another day)

  • Lack of fatigue: you feel good, full of energy

  • Mental clarity: you’re thinking clearly

Keep these in mind and give yourself a check before you try and empty Niagara the night before the big race. 

So you check yourself (before your wreck yourself) the night before your race and manage your hydration. What about Electrolytes? Now is when it gets fun. The symptoms of being low on electrolytes are similar to that of dehyradion. 

Symptoms of low electrolyte levels

  • Irregular heartbeat

  • Increased heart rate

  • Fatigue

  • (Nausea, vomiting or diarrhea or constipation) 

Water and Electrolyte management go hand in hand. Too much or too little of either and the body becomes unbalanced and then performance suffers. The two most common thought of electrolytes are sodium and potassium. The others are chloride, magnesium and calcium. You need all 5 to remain functioning well. Keep this in mind when choosing your electrolyte source for your race. Always read the label before you buy.

So how do you know where you’re at with electrolytes? This is much tougher than just hydration. Most of us live day to day with enough electrolytes, it’s only once we introduce extreme heat situations or exercise that we need to be mindful of replacing them. 

So how much do I drink and how do I mange my electrolytes? 

Research has show that the human body can’t process more than 800ml of water an hour. So let that be your top marker for an extremely hot day where you are running hard and sweating a lot. Obviously on a cooler day or at an easier pace you sweat less (insert Antonio joke here) and your body isn’t working as hard so it uses less water. So adapt accordingly. 

You can also do a sweat test. Try to be hydrated properly, weigh yourself naked and then run at your race pace for 30 minutes without consuming liquid. Return home (it’s awkward for the neighbours when they catch you weighing yourself naked outside) and weigh yourself again. The amount of weight lost will let you know how much water you lost through sweat during that time. Multiply it by two and there’s your hourly sweat loss and a starting point for your hydration needs. Running for an hour would give you more accurate data, just be sure to hydrate and replace the electrolytes when you’re done if you’re exertion level was high.

Most electrolyte tabs will recommend you take one tab every 45 minutes and to vary this with exertion and heat. If you are using a powdered product like Tailwind they recommend a starting number of scoops per hour and adding from there depending on exertion. 

So we just told you what the company said, now what? Now comes the testing. Training is the testing ground for your racing. Experiment with how often and how much you are hydrating and consuming electrolytes. It’s different for everyone. 

In a long race it can be incredibly challenging to figure out if you need more water or electrolytes or both, when you start feeling off. I have run out of water in races before in a long section and become dehydrated. When I got water again I guzzled it but didn’t at the same time consume enough electrolytes and the problem became exponentially worse, as I became severely depleted of electrolytes. 

One tell tale sign of being low on electrolytes is your hands. The body is trying to maintain a balance of water and electrolytes within your cells as well as your extracellular spaces (the cavities outside you cells). Think of electrolytes as the glue that water sticks to so that it can be transported into your cells. When there’s not enough, your body buffers that by not allowing the water entering the body into the cells. Instead it pushes excess water into your extracellular spaces so the primary balance within the cells can be maintained. This is what happens in the hands. If the skin on your hands feels tight or your hands appear swollen with fluid during a race, its a good sign that you are low on electrolytes (if you are racing at altitude swollen hands is also a sign of altitude sickness). In this situation a tab form of electrolytes is preferable as your body already has more water than it know what to do with. 

Hydration and Electrolyte balance is something that is really best maintained by testing in training and feel during the race. Know what worked for you in training and pay attention to the markers for dehydration and your mental state. These will be the best measures. Don’t wait till you feel thirsty to drink. Drink like you did in training.

Antonio’s Husband AKA Garry Robbins has an interesting lesson he teaches his athletes during training with fueling. They must carry their minimum 200 calories per hour for their long run with him and if they are not consumed during the run they must all be consumed in the trailhead parking lot before the run can be considered completed. We don’t want you to wait that long with your fluids and Electrolytes. Better to be a little too full than a little too empty in this case. 

We hope this was helpful

Tailwind nutrition
Drop bags image
Ultramarathon race kit
race plan electrolytes
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