Electrolytes and Summer Training (and Racing)
By Coach Morgan Hoffman
Summer is here, and so is the double-trouble combo of Texas heat and humidity – athletes who have been enjoying a relatively cool spring will now need to adjust hydration plans to account for these two aspects of summer training in the south, or suffer the consequences.
Before we discuss how to adjust your hydration plan, let’s talk about the effects of heat on performance, and why we need to adjust.
Why is it so much harder to perform in the heat?
What exactly is happening when your body is forced to deal with increased heat, and why does 170w on the bike feel like 200w when the temperature shoots up? To answer this question, we must first understand that the human body is designed to operate efficiently at a temperature of around 97.5-99.5 degrees Fahrenheit. Anything above this, and an individual becomes subject to mild to severe physiological compromises/failures (I won’t go down this wormhole today, but there is plenty of literature available on the subject).
The body cools itself by creating sweat, which cools the body as it evaporates (if you’ve ever had that post-race chill on a cool day when your body is covered and sweat and suddenly the 60 degrees that felt GREAT during the race suddenly feels like an arctic blast – that’s what’s happening). To create sweat, more blood is sent to the skin, and water and electrolytes are released. Because the body is sending more blood to the surface, less blood is available to send to muscles (including the stomach, meaning in-race nutrition becomes harder to digest and absorb), and because water and electrolytes (plasma) are being released, blood volume is decreasing and blood is becoming thicker, again making it harder to get blood to the muscles. Since there is less blood volume to send to the body in these circumstances, the heart starts working harder (beating faster) to send blood more quickly. Thus the reason why you can produce 200w in 60 degrees at the same heart rate that only allows you to produce 170w at 90 degrees.
Today will not be focused on adapting your race/training strategy to address heat (though we can have that conversation in the future), but on adapting your hydration strategy to ensure that your body is able to properly cool itself, and maintaining blood volume even as more blood is being pumped to the skin versus the muscles.
Why does humidity seem to make workouts worse?
Remember that our bodies cool themselves via the evaporation of sweat – humid conditions prevent the evaporation of sweat due to the increase of liquid in the air. That means our body can struggle to cool itself at 70 degrees and 100% humidity in the same way as at it does at 90 degrees and 50% humidity. Humidity means the body will work harder to cool itself, and athletes and coaches must take this into consideration when devising a hydration plan.
What is an electrolyte?
Electrolytes are inorganic micronutrients responsible for everything from regulating bodily temperature to activating neural communication in the body. They are not actually a source of energy, but they facilitate a wide range of bodily functions necessary to life and athletic performance.
As we mentioned above, sweat doesn’t just release water from the body, it also releases electrolytes, particularly sodium. Sodium is a key electrolyte because it actually helps our body process and retain water, meaning more water is put to good use, versus just flushing through the system. In other words, hydration means a balanced intake of water and sodium, not just water. Excessive water consumed without accompanying sodium (particularly during prolonged exercise in warm/humid conditions) will not necessarily go towards necessary functions, and can even cause hyponatremia (the condition of having low blood sodium, which can cause swelling in the brain).
Other electrolytes include chloride (as in sodium chloride, or table salt), potassium (of particular interest to endurance athletes due to its role in facilitating neural communication) and magnesium. It is important for athletes to note that the primary electrolyte lost via sweat is sodium. Other electrolytes are generally consumed throughout the day via food sources, and do not need to be heavily replaced during exercises, though many sodium replacements now often include a mix of other electrolytes as well. However, as athletes, our focus should be replacing sodium, and at Playtri we build our plans around this electrolyte.
How do I know how much sodium to take?
We have a fairly simple test for determining hydration at Playtri. Like any good science experiment, it requires the collection and analysis of data – the good news is, very little scientific knowledge is required to make adjustments and achieve results.
For every long workout (more than 1 hour for runs, more than 2 hours for bikes) that our athletes do, they are required to fill out a nutrition report – this report includes:
· Date/time of workout
· Type of workout and length
· Temperature at time of workout
· Humidity at time of workout
· Pre-workout meal/hydration (anything 2 or less hours prior to starting the workout)
· Weight prior to workout (it is best to weight without clothing on)
· Calories consumed during workout and frequency of ingestion (include specifically the number of calories from carbohydrates)
· Ounces of water consumed during the workout and frequency of drinking
· Milligrams of sodium consumed during the workout and frequency of ingestion
· Weight immediately after finishing the workout (again, best to weight without clothing)
Look at the weight before and after the workout – if you didn’t lose any weight, then you aren’t dehydrated, and whatever you ate and drank was a good formula for your training/racing in those particular conditions. If you did lose weight, it means that either water or electrolytes (or both) need to be increased in the next workout (assuming conditions are similar). Always be aware that the hotter/more humid the conditions, the more water and sodium you will need to take.
If you aren’t sure where to start, I recommend trying 10-20 oz of water and 100mg of sodium per hour in a workout, then building from there. Heavier athletes will need more, lighter athletes will need less – remember if your body starts telling you something isn’t working, you need to listen. If you are dying of thirst utilizing the above recommendation in a workout, go ahead and drink more, and/or take more sodium. If you’re feeling distinctly sloshy, you can back off on hydration.
How often should I take in electrolytes?
We recommend taking electrolytes at least once an hour, if not more often. Small doses of macronutrients and micronutrients tend to be absorbed more efficiently. The same goes for water and calories, by the way.
Can’t I just mix my water, calories and sodium into a drink and use that?
While the one-stop-shopping nutrition/hydration approach is appealing for obvious reasons, we have found it to be less effective than separating our three primary intake items (water, sodium, and calories of carbohydrates) due to the variable nature of race day. When everything is mixed together, you have zero options to adjust one area on the fly based on the feedback your body is giving you. Need more water? Sorry, it has to come with more sodium and calories. Feeling sloshy? You have to keep drinking – have to get those carbs in before the run!
Begin gathering data and creating an effective hydration plan now – if you are a coached athlete, discuss with your coach the plan they have for you. Summer training and racing, as well as any late-season races, will benefit from your efforts. Remember that hydration is not just intake of water, but a balanced intake of water and electrolytes lost during sweat, and even though you may be able to maintain blood volume through proper hydration during a workout, your body still has to work harder due to the increased need for blood at the skin surface. Last, remember that performance is a bit like a science experiment – we must gather data, analyze, and adjust to achieve the best solution. Use the nutrition report to determine the hydration strategy that is best for you.