Story At A Glance:
Effects of Dehydration:
Water is the most ubiquitous substance in the human body, accounting for 60-75% of total body weight. We continually lose water in our breath, sweat, urine, and feces. Most of us are dehydrated and don’t even realize it. A study from 2016 found that 32% of collegiate athletes started exercise in a dehydrated state when allowed to drink freely.1 This reinforces the fact that thirst is a poor predictor of hydration status. We don’t usually even experience thirst until we are already around 1-2% dehydrated, and this only gets worse as we age.
Now that we have established how important hydration is and what a profound impact it can have on mental and physical performance, lets look at how much, when, and what to drink.
How Much Water?
A review of the literature found that pre-exercise hyper-hydration improves endurance capacity and peak power output while decreasing heart rate and thirst sensation.4 For events lasting less than 4 hours, hyponatremia (dangerously low sodium) from excess water consumption is rare. However, for endurance athletes it is important to know your individual water needs so you can avoid this dangerous condition. This can be easily done by weighing yourself, then performing your event for an hour (in race like conditions) and then re-weighing yourself. For every pound you lose, replace 16-20 oz. of water per hour. If you keep to this formula during your event and start the event properly hydrated, then you should avoid over-hydration and dehydration.
You may have been told to set a timer on your watch and drink a sip every 10 minutes. First you have to understand that most water is absorbed in our small intestine and not in our stomach. The volume of fluid consumed at one time matters for absorption rates.5 When we drink less than 7 oz. it sits in the stomach longer than 13.5 oz. and 20 oz. moves through the stomach the fastest. One caveat here- don’t go overboard. Researchers found that 30 oz. or more actually slowed gastric emptying. So the take home is if your stomach can handle it, then drink a larger volume (14-20 oz.) less frequently for increased absorption rates.
What to drink?
Multiple studies have shown the benefits of consuming sports drinks with carbohydrates for optimal sports performance.6789 Carbohydrate-fortified beverages improve exercise performance in an effect that is independent of and additive to its effects on preventing dehydration. However, like fluid volume, the amount of carbohydrate matters. Anything over 7% causes delayed gastric emptying and slows absorption. 3-4% of daily value for carbohydrates is the ideal concentration.
Electrolytes can be a source of confusion and debate. While it is true hyponatremia can happen, and endurance athletes need to pay extra attention to this. Our body has mechanisms in the skin to aid the reabsorption of sodium from our sweat. The concentration of sodium in our sweat is actually 3.5 times less concentrated than in our blood, while the concentration of potassium in our sweat is 2.5 times more concentrated than in our blood.10 Most people focus on sodium when it comes to electrolyte replacement. However, potassium should not be forgotten. The typical American diet contains far more sodium than is recommended, and falls significantly short on potassium. Potassium is critical for energy production during the metabolism of glycogen in the muscle. Low potassium levels can lead to decreased energy and endurance. For most athletes, consuming a beverage such as Laird Superfood Hydrate that contains 3% DV carbohydrate with 10% DV potassium is an ideal choice for optimal hydration.