Dehydration & How It Affects Performance

Dehydration & How It Affects Performance

We’re always warned about dehydration, but it’s important to understand why it’s such a significant concern. As you may know, the body can go without food for quite some time, but without water — even for a few days — vital body functions and processes start to suffer.


You might think of dehydration as just being thirsty or tired, but there’s more to it.


The body is over 95% water, and maintaining proper fluid balance — both in and out of cells — is crucial to sustain bodily functions and blood volume. When body fluid levels drop significantly, we experience what is called dehydration — the amount of fluid taken in is less than the amount being lost, leading to an imbalance. So when you feel thirsty, it’s not just your mouth craving fluids, it’s also your cells.

The main source of fluid loss for athletes is sweat. And while knocking back a couple of litres of water after exercise sounds like a great idea, you’re essentially only preventing over-heating. This is because you don’t just lose fluid when you exercise — you lose electrolytes, too. They are crucial to many functions, especially with respect to the nervous and muscular systems. If you're exercising often, you definitely want to avoid impairment to your nervous system and muscles.

Electrolytes, technically speaking, are minerals that carry a charge. When dissolved in water (or any other liquid), they dissociate into positively charged and negatively charged ions and help to regulate nerve and muscle function, as well as maintain pH and water balance. Sodium is the most commonly known electrolyte, but calcium, potassium, magnesium, chloride, and bicarbonate are electrolytes, too. They’re all important in specific ratios in order to maintain fluid balance within the body.

The mechanism behind electrolyte loss is fairly simple. Sweat is comprised of mostly water, but also salt, protein, urea, and ammonia. When we sweat during exercise, we lose large amounts of water, sodium, and chloride. We also lose potassium, magnesium, and calcium, just in smaller amounts. Remember how we said all electrolytes are needed to maintain fluid balance? When we lose large amounts of specific electrolytes, we throw the ratios off and the body is unable to complete its functions properly.


It's important to be able to distinguish between being thirsty, and being dehydrated.


The truth is, it isn’t always easy to recognize severe dehydration — the symptoms aren’t always as obvious as thirst and fatigue. But we’ll tell you this: if you’re thirsty, you’re already dehydrated. Being dehydrated isn’t irreversible, but it’s important to catch it early, before it begins to compromise body functions. Here are some symptoms of mild dehydration to watch out for:

  • Dry mouth
  • Fatigue
  • Dry skin
  • Headache
  • Constipation
  • Dizziness or lightheadedness
  • Low urine output
  • Muscle cramps or muscle fatigue

If you’re reaching severe dehydration, be on the lookout for these symptoms:

  • Bad breath
  • Cravings, especially for sweets
  • Dark-coloured urine
  • Low blood pressure
  • Rapid heartbeat
  • Rapid breathing
  • Irritability and confusion
  • Fever
  • Lack of skin elasticity/recoil

While this is all great information to know, let’s get down to the bottom line: why you should care.

As an athlete, your main goal is to increase performance and reduce recovery time as much as possible. Sodium chloride, also known as salt, is the electrolyte we lose most when we sweat. Sodium is an essential mineral for nerve cell communication and the regulation of fluid volume both in and around the cell. It also plays a major role in preventing muscle cramps — more so than potassium. While not a major contribute to muscle cramps, potassium has quite an important role in maintaining heart health; it regulates and maintains the contractions that keep the heart beating. Magnesium, on the other hand, is crucial to the synthesis of protein, lipids, and carbohydrates, as well as controlling neuromuscular coordination. Finally, calcium plays a vital role in enzyme reactions and nerve impulse transmission. In muscles, calcium reacts with proteins to cause the muscle to contract and relax, therefore causing movement.

But muscle contractions require adequate amounts of sodium, potassium, and calcium. Without them, we may experience muscle weakness or muscle cramps — two things we don’t want when we’re in the middle of an exercise or activity. In much the same way, nerve impulses also require electrolytes for transmission, and when we don’t have enough, we experience neurological imbalances. Together, this means a decrease in physical performance. As previously mentioned, electrolytes are also needed to maintain proper pH of the body. If the environment (the body) is too acidic, inflammation levels are high and muscles are unable to recovery properly.


So how do you prevent dehydration?


Besides ensuring you’re hydrated before, during, and after exercise, including an electrolyte supplement into your daily routine will prevent the extreme loss of electrolytes and any nasty side effects that come with it.


1. Price, Anita. "What is dehydration?" Ostomy Quarterly, Spring 1989, p. 26. Academic OneFile, Accessed 18 Oct. 2018.
2. Dolan, S. (n.d.). Electrolytes: Understanding Replacement Options. Retrieved from https://www.acefitness.org/certifiednewsarticle/715/electrolytes-understanding-replacement-options/ 
3. Mercola, J. (n.d.). What Happens to Your Body When You're Dehydrated. Retrieved from https://articles.mercola.com/dehydration-symptoms.aspx 
4. Bailey, E. (2018). Electrolytes: Performance Perks and Real Food Sources. Retrieved from https://blog.nasm.org/fitness/electrolytes-performance-perks-and-real-food-sources/ 
5. Lytle, M. (n.d.). Electrolytes for Muscle Recovery. Retrieved from https://www.invitehealth.com/article-electrolytes-for-muscle-recovery.html