How Dehydration Is Killing Your Performance at the Office + Gym


Sometimes health advice gets preachy. Especially the “eight glasses of water a day” adage. Like, stop nagging already, right? But, it turns out there’s major truth to this one. This transparent, tasteless liquid holds the key to your mood, cognition, cardiovascular output, and even your lifespan. So, what purpose does all that H20 really serve? And why are eight glasses so necessary?

We dug into the fascinating biology of why water improves your heart, mind, and treadmill sprint. It’s time to get down with viscosity.

Dehydration makes you crabby & distracted

What are the signs and symptoms of dehydration? It’s not just thirst. These two studies found dehydrated participants felt anxious and unfocused. The experiments measured vigilance, concentration, reaction time, learning, memory, and reasoning in both a hydrated and dehydrated state.

The dehydrated participants experienced headaches, fatigue, difficulty concentrating, increased tension, and anxiety. Amazing, right? Imagine next time you’re feeling annoyed or frazzled – you could just need a glass of water.


What’s more, the studies show that dehydration is not just a gym concern. Mild dehydration will sneak up on you over the course of a work day. The University of Connecticut reports, “The tests showed that it didn’t matter if a person had just walked for 40 minutes on a treadmill or was sitting at rest – the adverse effects from mild dehydration were the same.”

The study’s lead author, Lawrence E. Armstrong, said, “Staying properly hydrated is just as important for those who work all day at a computer as it is for marathon runners, who can lose up to 8 percent of their body weight as water when they compete.”

Without adequate hydration, bodies can experience more muscle soreness, the need for longer recovery times and less desire to push oneself – in short, dehydration can make you feel less motivated to achieve at any activity. –

Dehydration makes you physically weaker

If you don’t properly hydrate, you’re restricting one of the most precious resources to the heart: blood flow. That’s gonna really eff up your workout. Dehydration impairs your heart’s performance in three ways:

  • Lowers your potential max

It reduces your “maximum cardiac output,” the highest pumping capacity your heart can achieve during exercise.

  • Reduces blood volume

Dehydration decreases plasma volume. This leads to an increase in blood thickness (viscosity), which lowers the blood pressure in your veins. When your blood pressure is reduced, your heart doesn’t have the “oomph” it needs to return blood into the ventricles. When you go hard on the cardio equipment, this reduced blood volume means your heart doesn’t have the strength to “fill up” between heartbeats (known as the diastole phase in the cardiac cycle).

That means you won’t have the endurance or strength you normally do when fully hydrated. Heavy.

statistical-heart-model-factor-75Super cool 4D model of the left and right heart ventricles. Improper hydration shortens the rest phase of the cardiac cycle.

  • Inhibits ability to cool down

As your body tries to conserve water, it decreases your sweat rate. This causes you to overheat, which in turn raises your core temperature. This increases the rate of muscle glycogen use, making your body less efficient – meaning you’ll hit the wall faster.

If you feel thirsty, it’s already too late

Don’t wait until you feel thirsty to reach for your Nalgene. That’s why experts push the mythic eight glasses a day. We get dehydrated fast! If you don’t drink regularly, you’ll start experiencing the cognitive and physical repercussions of dehydration at one percent water loss. If you’re feeling thirsty, you’re probably already at two percent water loss.

Thirsty for more?

Check out this killer infographic below for more effects of hydration on health:

dehydration is making you sick and fat

Written by
Emily Hill
Factor 75 journalist & blog strategist. Nutrition science geek.

Healing, Health and Wellness Center of Shelby is proud to offer the finest Alkaline Ionized Water in the world today. Kangen Water® is the delicious, healthy water. “Kangen” means “return to origin” in Japanese.

Come by and receive your 2 free gallons of Kangen Water! ($1 fee for the jugs only) Location: 323 S. Washington Street Shelby, NC 28150 Telephone #: 704-457-1001 Across from Don Gibson Theatre Time: Tuesday – Friday from 11am to 6pm Saturday from 11am to 2pm



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