The modern sports industry has convinced many people that dehydration is a terrifying fate to be avoided at all costs.
We are advised to seek out the best hydration drink and take in so many litres per hour of sports recovery products that supposedly help us stay hydrated.
But do we need to worry about this?
How much hydration do you need?
When it comes to hydration, size — body size, that is — matters.
Your surface area and volume help determine your water needs. The bigger you are, the more fluids you lose through respiration and sweating.
Temperature matters as well. If like myself you are lucky enough to live in year around warm weather, you need to factor in that heat will suck fluid away from the body faster.
I drink a lot of water, well at least I try to if I don’t, I feel crap. That doesn’t necessarily mean everyone is affected in the same way. Much of the information we take as gospel for proper athletic hydration is based on the needs of male athletes who are exercising in extreme conditions.
In fact, the oft-cited guideline of “Drink X glasses of water a day” isn’t based on evidence.
It’s one of those things that gets repeated often enough to become “well-known”.
But the science doesn’t support it.
Your body is smart
Water and proper fluid balance are pretty essential for life.
So thirst is controlled in one of the oldest, deepest parts of our brain. And there’s a complex regulatory system that organises the delicate body balance of electrolytes (such as sodium and potassium) and fluids (i.e. water).
Our bodies are pretty smart.
They get thirsty when they need water.
We drink water. The body is happy.
We often try to out-think our intelligent bodies.
We drink — often to excess — when we aren’t thirsty because we’re afraid of being “dehydrated”.
What happens when you over-hydrate?
Drinking enormous amounts of water too quickly (and without replacing electrolyte/minerals properly) can lead to electrolyte imbalances in our body.
Hyponatremia (hypo- meaning: low, -natremia meaning: blood sodium), occurs when there are too much plain water and too little sodium in the body fluids outside our cells.
Mostly, our cells “drown”.
Too much plain water dilutes our extracellular sodium levels. Water then pours into our cells as our body tries to balance things.
Our cells then swell because of the water pouring in. Not good.
As the water content of the blood continues to increase, the body can’t get rid of the fluids fast enough. The excess water then goes to the bowels, which pulls salt from the body, further diluting our body sodium. The brain swells.
It’s a vicious cycle that leads to massive cellular damage affecting muscle, brain, heart liver, and kidney function.
But now that you’re totally freaked out, here’s the good news.
Over-hydration/hyponatremia is very real. But it only happens to endurance athletes who train for hours, sweat significantly (losing lots of sodium in their sweat), and drink gallons of plain water without ever replenishing their sodium levels.
Hmm, sounding scarily like me again!
Or, in other reported cases, over-hydration has occurred when people drink too much water (usually in the range of 7 litres of plain water or more in the span of two to three hours) at raves, or in one notable case, as part of a radio-show water-drinking contest.
No worries here, my raving days are well behind me.
How to get a healthy amount of water
Drink when you’re truly thirsty. Pace yourself.
Over-hydration isn’t necessarily about the amount of water you drink overall.
It’s about whether your fluid intake overwhelms your body’s ability to deal with it.
A healthy human kidney should be able to process and excrete up to 10 litres of water per day.
While you certainly shouldn’t try to reach that capacity, a couple of litres of water spread evenly throughout the day will be just fine.
You might have heard some myths about hydration, such as:
MYTH: Your urine should be clear.
MYTH: If you wait until you’re thirsty to drink, it’s too late, and you’ll probably shrivel up like a prune.
MYTH: Real “fitness people” guzzle water like they just stumbled out of the Sahara.
None of these is right.
Trust your body to give you thirst cues — We’ve had millions of years of evolution to form our hydration habits, we just need to tune in.
Have a glass of water with meals.
Not only will this help you absorb the sodium you consume, but it’ll also ensure that you don’t mistake thirst for hunger. (A great body cue to learn for weight management.)
If you found this post helpful, please leave a comment below or if you have any handy tips to keep you aware of how you fuel your body for fat loss and performance it would be great to hear them.