What you don’t know about sweat (and the rehydration formula to beat its side effects)

Thursday 21 May 2015
  • Sweat on skin
    Mmm... back sweat

You’re probably thinking...

“Do I really care about sweat? Is there really something so important about sweat that’s missing from my life?” 

Well, there is. And it’ll certainly change one crucial element of your workouts. 

Once you get your head around what sweating is all about, replacing what you lose and what happens if you don’t, you’ll never think of sweat the same way again. 

What I’m trying to say is that sweat and hydration go hand in hand. And doing one without the other is a recipe for disaster – or more specifically... 

DEHYDRATION (*cue sound effects*) DA DA DAAAAAAAA!          

[JUMP DOWN TO THE INFOGRAPHIC TO GET THE LOW DOWN ON HOW TO REHYDRATE RIGHT]

But first…

What is the gross, smelly stuff?

If you lick the back of your hand after a run, you’ll taste salt. (Maybe don’t do this is public though – bit creepy.)

Sodium is one of sweat’s main ingredients, along with chloride and potassium. And of course, water.

Your sweat is produced by two types of sweat glands. The eccrine glands, which we have millions of all over our body, and the apocrine glands, found where we have lots of hair follicles. Yup, I’m talking about our pits and naughty bits. 

So while the eccrine glands produce the standard sweat recipe; it’s sweat from our apocrine glands that exudes a different kind of brew. The smelly kind… 

Yes, sweat from the apocrine glands does carry a few extra by-products. But interestingly, it’s only when sweat hits the skins surface that it lets off an odour, and you can thank the bacteria on your skin for that. 

Needless to say, it’s always best to have a little extra scrub in those stink-prone areas.

Why do we sweat? 

Our body takes temperature regulation VERY seriously. 

Sweating is our body’s attempt to keep cool when things heat up.

Uncontrolled increases in body temperature can lead to lots of serious side effects, dehydration being one. So embrace sweat, don’t fight it! It's essentially your body going into survival mode.

What happens is that the H2O in our sweat evaporates, taking with it the excess heat caused by exercise. The harder you work, the more your muscles are metabolising and producing heat, and the more your body sweats to try to stay cool. Pretty clever, huh?

How much we sweat is NOT an indication of how fit you are. Instead, it’s based on lots of factors like age, gender, weight, fitness level and environment.

Someone who weighs more will generally sweat more, simply because they need to exert more energy meaning they overheat quicker. Plus they have more body mass to keep cool.

However, a really fit person still sweats just as much. It just means that their body is doing an efficient job at trying to cool down.

As for the environment, ever wondered why we sweat more in hot and humid weather?

Hotter usually means sweatier as our bodies will be working overtime to keep us cool. But humidity, or moist air, is a killer for evaporation, meaning we can’t lose heat through sweat as effectively. The outcome: a hot, sweaty, sticky mess. Yuck.

But don’t stress if you’re a ‘sweater’. It’s nothing to be embarrassed about. In fact, sweating when you workout is a sign you’re pushing yourself and it’s your body’s way of helping you work harder, for longer. 

Now that’s cool!

So I just need to drink some water, right?

Not so fast.

We’ve established that overall, sweating is a good thing. But the downside is that it can also lead to dehydration, especially when working out in the sweltering Brisbane heat. 

So the real question is: “how much water do I need to drink?”

You’ll be surprised how much and how fast you lose water during exercise. 

It’s vital that what goes out, MUST go back in (and then some). Otherwise you’ll end up feeling dizzy, headache-y and severe dehydration can even make you physically sick. 

The sweaty side effects

According to Dr Lawrence E. Armstrong – the lead scientist in a 2012 University of Connecticut study – loss of water and dehydration can affect our mood and even our ability to do everyday tasks:

“Our thirst sensation doesn’t really appear until we are 1 [percent] or 2 percent dehydrated. By then dehydration is already setting in and starting to impact how our mind and body perform. […] Dehydration affects all people, and staying properly hydrated is just as important for those who work all day at a computer as it is for marathon runners”.

The study found that even mild dehydration can cause headaches, tiredness and difficulty concentrating.

In a bad mood? A glass (or two) of water may just be the perfect pick-me-up. 

Bad breath, dry skin and even naughty food cravings are just some of the more odd and unexpected side effects of dehydration.

So exactly how much needs to go back in? And how do you even figure that out?

Well, as stated in Dr Lawrence E. Armstrong’s review Assessing Hydration Status: The Elusive Gold Standard

“Body weight change provides the simplest and most accurate index of hydration status”.

Riiigghhttt. So what does that mean…?

Don’t sweat! We’ve put together a sweaty, but snazzy, infographic to help you top up the tank post sweat sesh:

The Rehydration Calculation infographic

So now you know how to rehydrate right, share this info and help others get their hydration strategy sorted.

And remember, keep guzzling that H2O guys.

If you’d like more specialised advice to boost you or your sports team’s performance, get in touch with our sport science experts at the UQ Sport Academy.

Get in contact with the Academy here.

Flickr Creative Commons Image via Kullez.

 

Amy Cox

ABOUT THE AUTHOR
AMY COX
Amy is UQ Sport’s resident blogger. She’s a peanut-butter loving Brit, who exercises to eat whatever she wants. You’ll find Amy either in the gym, playing badminton or doing the wrong moves in group fitness classes.